Category: Class 7

AP State Syllabus AP Board 7th Class English Textbook Solutions Chapter 4C The Emperor’s New Clothes Textbook Questions and Answers.

AP State Syllabus 7th Class English Solutions Chapter 4C The Emperor’s New Clothes

7th Class English Chapter 4C The Emperor’s New Clothes Textbook Questions and Answers

I. Answer the following questions.

Question 1.
Was the king wise?
Answer:
No, the king was not wise.

Question 2.
What would have happened if the old minister had told the king the truth?
Answer:
If the old minister had told the king the truth, he would have called that the minister a fool. And he would not have punished the weavers.

Question 3.
Why did everyone pretend that they could see the cloth?
Answer:
Everyone pretended that they could see the cloth because the weavers had said that fools could not see their cloth and so they did not want to be considered fools.

Question 4.
There are people who cheat as the weavers did. Share with your classmates what you know about such cheats.
Answer:
What I know about them is that they appear to be correct and our helpers. They pass nice and. sweet words which make us spell-bound. Later they cheat us. We lose something. So we should think well about what some boys say. We should analyse their words and find out the fact. We may, then, do what they say.

If everything you touched became gold, would you be happy?

King Midas was a very greedy king. Even though he was very rich, he always craved for more and more. Every day he prayed God for more and more. One day, God appeared before him and granted him a wish. Midas asked, “Give me golden touch – everything I touch should become gold.” God smiled and granted him the golden touch saying, “Anything that you touch will turn into gold.” The King was delighted with his good fortune. Everything he touched turned into gold. He turned trees, grass, tables, chairs, flowers, and vases into gold. He thought that he must be the richest man in the world.

But in the evening, when he sat down for supper, King Midas was not so happy. His food turned into gold the moment he touched it and’ he had to go to bed without any food! However, King Midas was too greedy to be sad about it.

The next morning, the King’s daughter ran to hug her father. But alas! The minute she kissed him, she turned into a gold statue! King Midas, who loved his daughter very much, was very sad and he ran to the temple for help. He cried, “God, please help me, I don’t want to be rich anymore. I only want my beloved daughter back.” God changed everything back to normal. King Midas had learnt his lesson and was never greedy again.

The Emperor’s New Clothes Summary in English

Once there lived an Emperor. He was very fond of new clothes. He spent his money on getting new clothes for himself.

One day two men came to his court. They said they could make the most beautiful cloth in the world for the Emperor. The Emperor was very much pleased with their words. They also told the Emperor that their cloth was so special that only wise people could see it, but fools could not. The Emperor thought by wearing clothes made with that cloth, he could see who were wise and who were fools in his kingdom. So the Emperor gave them a lot of money and told them to begin their work at once.

The two men were given a special room for their work. In that room, they set up two looms. They acted to be working. But there was nothing on the looms. They asked the king to give them the finest silk and the purest gold thread. The king did so. But they put those in their bags and acted working at the empty looms until late at night.

One day the king sent his old minister to the weavers to know how they were getting on with his cloth. The minister entered their room. He felt surprised to see nothing on the looms and the men doing nothing. The weavers asked the minister how the cloth they made was. The minister thought that if he said the truth, he would be treated as a fool. So, though he could see nothing there, he said that the cloth was very splendid.

Next time, the king went into the room along with his officers. Both the king and the officers could see nothing there. But they all said that the cloth was very beautiful.

At last the weavers said that the cloth was ready. They cut it with a huge pair of scissors in the air. They stitched the clothes with needles without any thread in them.

They told the Emperor that the clothes were ready. The weavers said that they made the trousers and the coat for the king. The officers said that they were beautiful though they could see nothing there. Even the king could see nothing but he could not admit it.

The two young men asked the king to put on the new clothes that they had made. The Emperor took off all his clothes and pretended to be putting on the new clothes. He knew he wore nothing but did not complain because he would thought to be a fool if he said the truth.

The Emperor walked along in the procession. People in the street cried that the Emperor’s new clothes were beautiful. But a little child said that the king had got nothing on, at all. Then all the people there cried that the king had got nothing on. The king felt greatly ashamed and unhappy. He knew that the people were right. But the procession had to go on.

The Emperor’s New Clothes Glossary

be fond of: like very much

weavers (n): people who weave cloth with thread

pretended (v): acted

foolish (n): person having no knowledge / wisdom

empty (adj): nothing

take off (v): remove

AP State Syllabus AP Board 7th Class English Textbook Solutions Chapter 4B Dear Mum Textbook Questions and Answers.

AP State Syllabus 7th Class English Solutions Chapter 4B Dear Mum

7th Class English Chapter 4B Dear Mum Textbook Questions and Answers

I. Answer the following questions.

Question 1.
Who do you think is responsible for all the mischievous deeds?
Answer:
I think it is none but the’ naughty boy who is responsible for all the mischievous deeds.

Question 2.
Why was there a strange jam stain on the kitchen wall? How do you think did it happen?
Answer:
There was a strange jam stain on the kitchen wall because the boy must have taken out the jam in the kitchen in his mother’s absence and he might have touched the wall with the jam- stained fingers.

Question 3.
Did the boy play only indoors? Support your answer.
Answer:
Yes, I think the boy played only indoors. The things happened in the house during the absence of his mother clearly indicate that he had done all those while playing indoors.

Question 4.
What do the muddy foot prints on the carpet suggest?
Answer:
It suggests that the boy might have invited some of his friends into his house to play indoors and they all walked with muddy foot on the carpet.

II. Work in pairs and discuss.

Question 1.
Have you ever been mischievous? Share with your partner some mischievous deeds that you have done in the past.
Answer:
Yes. I have been mischievous quite often. I used to turn off the burning stove in the middle of cooking. Turning on lights during day time, allowing cat to drink milk, giving away new chappals of father to beggar, etc. are other activities of mischief. They are too many to list out.

Question 2.
If you were mischievous like the boy in the poem, how would your mother react?
Answer:
My mother would react with a smile and gentle warning most of the times. She would be very angry and beat me sometimes.

Project

I. Read one or two stories about Tenali Raman and share them in your groups.

A Story about Tenali Raman’s Wit

Tenali Ramalinga was a jester and courtier in the court of king Krishnadevaraya. He was known for his wit and humour.

Tenali Ramalinga’s wife had a lot of jewels. She wore them in the day. At night, she put them away, in a box. She kept the box in her bedroom.

Tenali Ramalinga had two servants. They were rogues.

One day the two servants decided to steal the jewels. One servant said to the other, “We will steal the jewels in the night.” Then the other servant said. ‘Yes, it’s a good idea because in the night, they will be asleep. Then we will easily take away the box of jewels.” At that time, Ramalinga was standing behind the two servants and overheard what they had said. It was dark and so they did not see Ramalinga.

At night, they stood behind the door of the bedroom. Ramalinga knew that they were behind the door. So he said loudly, to his wife, “My dear! We hear that these days thefts are increasing. So our bedroom is not the safe place to keep the box of your jewels, in. I shall drop this box of jewels into the well which is in our garden.” The servants thought that the box of jewels would be dropped into the well. But Ramalinga cleverly took out all the jewels from the box and filled the box with small stone-pieces. Later he came out with box, went to the well and dropped the box into the well. He then returned to his bedroom.

After sometime, the two servants went to the well. They began the work of drawing out the water from the well. They poured the water into the garden. They did this work all the night, yet they couldn’t draw out all the water from the well. At day break, one servant said, “Friend, we’ll stop the work now and do it again tonight.” When they were about to go out, Ramalinga called them to his side. They turned, saw him and were surprised and speechless. Ramalinga told them, “You dirty rogues ! You wanted to steal my wife’s jewels. That’s why 1 filled the box with stones and threw it into the well. Nevertheless, you did one good thing. You watered the garden completely by drawing out the water from the well, all the night. Because of your bad conduct, I dismiss you both. Get lost now itself.” The two servants lost their job and went away.

II. Make a fun cap.

Kings have gone. Jesters have gone. Now, we have only jokers in circuses or comedy shows. They wear fancy dresses and a round cap on their heads. Work in pair, one student should give the following instruction and other has to follow it and do accordingly.

1. Take a round colour drawing sheet and cut it along the dotted lines.
   
2. Hold both the corners of the sheet and overlap the cut parts to fit like a cap. Use two paper clips to hold the shape or apply gum along the edge to fix.
   
3. Decorate your cap by pasting shapes of different colours, (e.g. triangles, flowers, squares, circles, etc.)
   
4. Cut long strips of different colours.
5. Make a small cut on the top of your cap and push the ends of the long strips inside through the hole and paste them inside.
   

Dear Mum Summary in English

The poet says that some naughty children do naughty things both at home and at school. They cover their mistakes pr faults cleverly and nicely.

In this poem, a naughty boy made mischief when her mother was not at home. When she returned, before her mother’s asking him why he had done those things, the boy began to tell his mother the reasbns for various happenings in the house during her absence. He said that while she was out, a cup went and broke itself. A crack appeared in the blue vase. He did not turn on the tap but mysteriously the sink overflowed. He also expressed his surprise on how the cat managed to turn on the washing machine (especially from inside) or how the self-raising flour’ managed to self-raise. He said he was terribly afraid when a series of muddy footprints appeared on the new white carpet. He said he was not the cause of all these happenings and that he was good and honest. He said that he thought that the house was haunted, by ghosts, when he had gone over to his grandmother.

Dear Mum Glossary

mysteriously (adv): strangely

scared (v): frightened of something

haunted (adj): (of a building) believed to be visited by ghosts

have a fit (phr. v): to be shocked, upset or angry

self-raising flour (n): flour that contains a substance which makes cakes swell when they are cooked

gran (n): grandmother

for a bit: for a while

turn on (phr. v): switch on

AP State Syllabus AP Board 7th Class English Textbook Solutions Chapter 4A Tenali Paints a Horse Textbook Questions and Answers.

AP State Syllabus 7th Class English Solutions Chapter 4A Tenali Paints a Horse

7th Class English Chapter 4A Tenali Paints a Horse Textbook Questions and Answers

Look at the following picture and answer the questions that follow.

Question 1.
Look at the title and guess what you are going to read about?
Answer:
I am going to learn about the painting of a horse, painted by Tenali Raman.

Question 2.
Who do you think is the person with the turban?
Answer:
He is Krishnadevaraya, the King of Vijayanagara.

Question 3.
Can you name the person sitting on the throne?
Answer:
He is King Krishnadevaraya.

Question 4.
What do you think Tenali Raman will do its the story?
Answer:
As per the title, I think Tenali Raman will make painting of a horse, show it to the king and say something about it.

Question 5.
Can you share a story about Tenali Raman?
Answer:
Yes, I can’ tell a story.

I. Answer the following questions.

Question 1.
Why did Tenali Raman look displeased?
Answer:
Tenali Raman looked displeased because there was no completeness in the artist’s painting. The other side of the men in the painting and the face of the cow in the painting were not seen. He thought that it was not a good painting.

Question 2.
How did the king reward the artist? What would you have done if you had been in the king’s place?
Answer:
The king gave a bag of gold for his paintings saying that they were impressive. I would have given money or some valuable things to the artist.

Question 3.
Why did the king call Tenali Raman an ignorant fool?
Answer:
The king called Tenali Raman an ignorant fool because Raman said that only one side of the two men in the painting was seen. He also said that the face of the cow in the painting was not seen.

Question 4.
What do you think is the reason for the courtiers sniggering?
Answer:
The reason was that they strongly believed that Tenali Raman could not present a painting better than that of the artist and that Raman would lose the bet.

Question 5.
What was the bet between the king and Tenali Raman?
Answer:
The bet between the king and Tenali Raman was that if Raman could bring the king a painting that was at least half as good as the paintings of the artist, the king would give Raman a bag of gold and the title, ‘King of Artists’.

Question 6.
If you were Tenali Raman, would you accept the bet?
Answer:
If I were Raman, I would accept the bet because in my view, I would certainly win the bet.

Question 7.
How did Tenali Raman win the bet?
Answer:
Tenali Raman painted only the tail of a horse and showed it to the king. He said he had painted a beautiful horse. When the king said that he couldn’t see a horse in his painting, Raman said that the missing parts were to be imagined as the king had earlier said. Thus he won the bet.

Question 8.
Could you predict that Tenali Raman would win the bag of gold?
Answer:
Yes, I could predict it because Tenali Raman was very clever and witty.

Question 9.
If you were Tenali Raman, what would you do?
Answer:
If I were Tenali Raman, I would also have painted an incomplete picture so as to say that the missing parts were to be imagined.

Question 10.
Can you suggest a different ending to the play? Discuss it in your group.
Answer:
The different ending is bringing the painting that could display completeness in it and showing it to the king to please him and get the reward from him.

Vocabulary

I. Fill in the blanks with suitable words given below.

1. Birbal was a ——– in the court of Akbar.
2. The teacher was ——– with the nice work done by his pupils.
3. Sarada paid a ——– for not paying the fees on time.
4. When I visited Kashmir, the mountains were ——– with snow.
5. You should use your ——– when you look at a painting.
Answer:
1. jester
2. pleased
3. penalty
4. covered
5. imagination

II. Phrasal Verbs:

A phrasal verb is a phrase which consists of a verb and a preposition or an adverb or both, the meaning of which is different from the meaning of its separate parts.
You have really caught him out, Sir.
Perhaps his painting is so good that he can’t bear to part with it.
The words in bold are Phrasal verbs. The phrase ‘caught out’ means ‘showed that somebody does not know much. The phrase ‘part with’ means ‘to give something to somebody else, especially something that you would prefer to keep.

1. Consult a dictionary and list other phrasal verbs beginning with ‘catch’ and‘part’ Write some sentences of your own for each phrasal verb.
Answer:
Some phrasal verbs with ‘catch’:
1. catch on: become popular or fashionable.
Example: Guravaiah invented a new game but it never really caught on.
2. catch out: surprise somebody and put them in a difficult position.
Example: Many investors were caught out by the fall in share prices.
3. catch up: reach somebody who is ahead by going faster.
Example: Go on ahead. I will catch up with you.
4. catch upon: spend extra time doing something because you haven’t done it earlier.
Example: I have a lot of work to catch upon.
Phrasal verb with ‘part’: part with: give up, give away
He won’t part with his money, no matter what.

2. Read the following passages, circle the phrasal verbs, and guess their meanings. You may choose the meanings from the list given in the box. Write the phrasal verbs and their meanings in your notebook. Write one sentence of your own for each phrasal verb.

1. Ramana Rao’s house was robbed of. Venkateswara Rao, the inspector of police who was looking into the case released the picture of the suspect and asked the people to look out for him. In a press release, he said that he had some clues and that the robber could not get out of the case.
2. Bhanu joined a new company. In the beginning, she had problems with her manager. But now she is getting on with her new boss very well. Initially, she had problems with her paying-guest accommodation too. But the superb food her host served made up for the uncomfortable room. Now the problem is with looking after the host’s children. They are like little devils. God only knows how she would get through this.
Answer:
1. Ramana Rao’s house was robbed of. Venkateswara Rao, the inspector of police who was looking into the case released the picture of the suspect and asked the people to look out for him. In a press release, he said that he had some clues and that the robber could not get out of the case.
2. Bhanu joined a new company. In the beginning, she had problems with her manager. But now she is getting on with her new boss very well. Initially, she had problems with her paying-guest accommodation too. But the superb food her host served made up for the uncomfortable room. Now the problem is with looking after the host’s children. They are like little devils. God only knows how she would get through this.
a) looking into: investigating
b) look out for: notice someone
c) get out of: avoid or escape
d) getting on: managing
f) looking after: take care of
e) made up for: compensated for
g) get through: succeed

Sentences using the above phrasal verbs:
a) The police are looking into Nitya’s murder case.
b) Look out for Pandu while you’re there.
c) I reckon her backache was just a way of getting out of the housework.
d) Of late, Prakash is getting on quite well with his superiors.
e) This year’s good harvest will make up for last year’s bad one.
f) We look after the neighbour’s pigeons while they’re away.
g) We can’t get through to the government just how serious the problem is!

III. Idioms:
Read the following sentence from the play:
It’s only fair that if he doesn’t make good his boast…
The underlined phrase is an idiom. What is an idiom? An idiom is a phrase similar to the phrasal verbs you have just learnt. It is difficult to guess the meaning of an idiom by looking at the individual words. Here ‘make good’ means ‘to carry out a promise’.
Some other idioms that begin with make are: make merry, make do, make it, make the most of something, make something of yourself, and make like.
1) make merry: enjoy oneself by singing etc.
It is free time and all the students are making merry in the playground.
2) make do: manage
It is really my bad luck that I have always to make do.
3) make it: be successful
He has a strategy to make it in any area of activity.
4) make something of yourself: to be successful in life.
He made something of himself very quickly.
5) make like: act or behave in a specified way.
He was forced to make like the officer.

Look up these idioms in a dictionary and find out what they mean.
Here are some more idioms. Guess their meanings and use them in your own sentences:
1. once in a blue moon
2. bury the hatchet
3. to make both ends meet
4. to burn the midnight oil
Answer:
1. Once in a blue moon: Very rarely
Ex: My sister Padmaja lives in Australia, so I only see her once in a blue moon.
2. Bury the hatchet: forget the enmity.
Ex: They decided to bury the hatchet and try to be friends again.
3. To make both ends meet: earn money for one’s living
Ex: Jesse, to make both ends meet, had to run against horses.
4. To burn the midnight oil : work or study until late at night.
Ex: Just before examinations, she burns the midnight fail.

Grammar

I. Short forms

You have already learnt that an apostrophe shows that something belongs to someone or something before it. It has another use. When one or more letters are omitted in a phrase, an apostrophe is put where they have been left out; thus making it a short form of the original word. Short forms are used when we write a conversation, as it was done in the play you read. However, when these elements are used as main verbs, (Kamala is a lawyer) or used for emphasis (I will do it.), they are not contracted.

1. Pick out some short forms( contracted forms) used in the play and write their full forms in your notebook as shown above.
Answer:

2. Read the following conversation between Sarada and Usha and rewrite it in your notebook using the short forms.
Sarada: What are you going to do after school?
Usha: I will go home and take rest for an hour.
Sarada: Then, when will you cook supper for your children?
Usha: I need not cook today. I have made some Pulihora in the morning. We will eat it for supper too.
Sarada: Forgot to tell you this. I planned a quiz for 6th class children. Are you coming tomorrow?
Usha: I will not. I am taking leave for two days.
Sarada: Why? Are you going somewhere?
Usha: I would love to do that. But my mother-in-law is visiting us tomorrow.
Sarada: Then you will have a hard time, I suppose.
Usha: I do not think so.
Answer:
Sarada: What are you going to do after school?
Usha: I’ll go home and take rest for an hour.
Sarada: Then, when’ll you cook supper for your children?
Usha: I needn’t cook today. I’ve made some Pulihora in the morning. We’ll eat it for supper too.
Sarada: Forgot to tell you this. I planned a quiz for 6th class children. Are you coming tomorrow?
Usha: I’ll not. I’m taking leave for two days.
Sarada: Why? Are you going somewhere?
Usha: I’d love to do that. But my mother-in-law is visiting us tomorrow.
Sarada: Then you’ll have a hard time, I suppose.
Usha: I don’t think so.

II. Adverbs of manner
Revision:

We can make adverbs from adjectives by adding –ly as shown below:
Adjective + ly = adverb
safe + ly = safely
eager + ly = eagerly
However, you should remember that all adverbs are not formed in the same way.
For example you can’t add –ly to the following adjectives to make adverbs: good, fast.

Adverbs of manner tell us the manner in which something happens. They are usually placed after the main verb or after the object.
Look at the following sentences from the play you have read.
1. The courtiers are waiting eagerly for Tenali to bring in his painting.
2. Tenali looks at the giggling courtiers angrily and walks out.
In the first sentence the adverb ‘eagerly’ comes after the main verb Awaiting’.
In the second sentence the adverb ‘angrily’ comes after the object ‘courtiers’.

Difference between an adjective and an adverb:
An adjective qualifies or describes a noun or a pronoun.
Ex : She is beautiful. He is sad.
An adverb qualifies or describes a verb or an adjective or an adverb itself.
Ex : 1. He paints beautifully. (adv)
2. He paints very beautifully. (adv)
Generally, by adding ‘ly’ to adjectives, adverbs can be formed.

Adjective + ly = Adverb
Ex : 1. soft + ly = softly
2. safe + ly = safely
3. eager + ly = eagerly
4. sad + ly = sadly
5. slow + ly = slowly
6. slight + ly = slightly
7. sweet + ly = sweetly
8. nice + ly = nicely

However, it is to be noted that all adverbs are not formed merely by adding – ‘ly’.
Example: The adverb of good is well but not goodly.
The adverb of fast is fast but not fastly.
Adverbs come after the main verbs.
Ex: They are waiting eagerly for my brother.
Adverbs can come after the objects.
Ex: She looks at them angrily.
Adverbs of manner indicate the manner or the way some action is done. Ex: He goes silently.
It says how he goes.
Adverbs of manner can be identified by getting the answer for the word ‘how’.

Complete the following sentences with the correct form of the words in brackets.
Tick (✓) the sentences where the adverb of manner is put after the object and put a cross(✕) against the sentences where the adverb of manner is put immediately after the main verb.
Answer:
1. Sriram speaks ______ English. He speaks English ______. (correct)
2. Saleem is a ______ tailor. He makes dresses __________. (careless)
3. You always speak _________ . Please speak _______. (loud, quiet)
4. Be _______ and do your homework __________. (careful, correct)
5. Nandu is a _______ reader. He reads books very _________. (slow)
6. Please be _______ or do your work ________. I want to sleep. (quiet)
7. My mother shouted _________ when I showed my progress card.(loud)
8. Please listen ________ .(careful)
9. P.T.Usha is a ________ runner. She runs very _______. (fast)
10. Raghavathi is a _________ teacher. She teaches very ______. (good, well)
Answer:
1) correct: correctly (✓)
2) careless; carelessly (✓)
3) loudly ; quietly (✕)
4) careful; carefully (✓)
5) slow, slowly (✓)
6) quiet; quietly (✓)
7) loudly (✕)
8) carefully (✕)
9) fast; fast (✕)
10) good; well (✕)

Writing

Imagine that you were the King Krishnadevaraya. Now narrate an account of what had happened in your court. You can start like this:

One day, an artist came to my court and showed me some paintings. They were very beautiful. I liked them very much. Everyone in the court liked them except Tenali Raman ….
Answer:
One day, an artist came to my court and showed me some paintings. They were very beautiful. I liked them very much. Everyone in the court except Tenali Raman liked them. Tenali Raman said that the other side of the two men and the face of the cow were not seen in the picture. So they were not such good paintings. I thought that he was an ignorant fool. I told him everything could not be painted and he should imagine the missing bits of the painting. Then he bet that hb could paint better than that picture. I also bet him if he could paint a picture that was half as good as the picture drawn by the artist. I said I would give him a bag of gold and the title “King of Artists”. All the courtiers thought how scornful he was. They were certain he would lose the bet. But I knew he was clever and somehow he would get out of it. Eventually the day on which Tenali Raman was to show his paintings came. Everyone was eagerly waiting for him. It was lunch time. Raman not yet came. The courtiers took advantage of the situation and made ridiculous remarks against him. I was hungry and impatient. Then there came Raman followed by two men carrying a painting covered with a sheet of cloth. When Tenali gestured, the men lifted the cloth to display the painting. The painting had only a few curved strokes of black on the right hand edge and a few lines of green at the bottom below it. Raman said that he had drawn a black magnificent black stallion with a white star on its forehead. But I did not see anything on it. I was very much angry. I thought he was insulting me. There was nothing on this canvas. When I expressed my wrath he said that we should use our imagination when we looked at the paintings. He said that the horse was just outside the canvas grazing at grass. I thought he paid me in my own coin. The old rascal, he was clever, a hard nut to crack, defeated all the courtiers as usual. I gave him a bag of gold, as I had promised earlier.

Study Skills

Jesters used to entertain people with their wit and humour. Now we have comedians in films doing that job. Here is an interesting passage about one such comedian Mr. Rajababu.

Read on:
Sri Rajababu was a famous comedian in Tollywood. He was born in Rajahmundry, East Godavari District in Andhra Pradesh on 20 October 1937. He entered Tollywood in 1960 and acted until 1981. In his 21 year film career, he acted in more than 550 movies.
Can you imagine what he was doing before entering the Telugu Film Industry? Believe it or not, he was working as a Telugu teacher! Imagine how much fun his students might have had. Between 1955 and 60 he acted in many dramas. 1960 was a milestone in his life because that was the year in which he had his first chance to act in a film called ‘Samajam’. From that time onwards he never looked back. He married Lakshmi Ammalu in 1965. In 70’s he had become a very popular comedian and won many Filmfare Awards. His combination with Ramaprabha was a super hit and they were considered the best comedy pair.
In 1972 he acted as a hero for the first time in the movie Tata Manavadu.’ He acted as a hero in four more films. He produced films too. In 1974 he produced the film ‘Evariki Vare Yamuna Theere’. His film career came to an end in 1981 with the film ‘Gadasari Atta Sogasari Kodalu’. He could not act because of his ill health. This wonderful comedian, who was fondly called ‘Haasya Nata Chakravarthi’ passed away on 7 February, 1983.
Now, write the important events in the life of Mr. Rajababu on the timeline given below:

Answer:

Listening and Speaking

Your teacher will read the story ‘The Miser’ Listen carefully and answer the following questions :

The Miser
Once there was a very rich man. He was a miser. He ate cheap food and spent very little money. He lent money to small shopkeepers at a high rate of interest. In this way, he earned a lot of money.

Every morning he went out to see the shopkeepers and came home at midday. The miser had a watchman to look after his house. The watchman lived in a hut near the gate. He liked fish, and his wife cooked it for him every day. The watchman told his wife, “Cook the fish before midday. Our master will be out then. He doesn’t eat meat or fish, and he will not like the smell of fish.”

One day the master came home early. He walked past the watchman’s hut and caught the smell of fish. It was a nice smell and he liked it very much.

That afternoon, he called the watchman and asked him, “What were you cooking today?”
The watchman said quickly, “I won’t do it again, sir. Please forgive me.”
The miser said, “Don’t be afraid. I am not angry. What was your wife cooking? Please tell me.”
The watchman said, “We were cooking fish.”
The miser said, “Please cook it every day. I like the smell very much.”
The watchman and his wife thought, “Our master is mad.” But they cooked fish everyday.
After a month, one evening, the watchman and his wife came to see their master.

“Sir, you like the smell of fish,” the watchman said to his master, “so we cook it everyday. But fish is not cheap. It is very expensive. It costs us a lot of money. I earn only thirty rupees a month. You ordered us to cook fish even though we cannot afford it. So please give us money for the fish.”

The miser thought for a while. Then he said, “Oh, all right. Wait here.” He went into his room and shut the door behind him. He took out some silver coins from a bag. He dropped them one by one on the floor. The watchman and his wife heard the tinkle of the coins and were very happy. They said, “He is going to give us all that money!”
After sometime their master came out and sat down on a chair. He then asked the watchman and his wife, “Did you hear the tinkle of the coins?”

“Yes, sir, we did,” said the watchman.
“Did you enjoy it?” asked the miser.
“Yes, sir,” said’the watchman and his wife. –

The miser then said, “All right. I enjoyed the smell of your fish and you enjoyed the sound of my coins. I didn’t ask for your fish, so don’t ask me for my money. Now go away.”

1. Why did the rich man eat cheap food ?
2. Did the rich man like the smell of fish? Do you think he likes eating fish too?
3. If you had a lot of money, would you be a miser? Give reasons.
4. “please cook it everyday. I like the smell very much.” Who said this?
5. Do you think the watchman is honest? Support your answer.
Answer:
1. The rich man ate cheap food because he was a miser and so did not want to spend more money.
2. Yes, the rich man liked the smell of fish very much. Yes, he liked eating fish too.
3. If I had a lot of money, I would not be a miser. I would spend money on having a comfortable living and eating rich and healthy food.
4. The rich man (miser) said those words.
5. Yes, he was. Because he cooked fish for his master with his money instead of demanding for money.

I. Work in groups. Some groups can work on scene 1 and the others on scene 2.Rehearse and then present it before the class.
Answer:
Practise reading and enacting the ‘Tenali Raman Paints a Horse’.

II. Put yourself in the shoes of Tenali Raman and narrate what had happened in the court.
Answer:
One day when I was in the court of King Krishnadevaraya along with the other courtiers, an artist came to the king.

He showed his beautiful paintings to the king. We all looked at his paintings. The king was very much impressed with his paintings. He praised the artist saying that his painting was so beautiful and natural that he could almost feel the peace of the village scene. The king said that he was a very talented artist: The king gave him a bag of gold and asked the artist to stay in his court for some days for presenting him some more beautiful paintings. The artist was well-pleased and accepted his proposal. All the other courtiers also praised the artist for his beautiful paintings. But I was not happy as I did not like them. I told the king that the paintings were not very good as they had no completeness. Some parts of the painting were not seen. They were missing. The king, then, said that everything could not be painted. He also said that the missing parts must be imagined. Then I told the king: I could paint a better painting. Then the king bet that if I could bring him a better painting in a month’s time, he would give me a bag of gold and the title ‘King of Artists’. I accepted his bet. He gave me the paints and the paper.

After a month, I showed the king my, painting. I said that I had drawn the beautiful picture of a horse. The king got angry, saying that he could not see any horse in my painting. Then I said the tail of that the horse was seen and the rest of the horse was outside the canvas. It was to be imagined as everything could not be painted, as had earlier been stated by the king. Then the king understood my words and said that I had got the better, of him. He gave me a bag of gold praising that I was the cleverest man in his kingdom.

Tenali Paints a Horse Summary in English

Krishnadevaraya was the king of Vijayanagara. Tenali Raman was a poet and jester at his court: Tenali Raman was famous for his wit and intelligence. On many occasions, he made the king laugh at his jokes and witty answers.
The present drama ‘Tenali Paints a Horse’ is a proof of his wit.

One day, a great artist from another kingdom came to the court of the King. Krishnadevaraya. He showed the king his paintings. The king and all the courtiers except one were impressed with his paintings. It was only Tenali Raman who was not pleased with his paintings. The king said that the painting showed by the artist was indeed very beautiful and he could almost feel the peace of the village scene. He praised the artist and gave him a bag of gold. He asked the artist to stay in his court and paint some more beautiful paintings. Then Tenali Raman said that the paintings were not good. He said that the other side of the ‘ two men in the painting was not seen. Besides, the face of the cow, in the painting was missing. Then King Krishnadevaraya said that it was not possible for any painter to paint everything and that the missing bits in the paintings had to be imagined.

Then Tenali Raman told the king that he could paint better than the artist’s painting. King Krishnadevaraya told Tenali Raman that if he could paint a better painting, he would give him a bag of gold and the title ‘King of Artists’. He also told Raman to bring his painting in a month’s time. He said he would give Raman the paints and the paper. Tenali Raman replied he would return there after a month with his painting and show it to the king. Saying that, Raman left the court. All the other courtiers said that Raman could not paint a better painting nor would he complete and bring into the court in a month’s time.

A month’s time passed. The king was eagerly waiting with his courtiers for Tenali Raman’s return with his painting. As promised, Raman came into the court and showed the king his painting. Raman said that he had drawn the picture of a beautiful horse. Looking at the painting, the king got astonished and angrily said that he could see nothing on the canvas. Raman replied humbly that the edge of-the horse’s tail in the corner was clearly seen and that the rest of the horse was just outside the canvas grazing at some lush green grass. The rest of the horse was to be imagined because according to the king, the missing bits were to be imagined. The king understood his wit, felt happy and kept his promise to Raman.

Tenali Paints a Horse Glossary

1. wit (n): the ability to say clever and amusing things

2. jester (n): a man who tells jokes and funny stories

3. gestures (n): signals with hand

4. stallion (n): an adult male horse

5. imagination (n): guessing or expectation

6. paintings (n): pictures that have been painted

7. magnificent (adj): extremely attractive and impressive

8. whisper (v): speak very quietly to somebody so that other people cannot hear

9. display (v): show something to people

10. graze (v): eat grass that is growing in a field

11. canvas (n): a strong heavy rough material used by artist for painting

12. bet (v): risk money on race/event by trying to predict the result

SCERT AP 7th Class Science Study Material Pdf 10th Lesson Changes Around Us Textbook Questions and Answers.

AP State Syllabus 7th Class Science 10th Lesson Questions and Answers Changes Around Us

7th Class Science 10th Lesson Changes Around Us Textbook Questions and Answers

Improve Your Learning

I. Fill in the blanks.

1. Changes in which new substances are formed are called ______ changes.
2. Magnesium + Oxygen → ______
3. Milk converted to curd is ______ change.
4. Rusting of iron is protected by ______ process.
Answer:
1. Chemical
2. Magnesium Oxide
3. Chemical
4. Galvanisation

II. Choose the correct answer.

1. When a woolen yarn is knitted to get a sweater, the change can be described as
a) Physical change
b) Chemical change
c) Endothermic reaction
d) Exothermic reaction
Answer:
a) Physical change

2. The chemical chancre among the following is ______
a) Water to clouds
b) GroWth of a tree
c) Cow dung to bio gas
d) Ice to water
Answer:
b) GroWth of a tree

3. Which is an example of a periodic change?
a) Earth quake
b) Formation of rainbow
c) Occurrence of tides in sea
d) Showering of rain
Answer:
c) Occurrence of tides in sea

4. Photosynthesis by green plant is a
a) Physical change
b) Chemical change
c) Reversible change
d) None of the above
Answer:
b) Chemical change

III. Matching.

Group – A	Group – B
A) Growing hair	1. Chemical change
B) Breaking Mirror	2. Acetic Acid
C) Galvanisation	3. Slow change
D) Vinegar	4. Physical change
E) Atmospheric pollution	5. Depositing zinc on iron metal
	6. Fast change

Answer:

Group – A	Group – B
A) Growing hair	3. Slow change
B) Breaking Mirror	4. Physical change
C) Galvanisation	5. Depositing zinc on iron metal
D) Vinegar	2. Acetic Acid
E) Atmospheric pollution	1. Chemical change

IV. Answer the following questions.

Question 1.
Distinguish physical and chemical changes.
Answer:

Physical Changes	Chemical Changes
1) No new substances are formed.	1) During this new substances are formed.
2) The chemical properties of a sub-stance do not change.	2) The chemical properties of a substance changes.
3) It is temporary and reversible in nature.	3) It is permanent and irreversible change.
4) Change in the properties such as colour, shape and size of a sub-stance occurs.	4) A colour change may take place and sound may be produced. Heat or light may be ab¬sorbed or released.

Question 2.
When a candle is burnt, what type of changes takes place? Give another example of the similar process.
Answer:

1. When a candle is burnt both physical and chemical changes take place.
2. Burning of candle giving heat and light and reducing its size is a chemical change.
3. The wax melted during burning again condenses to solid wax is a physical change.
4. Part of the candle burnt is a permanent change and it cannot be reversed.
5. Due to the burning of the candle, carbon dioxide and water vapour are produced.

Examples:

1. Burning of LPG in our kitchen.
2. Liquid state of LPG in the cylinder is converted into gaseous state when comes out This is a physical change.
3. When LPG burns in air heat is produced, this is a chemical change.

Question 3.
Define crystallization.
Answer:
The process of separating a soluble solid from the solution by heating or evaporating is called crystallization.

Question 4.
Guess the consequences of burning crackers during festivals and celebrations.
Answer:

1. Firing crackers during festivals and celebrations increase the concentration of dust and pollutants in the air.
2. The dust particles get settled on the surrounding surfaces which are packed with chemicals like copper, zinc, sodium and magnesium. They cause damage to paintings.
3. The quality of ambient air will be decreased drastically.
4. Firing of crackers causes lot of sound pollution.
5. The oxides of sulphur pollute the air and causes lung diseases to human beings.
6. The increase in levels of air pollutants cause acid rains, corrosion of objects and decrease in visibility.

Question 5.
Prove experimentally chemical change is a permanent change.
Answer:

Aim : To prove chemical change is a permanent change.

Materials required :
Magnesium ribbon, water, match box, bunsen flame.

Procedure:
1) Take a small piece of Magnesium ribbon.

2) Burn it on a flame we will find brilliant white dazzling light leaving a powdery substance behind.

3) This is because when magnesium burns in the presence of oxygen, it forms magnesium oxide in the form of powdered ash. This is a new substance.
Magnesium + Oxygen → Magnesium Oxide (new substance)
This is a permanent change.

4) Now, take a small quantity of Magnesium oxide and mix it with a small quantity of water and dissolve it.
Magnesium Oxide + Water → Magnesium Hydroxide (new substance)
This is also a permanent change.
Here also another new substance is formed.

5) By testing this new substance with blue and red litmus papers. Red litmus turns blue. Then Magnesium Hydroxide is a base.

Inference :
Changes that occur with the formation of new substance with different chemical Coposition or transformation of a substance into another substance with the evolution or absorption of heat; or light energy are termed as chemical changes. These are permanent changes.

Question 6.
Guess the reasons for increase of plastic pollution.
Answer:
Main reasons for increase of plastic pollution :

1. Rising human population and their needs, people depend on plastic.
2. The food industry which packs everything on plastic.
3. Increase in usage of plastic bottles and container caps.
4. Indiscriminate usage of plastic bags and carriers.
5. Over usage of plastic straws and stirrers.
6. Lack of proper management of plastic waste.
7. Unawareness among the public about the hazardous affects of plastic wastes.
8. People are not following the 3’Rs (Recycle – Reduce – Reuse) method to reduce plastic wastes.

Question 7.
How can you appreciate the role of periodic changes in nature?
Answer:

1. Changes that are repeating at regular intervals of time are called as periodic changes.
2. Formation of day and night, for every 12 hours the sun rise and the sun set are repeating.
3. Seasons like summer, rainy, winter and spring occur every year at regular intervals.
4. The full moon and new moon repeats every month.
5. Heart beat of human beings takes place periodically.
6. Low and high tides in sea are periodic.
7. All these changes are periodically taking place in nature.
8. They provide us all comforts to live on this earth. I appreciate these periodic changes in nature for providing a happy life on this earth.
9. Without these changes in environment, life of us would become impossible.

Question 8.
Suggest some methods to prevent rusting of iron articles.
Answer:

1. The problem of rusting of iron and other metal articles is common experience in almost every home.
2. It spoils beautiful articles and makes them look ugly.
3. The following are some of the ways to prevent the rusting of iron.
   a) Do not allow the iron articles to come in direct contact with Oxygen in the air, water or both.
   b) Apply a coat of paint or grease on an iron article.

Question 9.
Ravi prepared carbon-dioxide using baking soda and vinegar. Carbon-dioxide changed lime water into milky white. Represent this experiment in a diagram with labelling.
Answer:

Preparation of carbon dioxide

7th Class Science 10th Lesson Changes Around Us InText Questions and Answers

7th Class Science Textbook Page No. 54

Question 1.
What change do you observe after removing mehandi applied on your palms?
Answer:
The hands get red colour after removing mehandi.

Question 2.
Can we clear the printed letters on paper. Why?
Answer:
No, it is a permanent change.

Question 3.
Water dispenser gives hot, normal and cold water. Is this natural or man made?
Answer:
Man-made.

7th Class Science Textbook Page No. 55

Question 4.
What is change?
Answer:
An act or process through which something becomes different.

Question 5.
How do we know that something has changed?
Answer:
By observing the changes in shape, size, colour and chemical properties.

Question 6.
What are the possible reasons for that change?
Answer:
They may be because of physical or chemical changes.

Question 7.
Is there any involvement of human beings?
Answer:
No, these are natural changes.

7th Class Science Textbook Page No. 56

Question 8.
Is there any change in its shape?
Answer:
Yes, it’s size will increase.

Question 9.
How does it happen?
Answer:
The air blown into the balloon occupies the space and the balloon becomes bigger in size. ,

Question 10.
Is it by itself or by anybody else?
Answer:
It is a man made change.

Question 11.
So what type of change it is?
Answer:
This is a man made change.

Question 12.
How much time they require?
Answer:
They require longer periods. It is a slow process.

7th Class Science Textbook Page No. 57

Question 13.
Have you ever noticed the following changes in our daily life?
Answer:
Yes. It is also a reversible change.

7th Class Science Textbook Page No. 58

Question 14.
Do the formed substance differs from original substance?
Answer:
Yes. The formed new substance is completely different.

Question 15.
Can we get original substance by reversing the conditions?
Answer:
No.

7th Class Science Textbook Page No. 50

Question 16.
Have you seen large crystals of sugar (Missrf) or crystal salt?
Answer:
Yes.

Question 17.
Do you know how we get these crystals?
Answer:
Yes. We get them through crystallization.

Question 18.
Have you ever observed the formation of small sugar crystals on sweets like Jilebi and badushah, which are kept aside for a long period?
Answer:
Yes.

Question 19.
What is the reason for this?
Answer:
It is because of crystallization.

Question 20.
What changes do you notice at the end?
Answer:
We notice the formation of large size crystals of sugar at the bottom of the beaker.

Question 21.
Do you find any crystals in the solution?
Answer:
No, we will find the crystals at the bottom of the beaker.

Question 22.
What type of change it is?
Answer:
It is a physical change.

7th Class Science Textbook Page No. 62

Question 23.
In Which cases new substances are formed?
Answer:
In chemical changes, we get new substance.

Question 24.
Have you observed rusting of iron, curdling of milk?
Answer:
Yes, I observed many times.

Question 25.
Do we get the same substance after change? Is the change is temporary or permanent?
Answer:
No, it is a permanent change.

Question 26.
Does the ash formed look like Magnesium ribbon?
Answer:
No.

Question 27.
Do you think the magnesium ribbon and the ash have the same composition?
Answer:
No

Question 28.
What do you observe?
Answer:
We get Magnesium Hydroxide.

Question 29.
Do you observe any change in the state of the substance?
Answer:
It is in liquid state (from solid state)

Question 30.
Is it an acid or base?
Answer:
Base.

7th Class Science Textbook Page No. 63

Question 31.
Did you observe iron nails, iron gates, iron benches or pieces of iron left in the open ground for a long time?
Answer:
Yes.

Question 32.
Did you observe any change in colour?
Answer:
We can observe a brown colour layer on the surface of iron articles.

Question 33.
How can we protect the iron articles from rusting?
Answer:
Through a process called Galvanization.

7th Class Science Textbook Page No. 64

Question 34.
Are there any other ways by which rusting of iron can be prevented?
Answer:
When the iron articles are coated with metals like chromium or zinc, we can prevent them from rusting.

Question 35.
Have you observed the handles of bicycles, metal rims of bicycle and motor cycles?
Answer:
Yes.

Question 36.
Do these articles rust? If not why?
Answer:
No, because they are coated with zinc or chromium.

Question 37.
What changes do you notice?
Answer:
We can notice a brown layer on their outer surface.

Question 38.
Can you prevent the browning of cut vegetables and fruits?
Answer:
Yes.

Question 39.
Have you observed your mother keeping the cut potatoes or brinjals in cold water?
Answer:
Yes.

7th Class Science Textbook Page No. 65

Question 40.
In which fruit or vegetable do you notice change in colour?
Answer:
In Apple, Brinjal and Potato.

Question 41.
Why does this change occurs?
Answer:
Because some vegetables and fruits react with oxygen in the air when they cut. Due to this oxidation process, brown layer is formed on the surface of these fruits and vegetables.

Think & Respond

Question 1.
When food gets spoiled, it produces a foul smell. Shall we call this change as a chemical change?
Answer:
When food gets spoiled by micro organisms, it produces a foul smell. By the action of the enzymes released by these microbes, the components of the food undergo chemical changes. Due to this, the food emits foul smell. It is a permanent change and irreversible in nature.

Question 2.
You know that plants produce their food by a process called photosynthesis. Can we call photosynthesis a chemical change?
Answer:
Photosynthesis is a chemical change. Here, carbondioxide is reduced to glucose. In this process oxygen is evolved. It is a permanent and irreversible change. New substance are formed.

Question 3.
Do all the materials react with oxygen in the air?
Answer:
No.

Question 4.
Observe Gold and Silver. You wear them in the form of ornaments. Even if they get exposed to air for long time, they do not change their colour. Why?
Answer:
Metals like gold and silver, even if they are exposed to air for a long time, they do not change colour or get rusted.

It means that they are resistant to corrosion which is the reason why we use them in making ornaments.

Activities and Projects

Question 1.
Collect information on the process of artificial ripening of fruits in fruit market and discuss whether it is useful or harmful.
Answer:

1. Calcium carbide more commonly known as “masala” is used for artificial ripening of fruits. It is very harmful to health.
2. Calcium carbide is a carcinogenic agent.
3. The most important precaution to avoid eating such artificially ripened fruits is to go in for fruits and vegetables which are not unseasonal.
4. Always wash the vegetables and fruits properly before consuming.

Question 2.
When you burn a piece of wood different changes take place analyse the following. Predict possible changes and list them all.
a) Are there any physical changes among them?
b) How many forms of energy are released in the change?
c) What chemical changes do you notice?
d) Explain briefly why these occur.
Answer:
a) No physical changes is observed.
b) The energy is released in the form of heat sound and light energy.
c) When a piece of wood is burnt a new material is formed (ash). We also notice change in shape and size of new materials (powder). This type of change which leads to form new substance is called chemical changes.
d) Wood turns into carbondioxide and ash
Carbon (Wood) + Oxygen (Air) → CO₂ + Ash

Activities

Activity – 1

Question 1.
What changes do you observe, When a balloon is blown?
Answer:
Change in the shape of balloon is done by blowing air into it. This is a man made change. When we left off the air from it, it returns to its normal shape. This is a physical change and reversible one.

Activity – 2

Question 2.
Observe the changes mentioned in the following table and complete it.

Change	Time taken shorter/longer duration	Type of change Fast/ Slow
1. Digestion of food
2. Burning a small candle
3. Occurrence of lightening
4. Construction of Dam
5. Rusting of iron

Answer:

Change	Time taken shorter/longer duration	Type of change Fast/ Slow
1. Digestion of food	Longer duration	Slow
2. Burning a small candle	Shorter	Fast
3. Occurrence of lightening	Shorter	Fast
4. Construction of Dam	Longer duration	Slow
5. Rusting of iron	Longer duration	Slow

Activity – 3

Question 3.
What changes do you notice when few pieces of ice in a beaker are heated? What do you mean by a physical change? Before heating After heating After freezing
Answer:

1. Take few pieces of ice in a beaker and heat them on burner as shown in the figure.
2. We notice that ice slowly melts and becomes water and on further heating it changes to steam.
3. If we reduce the temperature, the water vapour changes back to water and when temperature is further reduced it changes to ice.
4. In the above activity we notice the change of the state of ice to water and to vapour but the substance, water, remains the same.
5. Changes of this type where no new substance is formed are known as physical changes.
6. When a material undergoes a change in shape, size, colour or state it is called a Physical Change.
7. Generally, no new substance is formed in a physical change.

Activity – 4

Question 4.
Describe how do you perform the activity to observe the reaction of vinegar with baking soda?
Answer:

1. First set up the apparatus as shown in Fig.
2. Take a teaspoon of vinegar (acetic acid) in a test tube and add a pinch of baking soda (Sodium bicarbonate) to it.
3. You observe bubbles coming out with a hissing sound. Pass this gas through freshly prepared Limewater (Calcium Hydroxide).
4. Limewater changes to milky white showing that the gas sent into the test tube is Carbon dioxide.
5. Vinegar + Baking Soda → Sodium acetate + Carbon dioxide + Water
6. Carbon dioxide + Lime Water → Calcium Carbonate + Water
7. In these reactions the new substances like Carbon dioxide and Calcium Carbonate are formed. Hence it is a chemical change.
8. When a material undergoes a change in its composition it is called a chemical change.

Activity – 5

Question 5.
Write the approximate time after which they repeat.

Natural	Period of time of repetetion (Approximate)
1. Change of day and night	Every 12 hours
2. Withering of leaves
3. Rising of the pole star
4. Change of Seasons
5. Appearance of full moon

Answer:

Natural	Period of time of repetetion (Approximate)
1. Change of day and night	Every 12 hours
2. Withering of leaves	1 year
3. Rising of the pole star	24 hours
4. Change of Seasons	1 year
5. Appearance of full moon	30 days

Activity – 6

Question 6.
How do you produce large size of sugar crystals ? What type of change is it?
Answer:

1. Take a big size test tube. Fill half of it with water. Add some sugar to it and stir it.
2. Keep adding sugar and stirring until saturation is attained.
3. Then heat this sugar solution and add some more sugar to it while stirring continuously.
4. Continue adding sugar till no more sugar can be dissolved in it.
5. Now filter the solution and allow it cool for half an hour.
6. We notice formation of large size crystals of sugar at the bottom of the beaker. Thus the small granules of sugar added changed into large size sugar crystals.
7. This is a physical change.

Activity – 7

Question 7.
Some changes are given in the table. Write possible changes you notice for each case and put (✓) in the appropriate column.
Answer:

1) In the above activity we notice that only in some examples like burning of paper, burning of crackers, change of milk to curd, boiling of egg, etc., a new substance is formed.

2) But in other examples of changes we notice an change in state or colour or size or shape etc but the substance remains same and no new substance is formed.

Activity – 9

Question 9.
Complete the following table.

Name of the Fruit	Whether turned brown or not
	Yes	No
1. Apple
2. Brinjal
3. Potato
4. Tomato
5. Cucumber
6. Mango

Answer:

Name of the Fruit	Whether turned brown or not
	Yes	No
1. Apple	✓
2. Brinjal	✓
3. Potato	✓
4. Tomato		✓
5. Cucumber		✓
6. Mango		✓

Some fruits and vegetables when cut, react with oxygen in the air. The process of reaction with oxygen is called oxidation. Due to this process brown layer is formed on the surface of fruits and vegetables.

SCERT AP 7th Class Science Study Material Pdf 3rd Lesson Nutrition in Organisms Textbook Questions and Answers.

AP State Syllabus 7th Class Science 3rd Lesson Questions and Answers Nutrition in Organisms

7th Class Science 3rd Lesson Nutrition in Organisms Textbook Questions and Answers

Improve Your Learning

I. Fill in the blanks.

1. During the photosynthesis ________ gas is released.
2. The tiny pores present on the surface of the leaves are __________
3. ____________ is the outermost layer of teeth.
Answer:
1. oxygen
2. stomata
3. Enamel

II. Choose the correct answer.

1. Muscular tubular structure that connects pharynx with Stomach
a) Duodenum
b) Buccal cavity
c) Oesophagus
d) Rectum
Answer:
c) Oesophagus

2. Non insectivorous plant,
a) Drosera
b) Nepenthes
c) Utricularia
d) Dodder
Answer:
d) Dodder

3. The green colour pigment in the leaf
a) chloroplast
b) stomata
c) chlorophyll
d) all the above
Answer:
c) chlorophyll

III. Matching

A) Autotrophs	1. Mushroom
B) Saprophytes	2. Mango plant
C) Parasite	3. Food vacuole
D) Holozoic	4. Intestinal worms
E) Amoeba	5. Man
	6. Egestion

Answer:

A) Autotrophs	2. Mango plant
B) Saprophytes	1. Mushroom
C) Parasite	4. Intestinal worms
D) Holozoic	5. Man
E) Amoeba	3. Food vacuole

IV. Answer the following questions.

Question 1.
Distinguish between autotrophic and heterotrophic nutrition.
Answer:

Autotrophic nutrition	Heterotrophic nutrition
1. The mode of nutrition in which organisms make food by them selves is called autotrophic nutrition	1. The mode of nutrition in which organisms depend on other organisms for food is called Heterotrophic nutrition
2. Organisms that perform autotro phic nutrition are called autotrophs.	2. Organisms that perform heterotrophic nutrition are called heterotrophs.
3. They need carbon dioxide, water and sunlight to prepare their own food.	3. They don’t need these materials as they feed on other organisms for food.
4. They are green in colour due to the presence of a colouring pigment called chlorophyll.	4. They don’t have chlorophyll.
5. Ex: Plants	5. Ex: Animals

Question 2.
What is Photosynthesis? Write its word equation.
Answer:
The process by which green plants make their own food from carbon dioxide and water by using light energy in the presence of chlorophyll is called Photosynthesis.

Question 3.
Describe different types of teeth and their functions.
Answer:
There are four different types of teeth in our human beings.

1. Incisors :
The four front teeth in both the upper and lower jaws are called incisors. Thus there are eight incisors in the oral cavity. They have sharp incisal edge. Their primary function is to cut food.

2. Canines :
They are behind and adjacent to the lateral incisors on both the jaws. There are four canines in the oral cavity. They have single sharpcusp. Their main function is to tear food.

3. Premolars :
These teeth are located behind and adjacent to the canines. There are two premolars on the upper jaw and also two premolars on the lower jaw on either side of the mouth. Thus there are eight premolars in the oral cavity.These teeth can have 3-4 cusps. They are designed to crush food.

4. Molars :
The most posterior teeth in the mouth are the molars. There are 12 molars in the permanent dentition.They have broader and flatter surfaces with 4-5 cusps. They are designed to grind food.

Question 4.
What happens if leaves of a green plant are coated with green paint?
Answer:

1. If the leaves of a green plant are coated with green paint, then stomata present on the surface of the leaf will get blocked.
2. As a result exchange of gases will be affected.
3. So, plant may not get sufficient amount of carbon dioxide for photosynthesis and oxygen for respiration.
4. oreover, paint over the leaf prevents the reaching of sunlight to the leaf.
5. As a result plant will not be able to perform photosynthesis and respiration, gradually it leads to its death.

Question 5.
What questions will you ask a doctor to know about gastritis?
Answer:

1. What is gastritis?
2. What are the reasons for gastritis?
3. How can it be prevented?
4. Is there any relation between gastritis and life style?
5. Are there any home remedies to get relief from gastritis?
6. What is the treatment for gastritis?

Question 6.
How can you prove that the leaves other than green also carry out photo synthesis? (Activity – 2)
Answer:
Aim: To know whether leaves other than green perform photosynthesis or not.

What you need:
Red or brown coloured leaves, dropper; test tube, iodine solution, water.

What to do:
Take few Red or brown coloured leaves, add few drops of water and mash them to make a paste, collect the extract by squeezing the paste (pulp). Take 5-6 drops of this extract into a test tube. Also add two drops of iodine solution. Note your observations.

What do you see:
The colour of the leaf extract turns blue black.

What do you learn:
This shows the presence of starch in the leaves, confirming that red or brown coloured leaves also perform photosynthesis.

These non-green leaves also have chlorophyll. The large amount of red, brown and other pigments mask the green colour. So photosynthesis takes place in these leaves also.

Question 7.
Draw a neat labelled diagram of human digestive system.
Answer:

Question 8.
Draw a flow chart showing nutrition in amoeba.
Answer:

Question 9.
How will you appreciate the role of saprophytes in cleaning of the earth surface?
Answer:

1. Saprophytes grow on dead and decaying matter.
2. They secrete digestive juices on it, convert it into a solution and then absorb the nutrients from it.
3. During this process they decompose them and mix them with the soil.
4. In this Way they help in cleaning the earth surface by removing the dead and decaying matter.
5. This process help in recycling the nutrients too.
6. Thus they are doing a great service to the entire living world.

Question 10.
What precautions will you take to keep your digestive system healthy?
Answer:
To keep my digestive system healthy, I will

1. take simple and balanced diet
2. drink sufficient quantity of water.
3. brush my teeth regularly.
4. prefer natural foods.
5. avoid Junk foods and cool drinks.
6. never smoke.
7. never consume alcohol.
8. never chew tobacco and tobacco products.
9. do moderate exercises regularly.
10. take fibre rich food.

7th Class Science 3rd Lesson Nutrition in Organisms InText Questions and Answers

7th Class Science Textbook Page No. 37

Question 1.
My mother prepares food for me. Who prepares food for animals?
Answer:

1. Animals cannot make food.
2. They depend on other plants and animals for food.

Question 2.
How do animals get their food?
Answer:
Animals get their food from plants and animals.

Question 3.
Plant is a living thing. What is the food for it?
Answer:
Plants also need food, such as glucose, carbohydrates, minerals etc.

Question 4.
How do they get their food?
Answer:

1. Plants prepare their food by using photosynthesis.
2. Some plants get their food from other plants and animals.

Question 5.
What is the food for mushrooms?
Answer:
Mushrooms get their food from dead and decaying matter.

Question 6.
Even you might have got the same doubts?
Answer:
Yes.

Question 7.
Is the nutrition in plants same as in animals?
Answer:
No.

Question 8.
We eat food daily. But plants are not eating food then how are they living?
Answer:
Plants are able to live as they make their food themselves.

7th Class Science Textbook Page No. 38

Question 9.
How can the green plants prepare their own food?
Answer:
Green plants make their own food from carbon dioxide and water by using light energy in the presence of chlorophyll. This process is called photosynthesis.

7th Class Science Textbook Page No. 39

Question 10.
In which part of the plant, does photosynthesis takes place?
Answer:
The synthesis of food occurs in all green parts of plant body. For Ex : leaves.

Question 11.
How do the raw materials required for photosynthesis reach there?
Answer:

1. Plants get carbon dioxide from air through stomata in leaves.
2. Water obsorbed by the roots are transported to the leaves through the stem.
3. Chlorophyll captures the energy of the sunlight.

Question 12.
Do they perform photosynthesis?
Answer:
Yes, the plants with red and brown coloured leaves make their food in the process of photosynthesis.

7th Class Science Textbook Page No. 40

Question 13.
What is the importance of sunlight in photosynthesis?
Answer:

1. Sunlight is the source of energy in the process of photosynthesis.
2. The solar energy is captured by the leaves and stored in the plant in the form of food.
3. If there is no sunlight starch cannot be prepared in plants.

Question 14.
Plants get water from the soil through their roots. How does this water reach the leaves from the roots? What path does it follow?
Answer:

1. Water absorbed by the roots are transported to the leaves through the stem.
2. It follows the path from roots to leaves via stem.

7th Class Science Textbook Page No. 41

Question 15.
How do carbondioxide enters the leaves?
Answer:
Carbondioxide from air is entered the leaves through stomata which are present in the surface of the leaf.

Question 16.
How do oxygen comes out of the leaves?
Answer:
Through the stomata, oxygen produced in photosynthesis goes out of the leaves.

Question 17.
Where do these substances (starch, fats and proteins) come from?
Answer:
Plants produce sugar first, which is converted to starch and then other compounds like fats and proteins.

7th Class Science Textbook Page No. 42

Question 18.
There are some plants which do not have chlorophyll. How do they get their food?
Answer:

1. Organisms which do not have chlorophyll, cannot synthesis their food. They are heterotrophs.
2. Heterotrophic nutrition is of different types basing on how they obtain their food from other organisms.
3. Some plants depends on dead and decaying matter and some on other plants.

Question 19.
How do they (mushrooms) get their food?
Answer:

1. Mushrooms grow on dead and decaying matter.
2. They secrete digestive juices on it convert it into a solution and then absorb the nutrients from it.
3. This type of nutrition is called saprophytic nutrition.

Question 20.
A rat died at Pullaiah’s house. What happens to the body after few days? Do you find any traces of its body after a month? Where did that body go?
Answer:

1. Saprotrophs like fungi and bacteria will grow on the dead body of the rat, after a few days.
2. We cannot find any traces (except strong bones) of the dead body of rat, after a month.
3. The decomposed body of the rat is mixed with the soil.

Question 21.
How does Cuscuta survive? From where does it get nutrition?
Answer:

1. Cuscuta take readymade food from the plant on which it is climbing.
2. It develops special roots called haustoria, which penetrate into the tissues of the host plant and absorb food materials from them.

7th Class Science Textbook Page No. 43

Question 22.
How do animals take their food?
Answer:

1. Animals obtain their food from other organisms.
   Ex : Cow eats grass, cat drinks milk, dog eats meat.
2. They take the food in the form of solid or liquid.

Question 23.
Where do they digest it?
Answer:

1. Animals take food into the body for digestion.
2. Digestion occurs inside the body.

7th Class Science Textbook Page No. 44

Question 24.
What do you understand from Sabiha observations?
Answer:
Holozoic nutrition is the mode of heterotrophic nutrition in which the food is taken in solid or liquid form from the outside and is digested inside the body.

Question 25.
How do Amoeba takes its food?
Answer:

1. Amoeba has many small bubbles – like vacuoles in its cytoplasm.
2. Amoeba pushes out one or more finger – like projections called pseudopodia for movement and capture of food.
3. Food vacuole forms around the captured food.
4. Food get digested in it, absorbed into the cytoplasm and assimilates.
5. Finally, undigested food is sent out by opening this vacuole out at the body surface.

Question 26.
Is the nutrition in human beings also holozoic?
Answer:
Yes. The nutrition in human beings also holozoic.

7th Class Science Textbook Page No. 45

Question 27.
Have you ever wondered what happens to the food inside the body?
Answer:
Seeing the food that went into the body being digested, I was very surprised.

Question 28.
Do you have any structures like vacuole in our body?
Answer:
No.

Question 29.
Where do the food eaten by us go?
Answer:

1. We take food in the form of solids or liquids.
2. It goes to the digestive system, which is consisting of the alimentary canal and digestive glands.
3. Food get’s digested in the digestive system.
4. Digested food is absorbed by the blood.
5. Blood transports digestive food to different parts of the body for assimilation.
6. Undigested food will be ejected out of the body.

Question 30.
What change does the food undergo inside the mouth?
Answer:

1. We chew the food with the teeth and break it down mechanically into small pieces.
2. Carbohydrates are digested in the mouth.
3. Food also mixed with saliva and thrown into the stomach.

7th Class Science Textbook Page No. 46

Question 31.
How many kinds of teeth could you find?
Answer:
Four types of teeth.

Question 32.
Which teeth do you use for biting and cutting and which one for tearing?
Answer:

1. Teeth which are located at front side of the mouth are used for biting and cutting. (These are called incisors.)
2. Canines are used for tearing, which are located behind incisors.

Question 33.
Have you noticed formation of new teeth in the mouth of small children? Do all the teeth, wfiich sprouted first, remain forever?
Answer:

1. Yes. f have noticed that the formation of new teeth in the mouth of small children.
2. The teeth which sprouted first do not remain forever.

Question 34.
Do you know how does tooth decay happens?
Answer:
When food remains stuck in teeth, bacteria feed on them. As a result, lactic acid is produced, which causes the destruction of enamel and it leaves toothache.

7th Class Science Textbook Page No. 47

Question 35.
How does acid come into contact with teeth?
Answer:
When food remains stuck in teeth, bacteria feed on them. Bacteria produce lactic acid. This acid come to contact with teeth.

Question 36.
Do you now realise the importance of cleaning your teeth after food?
Answer:
Yes. It is very important. If we do not clean odr teeth properly after food, some food material will stuck in between teeth and causes tooth decay.

Think & Respond

7th Class Science Textbook Page No. 39

Question 1.
Testing tiie starch in the leaf directly with iodine had certain problems. To obtain results successfully think and discuss regarding this with your teacher.
Answer:

1. Leaves are green in colour.
2. When iodine solution is put on a leaf, it should turn blue if starch is present.
3. However, the green colour of the leaf disguises the blue colour.
4. More over cuticle present on the leaf hardly allows the iodine to reach he starch present in side the leaf.

7th Class Science Textbook Page No. 47

Question 2.
Which habit should be practised for the health of teeth? Why?
Answer:

1. Brush teeth twice a day with fluoride tooth paste.
2. Use dental floss to clean between your teeth.
3. Change your tooth brush every 3 months.
4. Cut down on how often you have sugary foods like chocolates, sweets and cool drinks. Visit dentist regularly.

The above habits should practise for healthy teeth. Because, if we do not clean our teeth and mouth after eating, many harmful bacteria begin to live and grow in mouth. These bacteria breakdown the sugars present from left over food and release acids. These acids gradually damage teeth and causes severe toothache.

Activities and Projects

Question 1.
Designer leaves making select any broad-leaved potte d plant. Cut a card board with a design of your choice and seal the selected leaf with the card board. Let the plant stand under the sun for a week then remove the card board. You will get designer leaves plant. Try to make more leaves with designs and display your plant but don’t forget to present your writeup.
Answer:

I have selected a potted plant with broad leaves.

I cut a design of my name first letter on a card board.

I sealed the selected leaf with the card board.

I kept this plant under the sun for a week.

Then I remove card board.

I surprised to see the design of my name first letter on the leaf.

Question 2.
Collect small plants, or the branches or other parts of big plants from your locality and classify them into autotrophs, parasites, saprophytes and symbionts. With the help of your teacher, preserve them in the form of specimens in the biology laboratory of your school.
Answer:
I have collected the following plants and classified them in to following categories.

Autotrophs:
Neem, mango, hibiscus, Paddy

Parasites:
Cuscuta, loranthus.

Saprophytes:
Mush rooms, Moulds Symbionts: Red gram, beans,

I preserved these specimens in the biology laboratory of our school.

Activities

Activity – 1

Question 1.
Fill the following table basing on your own observations and information collected from elders.

Answer:

Name of the organism	Prepare own food/ Depend on other organisms for food	Inference (Autotroph/ Heterotroph)
1. Mango tree	Prepares own food	Autotroph
2. Cat	Depends on other organisms	Heterotroph
3. Rose plant	Prepares own food	Autotroph
4. Mushroom	Depends on other organisms	Heterotroph
5. Leech	Depends on other organisms	Heterotroph
6. Goat	Depends on other organisms	Heterotroph
7. Human beings	Depends on other organisms	Heterotroph

→ Are all plants Autotrophs?
Answer:
No.

→ What kind of nutrition is seen in mushrooms?
Answer:
Heterotrophic nutrition (Saphrophytic).

→ What kind of nutrition is seen in animals?
Answer:
Heterotrophic (Parasitic, Holozoic).

7th Class Science Textbook Page No : 38 (Autotrophic Nutrition – Photosynthesis)

Question 2.
Anu said plants also prepare their food same as we prepare boiled rice.
Comparative table prepared by her was given below. Study the table and answer the questions.

	Preparation of Boiled Rice	Preparation of food by green plants
Raw materials	Rice, Water	Carbon dioxide, water
Source of energy	Fire from stove	Sunlight
Happens in	Vessel/cooker	Chloroplast in green parts
Finally forms	Boiled rice	Glucose/Carbohydrates

→ What are the raw materials required for the preparation of food by green plants?
Answer:
Carbondioxide, water.

→ Which gas is taken by plants during this process?
Answer:
Carbondioxide.

→ Name the food material formed in plants?
Answer:
Glucose / Carbohydrates.

→ What do you conclude from the above information?
Answer:
Plants prepare their own food.

Activity – 3

Question 3.
How do you prove that the sunlight is essential for photosynthesis?
Answer:
Aim: To know the importance of light in photosynthesis.

What you need :
Two potted plants, dropper, test tube, iodine solution, water.

What to do:
Take two potted plants of the same kind. Keep one in the dark (or in a black box) for 72 hours and the other in the sunlight. Perform iodine test with the Leaf extracts of both the plants as you did in activity-2. Note your observations.

What do you see :
The colour of the leaf extract of first plant does not change. The colour of the leaf extract of second plant turns blue black.

What do you learn :
This shows the presence of starch in the leaves of plant kept in the sunlight indicating the occurrence of photosynthesis. There is no starch in the leaves of the plant kept in the dark. This confirms that sunlight is essential for photosynthesis.

Activity – 4

Question 4.
How do you conduct an activity to show the saprotrophic nutrition in bread moulds?
Answer:
Aim:
To observe the saprotrophic nutrition ih bread mould.

What you need:
Piece of bread, water, a container and a hand lens.

What to do:
Take a piece of Bread, in a container. Sprinkle some water and close the container. Open the container after few days and observe. (Use mask and gloves while doing this activity).

What do you see:
You will see cotton-like threads spread on the piece of bread and bread size is decreased.

What do you learn:
These thread-like structures are some sort of plants called Fungi. They don’t have chlorophyll so they obtain their food from dead and decaying matter.

Activity – 5

Question 5.
Wash your hands. Look into the mirror and count your teeth. Use your index finger to feel the teeth. How many kinds of teeth could you find? Take a piece of an apple, sugar cane or bread and eat it. Which teeth do you use for biting and cutting and which one for tearing?

Also find out the ones that are used for chewing and grinding? Compare your observations with the given picture and fill the table.

(Note: The picture of teeth on lower jaw was given here. The number and type of teeth on the upper jaw is same as on the lower jaw.)

→ What do you find?
Answer:
I found different types of teeth in my mouth.

→ How many teeth do you have? Is it equal to the number given in the picture?
Answer:
I have 28 teeth. No, in the figure there are 32 teeth. But 1 have only 28 teeth.

→ Which teeth are absent?
Answer:
I have no (wisdom teeth). 4 molars are absent in my mouth.

Activity – 6

Question 6.
How does acid damage our teeth? Prove with an activity.
Answer:
Aim : To know the process of tooth decay.

What you need :
Marbles, dilute hydrochloric acid and test tube.

What to do:
Put a few small pieces of marble in dilute hydrochloric acid. Examine after awhile.

What do you see :
Acid reacts with marble and dissolves it.

What do you learn :
The enamel, which is a calcium compound, reacts with acid and gets destroyed in the same way a marble reacts with hydrochloric acid.

When food remains stuck in teeth, bacteria feed on them. As a result, lactic acid is produced, which causes the destruction of enamel.

SCERT AP 7th Class Science Study Material Pdf 7th Lesson Reproduction in Plants Textbook Questions and Answers.

AP State Syllabus 7th Class Science 7th Lesson Questions and Answers Reproduction in Plants

7th Class Science 7th Lesson Reproduction in Plants Textbook Questions and Answers

Improve Your Learning

I. Fill in the blanks.

1. Hibiscus propagated by _______ .
2. The male reproductive part in a flower is _______ .
3. The lower swollen part in gynoecium is _______ .
Answer:
1. stem
2. Stamens dr Androecium
3. Ovary

II. Choose the correct answer.

1. The plant which reproduces through leaves is
a) Bryophyllum
b) Rose
c) Hydrilla
d) Balsam
Answer:
a) Bryophyllum

2. The reproductive part in a plant is
a) Root
b) Stem
c) Leaf
d) Flower
Answer:
d) Flower

3. The agents of pollination are
a) Air
b) Water
c) Insects
d) All the above
Answer:
d) All the above

III. Matching

A) Potato	1. Stem cuttings
B) Bryophyllum	2. Seeds
C) Sugarcane	3. Leaves
D) Neem tree	4. Eyes
E) Banana	5. Anther
	6. Suckers

Answer:

A) Potato	4. Eyes
B) Bryophyllum	3. Leaves
C) Sugarcane	1. Stem cuttings
D) Neem tree	2. Seeds
E) Banana	6. Suckers

IV. Answer the following questions.

Question 1.
Identify whether the sentences below are true or not. Correct the statements which are not true
a) The flowers in pumpkin are unisexual.
b) Seeds are formed in asexual reproduction.
c) Generally, roses are propagated through seeds.
Answer:
a) The flowers in pumpkin are unisexual. This statement is true.

b) Seeds are formed in asexual reproduction. This statement is false. Seeds are formed in sexual reproduction.

c) Generally, roses are propagated through seeds. This statement also false. Generally, rose plants are propagated through a vegetative propagation method called stem cuttings.

Question 2.
What do you call the transfer of pollen grains to the stigma? Explain its types with the help of labelled diagrams.
Answer:

1. The process of transferring pollen grains from the anther to stigma is known as POLLINATION.
2. If the pollen grains are transferred from the anther of a flower to stigma of the same flower, is known as SELF POLLINATION.
3. If the transfer of pollen grains takes place from the anther of one flower to the stigma of another flower, it is called CROSS POLLINATION.

Question 3.
Can plants produce new plants without the seeds? Explain those methods with the help of examples.
Answer:

1. Yes, Some plants can produce new plants without seeds. This method of reproduction without formation of seeds is called asexual reproduction.
2. In some plants asexual reproduction occurs through some vegetative parts like stem, roots and leaf. Such a propagation is called vegetative propagation.
3. When the banana plants grow, a small new plant rises from the base of mother plant. Such small plants are called suckers (pilakulu). If we separate them and plant, they grow as new plants.
4. If we cut the sugarcane stem into pieces with at least one node and plant it in the soil. After few days new plants will develop from the nodes.
5. In Jasmine and chrysanthemum plants, small new plants arise from the underground stem of the mature parent plant. They are called layers. If these are separated from the parental plant and plant them in soil they grow into a new plants.
6. If we cut the mint twigs with nodes and sow them in soil, they develops roots and give the crop.
7. Potatoes have notches on them called eyes. If they are cut and plant in the suitable soil they gives rise to new potato plants.
8. In addition to these natural vegetative propagation methods, some artificial vegetative propagation methods such as stem cuttings, layering and grafting are also helpful to grow new plants with out seeds.

Question 4.
What happens if the pollen of mango flower reaches the stigma of guava flower?
Answer:

1. If the pollen of mango flower reaches the stigma of guava flower, fertilization does not occur.
2. Fertilization occurs freely between the individuals of the same specious (type).
3. But mango and guava plants belong to two different specious.
4. So, there will be no fertilization and formation of new plants.

Question 5.
If all the honeybees in nature become extinct. Imagine, what will be the consequences.
Answer:

1. Honeybees visit the flowers in search of nectar.
2. When insects come in contact with a flower, the pollen grains stick to their legs and wings.
3. Then insects visit another flower, the pollen fall on its slimy stigma.
4. Thus they play key role in pollination, intern helps in fertilization and formation of seeds.
5. If all the honey bees in nature become extinct, the fertilization in plants will reduce tremendously.
6. This results in the extinction of several specious of plants.
7. Agricultural productivity also will reduce to a great extent.
8. So we should stop indiscriminate use of chemical pesticides and protect honey bees.

Question 6.
What are the materials required, procedure and precautions taken by you in the lab activity conducted to study the parts of Datura flower?
Answer:
AIM: To observe the parts of a flower.

Material required:
Two datura flowers, new blade, magnifying glass, pencil. Procedure: Hold a datura flower by its stalk and observe its external features. Now draw the diagram of that flower in the box given below. Note down your observations. Now cut the second datura flower vertically into two equal parts from bottom to top. Check that all parts are cut into two equal halves. Observe and draw the internal view.

Precautions:
We should be careful while cutting the flower as the new blade is sharp and may cause injury. We should not inhale the pollen as it may cause allergy.

Question 7.
Draw the diagram of a complete flower and label the parts.
Answer:

Question 8.
Rahul goes to a field trip with his classmates, he tries to catch an insect on a flower. Do you support this?
Answer:

1. No, I never support Rahul.
2. Insects on the flowers helps in pollination and there by fertilization.
3. Catching and killing such insects effects the fertilization.
4. This leads to decrease the productivity of plants.
5. This hampers the propagation of that plants also.
6. All the organisms on this planet have the equal right live.
7. Killing of other organisms just for fun is a cruel act Which leads to imbalance in the nature.
8. “Live and let live” should be out motive.

Question 9.
Venkat, lives in a city. He maintains a roof garden at the top of his six storied building. The ridge gourd creeper bears plenty of flowers. But the flower do not grow into ridge gourds. Can you give him any suggestions to get ridge gourds?
Answer:

1. Flowers should pollinate and fertilize to form fruits.
2. Flowers on the ridge guard plant are unisexual flowers.
3. So, self-pollination is not possible.
4. For Cross pollination pollinating agents such as insects are required.
5. To allow the insects, if there is any net surrounding the plants, those should be removed.
6. Should not spray harmful chemicals on plants.
7. Along with ridge guard, other attractive flowers having nectar should be grown in the roof garden.
8. As a last trial do artificial pollination. (Transfer the pollen from male flower to the stigma of the female flower.)

Question 10.
Draw the various methods of Artificial propagations on a chart and exhibit in your classroom.
Answer:

7th Class Science 7th Lesson Reproduction in Plants InText Questions and Answers

7th Class Science Textbook Page No. 2

Question 1.
Can we grow all plants by planting their stems?
Answer:
No, we cannot grow all the plants by planting their stems.

Question 2.
How do new plants grow from the stems?
Answer:
New plants grow from the stems with some vegetative propagation methods.

7th Class Science Textbook Page No. 3

Question 3.
Have you ever seen seeds in Banana?
Answer:
In general we never found seeds in most of the hybrid banana varities. In certain varities of banana we can find small seeds. But in the wild varities we can find large sized seeds.

Question 4.
Have you ever seen seeds in Jasmine?
Answer:
Yes, I have seen seeds in Jasmine plants. Jasmine plants give long fruits from their flowers. These fruits contain seeds.

Question 5.
Did you observe how the Hibiscus plant propagate?
Answer:
Hibiscus plant propagate by means of stem cuttings.

7th Class Science Textbook Page No. 6

Question 6.
What would your mother have done to grow a basil / tulasi plant in your house?
Answer:
My mother sow the seeds of basil / tulasi in soil to grow the basil plant.

Question 7.
She might have put some seeds in the soil. Isn’t it?
Answer:
Yes. She would sow some seeds in the soil to get new plants.

7th Class Science Textbook Page No. 7

Question 8.
Which part of the plant form the fruit?
Answer:
Flower form the fruit.

7th Class Science Textbook Page No. 9

Question 9.
Do bitter gourd flower have whorls?
Answer:
No, bitter gourd flower has only three whorls. Either androecium or gynoecium are absent in them.

7th Class Science Textbook Page No. 11

Question 10.
Do you know which part of the flower will develop into a fruit?
Answer:

1. Ovary develop into fruits.
2. Ovules develop into seeds.

7th Class Science Textbook Page No. 12

Question 11.
Think, what changes will take place in the flower after fertilization?
Answer:

1. After fertilization, the ovary ripens and turns into fruit. ’
2. The remaining floral parts will fall off.
3. The ovules become the seeds.

7th Class Science Textbook Page No. 13

Question 12.
In which cup we observe healthy plants?
Answer:
The second cup contains healthy plants.

Question 13.
If all the seeds of a plant fall at the same place, how do the baby plants grow?
Answer:

1. Baby plants will suffer from deficiency of nutrients, water and place.
2. Their growth will be stunted.

Question 14.
Will they get sufficient place, nutrients, water to grow? What will happen if plants grow in such conditions?
Answer:

1. Plants will not have enough space to grow freely.
2. They will not get adequate amounts of nutrients and water.
3. They do not obtain healthy growth.

Question 15.
Do you have any idea that how plant overcome this situation?
Answer:

1. To overcome this problem, plants adopt different methods to disperse their seeds.
2. Seed dispersal takes place with the help of various agents.

Think & Respond

7th Class Science Textbook Page No. 12

Question 1.
Why do some plants produce small and numerous seeds?
Answer:

1. All the seeds of a fruit should be able to germinate to produce new plants. Actually, it does not happen in nature.
2. All the seeds don’t germinate, some will germinate but die before their maturity. Some of the seeds never germinate.
3. To over come all these problems, plants produce a large number of seeds.

Question 2.
Why do some seeds have wings?
Answer:

1. This type of winged seeds are dispersed by wind.
2. These wings help the seeds to move easily by winds to settle in a suitable place to germinate.

Question 3.
Why are some seeds with more fibre?
Answer:

1. Fibres make seeds light weight and help in floating.
2. These seeds dispersed through water for longer distance.
   Ex : Coconut.

Question 4.
Why do some pods of dry fruits explode?
Answer:

1. Some pods of dry fruits explode is a mechanical reaction.
2. In such way that they scatter the seeds all around.
3. In this way they dispersal the seeds.

Question 5.
Why do some seeds have hairs?
Answer:

1. Hairs help the seeds to travel in air.
2. Long haired seeds are travel long distances in air.
3. In that way seeds are settle at a suitable place to germinate.
   Ex : Calotropis.

Question 6.
Why are many fruits sweet and fleshy?
Answer:

1. Animals, birds and human beings eat these fruits and the seeds are thrown away.
2. Like that way, seeds will be dispersed to different places.
3. For the purpose of reproduction many fruits are sweet and fleshy,

Question 7.
Why do some seeds-have hooks?
Answer:

1. Seeds have hooks and thorns, help them to stick to the animals
2. So they travel one place to another place. Ex : Xanthium, urena, grass.

Question 8.
Why are some seeds heavy and round?
Answer:

1. Seeds that are heavy and round are dispersal by water.
2. They fall into the bottom of water
3. They carried by the flow of water for long distances.
   Ex : Seeds of Lotus.

Question 9.
Why are some seeds are delicate and small?
Answer:

1. This type of seeds are dispersed through winds
2. They are delicate, small, light in weight and hairy.
3. These qualities enable them to travel with the mind and settle at a suitable place to germinate

Activities and Projects

Question 1.
Collect information from elders, internet or your school library regarding the method of vegetative propagation in Onion, Garlic, Ginger, Gladioli, Sweet potato, Bryophyllum, Begonia.

Answer:

Plant	Method of vegetative propagation
1. Onion	New plants grow from bulbs.
2. Garlic	Individual garlic cloves are planted and they each produce a bulb.
3. Ginger	New plants are propagated through rhizomes.
4. Gladioli	New plants are propagated through corms (modified stems).
5. Sweet potato	New plants grow from modified roots.
6. Bryophyllum	New plants grow from the buds on the leaves (Epiphyllons buds)
7. Begonia	New plants grow from buds on the leaves (Epiphyllons buds)

Question 2.
Grow a plant using seeds and exhibit in the classroom record its growth.
Answer:

Activities

Activity – 1

Question 1.
Discuss with your friends and teachers and fill the table given below with ‘Yes’ or ‘No’ options. Answer the questions given below.

Name of the plant	Reproduce through seeds	Reproduce without seeds
1. Jasmine (malli)	Yes	Yes
2. Tamarind (chinta)	Yes	No
3. Curry leaf (Karivepaaku)	Yes	Yes
4. Banana (Arati)	Yes	Yes
5. Coriander (kottimeera)	Yes	No
6. Drumsticks (munaga)	Yes	No

i) Which plants are reproduce through seeds?
ii) Which plants are reproduce without seeds?
iii) Which plants are reproduce by both means?
Answer:
i) Tamarind, Coriander, Drumsticks plants repr oduce through seeds.
ii) Jasmine, Curry leaf, Banana plants reproduce without seeds.
iii) Jasmine, Curry leaf and some Banana plants reproduce by both means.

Activity – 2

Sheet For Lab Activity
Student Name : _____________________________________________
Date : _____________________________________________
AIM: To observe the parts of a flower.
Material required:
Two datura flowers, new blade, magnifying glass, pencil.

Procedure :
Hold a datura flower by its stalk and observe its external features. Now draw the diagram of that flower in the box given below. Note down your observations.
Parts of the flower :

External parts :
SEPALS:
Colour : Green Petal
Shape : Round tubular
Number : 5
Are they United/Separate ? United PETALS:
Colour : White
Shape v : Round tubular
Number : 5
Are they United/Separate? United

Procedure:
Cut the second datura flower vertically into two equal parts from bottom to top. Check that all parts are cut into two equal halves. Observe and draw the internal view.

Internal parts:
ANDROECIUM:
Colour : White
Shape : Thin filamentous
Number : 5
Are they United/Separate?
Separate
GYNOECIUM: Style
Colour : Light Yellow
Shape : Long tube like
. swollen at the base Ovary
Number : 1-Ovary – style – stigma
Are they United/Separate ? Separate Gynoecium

Activity – 3

Question 3.
Collect different varieties of flowers from your school garden. Take each flower and count the parts in it. Record the details in the given table.

i) Which flowers have all four whorls?
ii) Mention the flowers in which one or two whorls are missing.
iii) Write the whorl \ whorls which are missing.
Answer:
i) Lady’s fingers, Hibiscus and Datura flowers have all the four whorls.
ii) In Pumpkin, Bauhinia, Ipomea flowers one or two whorls are missing.
iii) Either androecium or gynoecium are missing.

Give examples for complete flowers …………………, ………………………, ………………….
Hibiscus, Datura etc.

Give examples for incomplete flowers …………………., …………………
Pumpkin, Ridge gourd, etc.

Activity – 4

Question 4.
Collect flowers of hibiscus, papaya, ridge gourd and some other flowers. Fill the table given below by observing the androecium and gynoecium.

i) In which plants either androecium or gynoecium is present?
ii) In which plants both androecium and gynoecium are present in the same flower?
iii) In which plant both androecium and gynoecium are present separately in different flowers of the same plant?
iv) In which plant both androecium and gynoecium are present in different flowers of different plants?
Answer:
i) Papaya, Ridge gourd, Bitter gourd
ii) Hibiscus, Datura.
iii) Ridge gourd, Bitter gourd
iv) Papaya

Activity – 5

Question 5.
How do you prove that seed dispersal is necessary for plants?
Answer:

1. Take two cups with soil.
2. Take handful of mustard seeds in the first cup and only four mustard seeds in the second cup.
3. Pour equal amount of water daily and observe them regularly for 15 days.

Observations:

1. Numerous plants germinated in the first cup. They have not enough space to grow freely. They are also not getting sufficient nutrients and water to grow. The plants present in the first cup are not healthy.
2. In the second cup, the four mustard seeds germinated into new plants. They have enough space, water and nutrients to grow. They are healthy.

Inference:
All the plants try to spread their seeds to distant places to increase the chances of survival and propagation. So, they adopt different methods to disperse their seeds. It occurs with the help of different agents.

PROJECT : Page No. 13

Question 6.
Now Collect information about various agents of seed dispersal from internet, your school library or by observing your surroundings. Make a Scrap book with pictures and your illustrations. And fill the below table with at least three examples each.

Agents of dispersal	Name of the seeds/fruit
Wind	Calotropis. Milk weed, Dandelion, Maple
Water	Coconut, Lotus, Water Lily
Animals	Guava, Tomato, Seeds of grass plants
Bird	Neem, Thorn apple, Cucumber, Achyranthus
Man	Sugarcane, Wheat, Pulses
Any other	Bhendi, Mustard, Kanakambaram

SCERT AP 7th Class Science Study Material Pdf 9th Lesson Heat, Temperature and Climate Textbook Questions and Answers.

AP State Syllabus 7th Class Science 9th Lesson Questions and Answers Heat, Temperature and Climate

7th Class Science 9th Lesson Heat, Temperature and Climate Textbook Questions and Answers

Improve Your Learning

I. Fill in the blanks.

1. Doctor uses ______ thermometer to measure the human body temperature.
2. The best liquid for thermometer is _____
3. The force applied by air on any surface in contact is called ______
4. The average weather pattern taken over a long time is called the _____ of the place
5. The amount of water vapour present in the air is called _____
Answer:
1. clinical
2. mercury
3. air pressure
4. climate
5. humidity

II. Choose the correct answer.

1. A student observe day-to-day conditions of the atmosphere on three consecutive days and recorded his observations. She wants to show the data using a graph. Which graph is suitable for her?
a) climate graph
b) weather graph
c) temperature
d) humidity graph
Answer:
b) weather graph

2. Conduction of heat takes place in
a) metals
b) liquids
c) gases
d) air
Answer:
a) metals

3. Average human body temperature is
a) 0°C
b) 20°C
c) 37°C
d) 100°C
Answer:
c) 37°C

4. Number of divisions in Fahrenheit scale
a) 180
b) 100
c) 50
d) 200
Answer:
a) 180

III. Matching.

A) Melting point of ice	1. mercury
B) Precipitate	2. barometer
C) Air pressure	3. 100°C
D) Boiling point of water	4. 0°C
E) Metal used in thermometer	5. rain gauge
	6. alcohol

Answer:

A) Melting point of ice	4. 0°C
B) Precipitate	5. rain gauge
C) Air pressure	2. barometer
D) Boiling point of water	3. 100°C
E) Metal used in thermometer	1. mercury

IV. Answer the following questions.

Questions 1.
What are similarities and differences between the laboratory thermometer and the clinical thermometer?
Answer:

Laboratory thermometer	Clinical thermometer
Differences:
1. Laboratory Thermometer is used in school labs, industries etc. to measure temperature.	1. Clinical Thermometer is used in hospitals to measure the temperature of the human body.
2. It has nd kink that prevents the mercury from flowing back into the bulb.	2. It has a kink that prevents the mercury from flowing back into the bulb.
3. Level of liquid may rise or fall after taking reading.	3. Level of liquid not changes after taking reading.
4. It has reading from -10 to 110° C (may vary)	4. It has reading from 35-42T & 95-108°F (may vary)
5. It is used to measure the tempera-ture of substances, weather etc.	5. It is used to measure the temperature of human body.
6. It is longer in size.	6. It is shorter in size.
7. It can measure higher temperatures.	7. It can measure lower temperatures
Similarities:
1. This is used to measure the temperature.	1. This is used to measure the temperature.
2. This is worked on the principle of expansion of substances by heat.	2. This is worked on the principle of expansion of substances by heat.
3. It is made with glass and has a bulb.	3. It is made with glass and has a bulb.

Question 2.
Draw the diagram of a clinical thermometer and label its parts.
Answer:

Question 3.
Give two examples for conductors and insulators each.
Answer:
Example for conductors:
Aluminum, iron and copper etc.

Example for insulators:
Water, air, clothes, glass, cork, plastic, wood etc.

Question 4.
Buchhanna thinks that the concepts • weather and climate are the same. Do you agree with him? Justify your answer.
Answer:
I do not agree the Buchhanna’s statement.

1. The day-to-day variations in the components like temperature, humidity, rainfall, wind speed are called weather. But, the average weather pattern taken over a long period, say 25 years or more is called the climate of the place.
2. Weather keeps on changing and changes are very fast too. But, climate of a place remains unchanged for a long period Of time.
3. Rapid changes occur in weather. But no rapid changes occur in climate.
4. Weather affects our daily life. But climate affects our lifestyle.
5. Weather gives the information about atmospheric conditions in a specific area and time. But, climate gives for a long time of period.

Hence, weather and climate are not the same.

Question 5.
Prepare two questions for a questionnaire for “farmers on climate change”.
Answer:
a) What type of climate changes do you observe in last ten years?
b) What changes have been made in the cultivation of crops due to climate changes?

Question 6.
Give two precautions to be taken while using a clinical thermometer?
Answer:

1. Wash the thermometer with water or an antiseptic solution before and after use.
2. Before use, the level of mercury should be less than 35°C, otherwise shake it.
3. Don’t touch the bulb while taking reading.
4. Handle the thermometer carefully, because it is a glass ware.
5. Take the reading after increasing of the mercury level is stopped.

Question 7.
Define conduction. Explain the process of transfer of heat by conduction with your own examples.
Answer:
1) The process of transfer of heat from hotter to colder end through the conductor is called conduction. This mode of transfer of heat happens more in solid conductors.

2) Example 1:
It takes some time for the heat to reach the end of the spatula placed in the cooking vessel. The heat from cooking vessel transfers to the end of the spatula gradually. This type of heat transfer is called conduction.

3) Example 2:
The edges of the steel plate with burning coal burn our hand while holding it. Here the heat transfers from the middle of the plate to the edges gradually.

4) Example 3:
If we put a needle by holding it in the candle flame, it causes burn to our hand. It is due to conduction of heat.

Question 8.
What are the measuring components of weather and explain about them?
Answer:
Maximum and minimum temperature of a day, air pressure, rainfall, wind speed and humidity are called measuring components of weather.

1) Maximum and minimum temperature of a day:
Maximum and minimum tempera-ture of a day are the highest and lowest temperature recorded respectively during a day. Six’s maximum and minimum thermometer is one of the meteorological in-struments used to measure maximum (highest) and minimum (lowest) temperatures of a place in a day.

2) Air pressure:
The force applied by air on any surface in contact is called “air pres-sure”. Air pressure is measured in height of mercury level in centimeters and it is measured with a barometer.

3) Rainfall:
The amount of water falling in rajn within a given time and area is called Rain fall. Rainfall is measured in millimeters by using a rain gauge.

4) Wind speed:
Wind move is caused by difference in the air pressure in two places. The speed of wind can be measured using a device called an anemometer.

5) Humidity:
The water vapour present in the air is called humidity Hygrometer is used to measure humidity in air and it is expressed in grams per cubic meter.

Question 9.
Explain an activity to show that “air experts pressure”?
Answer:

1. Take an empty bottle and a balloon.
2. Insert the balloon into the bottle.
3. Stretch the balloons over the opening of the bottle as shown in the figure.
4. Now try to blow air into the balloon inside the bottle.
5. But it is not easy to blow air when it is inside the bottle.
6. There is some force inside the bottle stopping you to do so.
7. This is because the force applied by the air inside the bottle.
8. The force applied by air on any surface in contact is called “air pressure”.

Question 10.
Explain the construction and working of six’s maximum and minimum thermometer?
Answer:

1. Six’s maximum and minimum thermometer is one of the Meteorological instruments used to measure maximum (highest) and minimum (lowest) temperatures of a place in a day.
2. James Six invented this thermometer in 1780.
3. It has a cylindrical ‘Bulb A’, and ‘Bulb B’ connected through a ‘U-shaped tube’ con-taining mercury.
4. Bulb A contains alcohol, and bulb B c’ontains alcohol and its vapours.
5. When the temperature increases, the alcohol in the bulb A expands and pushes the mercury in the U tube, this makes indicator N to move up.
6. This indicates the maximum temperature of the day.
7. When the temperature decreases, alcohol in the bulb A contracts and pulls the mercury back. This makes indicator M to move up.
   
8. This indicates the minimum temperature of the day.
9. After taking readings the indicators M and N are brought to their original places by using a magnet.

7th Class Science 9th Lesson Heat, Temperature and Climate InText Questions and Answers

7th Class Science Textbook Page No. 35

Question 1.
Mention the terms used in the conversation?
Answer:
Heat, cold, weather, temperature, minimum temperature.

Question 2.
What is the difference between Heat and Temperature?
Answer:
Heat flows from a body of high temperature to a body of low temperature . The degree of hotness or coldness is called temperature.

Question 3.
What is meant by climate of a place?
Answer:
The average weather pattern taken over a long period, say 25 years or more, is called the climate of a place.

Question 4.
Which form of energy help us to cook rice?
Answer:
Heat energy.

Question 5.
Which energy turns the water into vapour, while boiling?.
Answer:
Heat energy.

Question 6.
Why do you feel the heat when you hold a cup of warm milk to drink?
Answer:
We feel hot when heat energy flows from milk to our body. Here we gain heat energy from milk.

Question 7.
Why do you feel cool when you drink a glass of lassi?
Answer:
We feel cool, when heat energy flows from our body to lassi. Here, we lose heat energy.

7th Class Science Textbook Page No. 36

Question 8.
What determines the direction of heat flow?
Answer:
Heat flows from a body of higher temperature to a body of lower temperature. This direction is determined by temperature.

Question 9.
Have you heard about temperature, when you suffer from fever?
Answer:
Yes, I have.

Question 10.
What is temperature?
Answer:
The degree of hotness or coldness is called temperature.

Question 11.
What are the differences between heat and temperature?
Answer:

Heat	Temperature
1. Heat is a form of energy	It is the degrees of hotness or coldness.
2. It is measured in joules	It is measured in kelvin
3. It has the ability to do work.	It can be used to measure the degree of heat.
4. It flows from hotter bodies to colder bodies.	It increases with increase of heat and decreases with decrease of heat.

7th Class Science Textbook Page No. 37

Question 12.
Why are cooking utensils made of metals while their handles are made of plastic or wood?
Answer:

1. Some materials allow heat through them, this property is called conductivity.
2. We use metals to make cooking vessels because they allow heat through them.
3. We use material which do not allow heat to pass through as handles.
4. So, cooking utensils made of metals while their handles are made of plastic or wood.

7th Class Science Textbook Page No. 38

Question 13.
How does conductors transfer heat energy through them?
Answer:
Heat is transferred in the conductors from one end to another end by the mode of conduction.

Question 14.
How does water transfer heat energy from one place to another?
Answer:
Water transfers heat energy in the mode of convection.

Question 15.
How is heat energy transferred from the Sun to the Earth?
Answer:
Heat energy transferred from the Sun to the Earth in the mode of radiation.

Question 16.
Many times, Karthik observed that the handle of the spoon becomes hot when it is left for some time in hot oil, hot curry, hot tea or hot milk. Can you guess why does it happen? What is this process called?
Answer:
This is because heat is transferred from one end to another end by the mode of conduction.

7th Class Science Textbook Page No. 39

Question 17.
We know, water is a poor conductor of heat. But, when we heat water on a stove to take a bath, how does the surface of the water get heated?
Answer:
This happens due to the transfer of heat by a mode called convection.

7th Class Science Textbook Page No. 40

Question 18.
What happens if there is no medium (solid, liquid, gaseous substances) to transfer heat between two objects or two places?
Answer:
Heat transfers in the form of waves from one place to another, if there is no medium like solid, liquid, gas.

Question 19.
Recollect the conversation between the three friends Rafi, John, and Satyanarayana at the fire place and can you guess how does the heat energy transfer from the fire place to their bodies?
Answer:
This is because of heat transfer in the form of waves from one place to another.

Question 20.
How does a thermal scanner work, without being in contact with the human body?
Answer:
The thermal scanner receives the heat in the form of radiation to measure our body temperature.

Question 21.
Which instrument can control the transfer of heat (loss of heat)?
Answer:
Thermos flask can control the transfer of heat (loss of heat) and retain hotness of tea for a few hours.

Question 22.
How can we use Thermos flask to stop all modes of heat transfer?
(OR)
Do you know how Thermos flask works?
Answer:

1. Thermos flask has a two layered glass container and the air between these layers is removed to create a vacuum.
2. The inner silver coating protects the contents (tea, coffee, milk) poured in the flask from losing heat through radiation.
3. As there is no medium between the walls of the flask. Neither conduction nor con-vection of heat takes place.
4. As a result, heat is not transferred outside the flask so it is retained inside the flask for a few hours.

7th Class Science Textbook Page No. 41

Question 23.
Is it possible to keep the hotness of tea in flask forever?
Answer:
No, gradually a little amount of heat is lost from the lid by convection currents and a small amount of heat by conduction through the glass. Therefore, the tea does not retain heat for a long time or forever.

Question 24.
What changes can we observe in the size of material when it transfers heat energy?
Answer:
We can observe enlarging in the size of material when it transfers heat energy. This is due to increase in the energy of particles present in the substance.

Question 25.
Why are small gaps left between rails in railway tracks?
Answer:

1. Particles of substances occupy more space when they get heated.
2. In the hot days rails of the railway tracks enlarge (expand) due to heat energy.
3. It causes damage to the rails.
4. So, small gaps are left between rails in railway tracks.

Question 26.
What change occurs to the level of mercury in thermometer when it is kept in the mouth of a person suffering from fever?
Answer:
The level of mercury in thermometer increases when it is kept in the mouth of a person suffering from fever. This is due to expansion of mercury on heating.

Question 27.
Why does puri swell when it is put in hot oil?
Answer:
Puri swells when it is put in hot oil, because water in the substance is expanded in the hot oil.

Question 28.
What happens when you heat a piece of metal?
Answer:
When you heat a piece of metal it expands on heating.

Question 29.
Is there any change in the shape and size of a metal?
Answer:
Yes, shape and size changes in the expansion on heating a metal.

7th Class Science Textbook Page No. 42

Question 30.
Do the liquids also expand on heating as solids?
Answer:
Yes

Question 31.
Do gases also expand on heating like solids and liquids?
Answer:
Yes

Question 32.
What happens when air is heated?
Answer:
Gases (Air) expands on heating and occupies more space.

7th Class Science Textbook Page No. 43

Question 33.
How can we use expansion of liquids?
Answer:
We can make devices like thermometers by using the property of expansion of liquids on heating.

Question 34.
What device we use to measure the temperature of a substance and how it works?
Answer:
Thermometers are used to measure temperature, this works on the expansion of liquids (mercury).

Thermometer – roleplay (personification)

Question 35.
How are you?
Answer:
I am fine.

Question 36.
Do you know me?
Answer:
Yes, I know you. You are a thermometer.

Question 37.
Have you ever seen me?
Answer:
Yes, I have seen in my home and hospital.

Question 38.
Try to recall how I look like?
Answer:
You are made of a narrow glass tube with thick walls which is closed at one end and You have a bulb of mercury or alcohol on the other end.

Question 39.
Do you know why mercury or alcohol is used in me?
Answer:
Mercury and alcohol have the best properties to measure temperature.

7th Class Science Textbook Page No. 44

Question 40.
Do you ever observe any marks on Alcohol thermometer? Can you guess what are they?
Answer:
Yes, I observed. Those marks are called scales.

7th Class Science Textbook Page No. 45

Question 41.
How can we use laboratory and clinical thermometers?
Answer:
Using of a laboratory thermometer:

1. Place the mercury bulb of the thermometer in a liquid, so that the bulb immerses in it.
2. Wait for some time till the mercury level shows a constant reading.
3. And take the reading at the level of the mercury.

Using of a clinical thermometer:

1. Wash the clinical thermometer properly with an antiseptic solution.
2. To lower the mercury level, hold the thermometer firmly and give some jerks.
3. Ensure that it falls below 35 °C.
4. Now place the bulb of the thermometer under your friend’s tongue.
5. After one or two minutes, take the thermometer out and note the reading.
6. This is your body temperature.
7. Don’t hold the thermometer by the bulb while reading it.

7th Class Science Textbook Page No. 46

Question 42.
What is your friend’s body temperature?
Answer:
98.4°F. (write your friend’s body temperature)

Question 43.
Why are armpit or part below tongue selected to record temperature?
Answer:
The clinical thermometer is used to determine the temperature of the interior of the body. The part under the tongue is the most accessible area to get accurate interior temperature. So, temperature is taken underneath the tongue. But it is difficult and inconvenient for kids to hold the thermometer under their tongue. So armpit will be used for kids to take body temperature, even though it is not accurate.

Question 44.
Can you tell why smoke always rises up?
Answer:
Smoke and hot air moves up because it expands and becomes lighter.

Question 45.
Why do we have ventilators and exhaust fans on the upper parts of the wall?
Answer:
Smoke and hot air moves up because it expands and becomes lighter. That’s why we have ventilators and exhaust fans on the upper parts of the wall to exhaust hot air and smoke from a room.

Question 46.
What happens at a place, where air expands and rises up?
Answer:
When air expands and rises up it creates a low pressure area.

Question 47.
Who occupies that place which is vacated by hot air?
Answer:
The air high pressure from surrounding to move and occupy that place.

Question 48.
What makes the cooler air come into that place?
Answer:
Low air pressure.

7th Class Science Textbook Page No. 47

Question 49.
Have you ever seen high speed winds blowing over the roofs of houses?
Answer:
Yes.

Question 50.
Is there any relation between these components and the weather of a place?
Answer:
The measurements of components like wind speed, rainfall, temperature etc. in a certain-time and location is called weather.

Question 51.
Do we have any other components of this kind?
Answer:
Yes, humidity is the other components of this kind.

7th Class Science Textbook Page No. 48

Question 52.
Where does this evaporated water go?
Answer:
All the evaporated water from different water bodies go into air.

Question 53.
Do you know what we call this evaporated water present in air ?
Answer:
This water vapour present in the air is called humidity.

Question 54.
What is the role of humidity in sunstroke?
Answer:

1. Evaporation of sweat from our body makes us cool to maintain our body temperature.
2. In summer, the humidity of air is high.
3. Due to high humidity and temperature, it becomes difficult to evaporate the sweat from our body to cool it down.
4. But still our body losses water.
5. High temperatures, along with humidity sometimes may cause heat stroke or sunstroke.

7th Class Science Textbook Page No. 49

Question 55.
Do all the days have the same values of components of weather?
Answer:
No. All are not the same on all days. This causes variations in atmospheric conditions.

Question 56.
How can we get information of weather at a place?
Answer:
We can get details of weather from weather reports and you can see these symbols on television, newspapers and in weather forecasting.

Question 57.
Have you ever seen the symbols shown in the figure?
Answer:
Yes, I saw it in TV and newspapers.

7th Class Science Textbook Page No. 50

Question 58.
How can we present these components of weather, more effectively?
Answer:
We present these components of weather; more effectively by tabulating these values and by drawing these graph.

Question 59.
Do the climate of a place changes like weather?
Answer:
The climate of a place does not change like weather. Climate of a place remains unchanged for a long period of time.

Question 60.
What are the measuring components of climate?
Answer:
Temperature, air pressure, rainfall, wind speed and humidity are the measuring components of climate.

Question 61.
Is weather and climate are one and the same?
Answer:
Not the same.

7th Class Science Textbook Page No. 51

Question 62.
What happens if the components of climate changes abnormally?
Answer:
The abnormal variation in the components of climate is called climate change. These variations may affect all parts of the world.

Think & Respond

7th Class Science Textbook Page No. 38

Question 1.
When two ice cubes are placed on wood and aluminium objects with same size which ice cube will melt faster, why?
Answer:

1. The ice cube placed on the aluminium object will melt faster.
2. Because of aluminium is a good conductor of heat.
3. Transfer of heat takes place quickly.
4. But wood is a poor conductor of heat and transfer of heat takes place slowly.

Question 2.
Why do animals that live in colder regions have more fur and thick fat layer under the skin?
Answer:

1. Animals that live in colder areas have to protect their bodies against extremely cold environmental conditions.
2. Their bodies cannot withstand such cold climates.
3. So, they have thick white fur on their body.
4. This provides an additional layer over their skin.
5. Thick white fur acts as insulator of heat and stops the heat transfer from body to outside and vice versa.
6. Animals in colder regions have thick layers of fat, because fat acts as an insulator and doesn’t let their body heat escape, which helps them survive in such extreme temperatures.

Question 3.
Why do we wear woolen clothes in winter?
Answer:
As wool is a very good insulator and a poor conductor of heat, woolen clothes keep the body warm and protect it from the cold winds.

Question 4.
Why do most of the desert animals live in burrows (inside soil)?
Answer:
Reptiles, insects and most of the desert animals live in burrows below the surface of the soil or sand to escape the high temperatures at the desert surface.

7th Class Science Textbook Page. No. 39

Question 5.
Why are the Upper layers of water in a pond or a lake hotter than the lower layers during the hot summer?
Answer:

1. The heat from the sun is reached to the Upper layers of the lakes first.
2. We know that heat transfers in convectional mode in water. .
3. Convectional currents take more time to reach the lower layers as there are in deep.
4. This means it takes more time to transfer of heat to the bottom of the lake or pond.
5. The water of the surface layer is evaporated by absorbing heat and does not heat up quickly.
6. As a result heat does not reach the lower layers of the lake. It is another reason.

7th Class Science Textbook Page No. 41

Question 6.
Why the electric power lines (wires) are held loose on poles?
Answer:

1. Wire is made up of metal. So, it expands on heating and contracts on cooling.
2. If the wire is fixed tightly with maximum tension between two poles, may cut due to contraction on cooling conditions in winter,
3. So, the electric power lines (wires) are held loose on poles to minimize the tension in the wires.

Question 7.
Why are rollers kept under the beams of metal bridges?
Answer:

1. Roller supports are commonly located at one end of long bridges.
2. This allows the bridge structure to expand and contract with temperature changes and prevents damage.

DO THIS (Page No. 49)

Collect the information about symbols of the weather report and display them in
the classroom.
Answer:

Activities and Projects

Question 1.
Prepare a report by collecting different types of materials in your surroundings and classify them into good and poor conductors based on their conductivity.
Answer:

Question 2.
Visit a veterinary doctor and find out the normal body temperature of domestic animals and birds.
Answer:

Question 3.
Visit the nearby Tahsildar office or meteorological department office and observe different instruments which are used to measure components and record your ob-servations.
Answer:

Instrument	Measuring component
1. A thermometer	air temperature
2. A barometer	atmospheric pressure
3. An anemometer	wind speed and the direction the wind is blowing
4. A hygrometer	the relative humidity at a location
5. A ceilometer	determine the height of a cloud base and the aerosol con-centration within the atmosphere.
6. Adisdrometer	the drop size distribution and velocity of falling hydrometers.
7. Rain gauges	the precipitation which falls at any point on the Earth’s landmass.

Question 4.
Measure the body temperature of atleast 10 of your Mends and prepare a report.
Answer:

Question 5.
Note down maximum and minimum temperature of five consecutive days from today by using 6 minimum and maximum thermometer.
Answer:

Activities

Activity – 1

Question 1.
How do you prove that heat is a form of energy?
(OR)
Write an activity to explain the heat concept.
Answer:

1. Take a glass bottle and a one-rupee coin.
2. Wet the mouth of the bottle and place a coin on it.
3. Rub your hands together to produce heat.
4. Now place them around the bottle.
5. Observe the coin. It moves.
6. Reason:- the movement in the coin is caused by heat supplied to the bottle from your hands.
7. Conclusion:-So, we can say heat is a form of energy.

Activity – 2

Question 2.
How do you show the degree of hotness or coldness through an activity?
(OR)
write an activity to understand the concept of temperature.
Answer:

1. Take some Iuke-warm water in one glass and hot water (which you can bear) in another glass.
2. Touch them and feel the hotness of both.
3. Take a glass of cool water and cubes of ice in another glass.
   
4. Touch them feel the coldness of both.
5. You will feel hot water is hotter than Luke warm water and ice is cooler than cool water.
6. The variations of hotness, coldness can be termed as degree of hotness and coldness.
7. The degrees of hotness or coldness is called “Temperature”.

Activity – 3

Question 3.
Write an activity to understand the thermal conductivity.
(OR)
Write an activity to prove that the good conductors allow the heat to pass through them and insulators do not.
Answer:

1. Take a glass beaker and pour some hot water in it. mmmd
2. Now dip a metal spoon, plastic spoon, wooden stick, glass rod, and long iron nail into it as shown in the figure.
3. Wait for few minutes and touch each and every object.
4. Fill in the table given below.

Objects that allows heat	Objects that do not allow heat
Metal spoon	Plastic spoon
Long iron nail	Wooden stick
Glass rod K

From this activity, you will know that good conductors allow the heat to pass through them and insulators do not.

Activity – 4

Question 4.
Write an activity to show that heat is transferred from one end to another end by the mode of conduction.
(OR)
Write an activity to show the conduction in metals.
Answer:

1. Take a metal spoon and fix four pins with candle wax on it at equal distances from each other.
2. Now place one end of this spoon with pins in a flame of candle holding the other end of it with a piece of cloth.
3. Observe for a while. Record your observations.
4. You will observe the dropping of pins one after another from the flame end of the spoon.
5. This is due to the transfer of heat from the end kept in the flame (hotter end) towards your hand (colder end) through a spoon (metal).
6. This process of transfer of heat from hotter to colder end through the conductor is called conduction. This mode of transfer of heat happens more in solid conductors.

Activity – 5

Question 5.
How can you prove that heat is transmitted by mode of convection in liquids.
(OR)
Write an activity to show the convection in liquids.
Answer:
Aim: To demonstrate the convection of heat in liquids.

What you need:
Round bottomed flask, stand, water, potassium permanganate, straw, candle / spirit lamp.

How to do:

1. Take a round bottomed flask and fix it to a stand.
2. Now fill this flask with water.
3. Wait for some time till this water remains still.
4. Gently place some crystals of potassium permanganate in the bottom of the flask by using a straw.
5. Now slowly, heat the flask with a lighted candle or spirit lamp and observe carefully.

What you see:

1. After a few minutes the crystals of potassium permanganate dissolve in water and the coloured water will move up.
2. This is because the water at the bottom gets heated and expanded.
3. Therefore, water becomes light and moves to the top.
4. From the top, cool water comes down through the sides of the flask because it is heavier than hot water.
5. This process will continue further.
6. So, heat gets transferred from one place (bottom) to another place (top).

What you learn:

This process of transfer of heat from source of heat to surface by the motion of particles is called “convection of heat”. Here heat is transferred by means of currents called convectional currents. In liquids and gases heat is transmitted by mode of convection of heat.

Activity – 6

Question 6.
How can you prove that solid expands on heating and contracts on cooling?
Answer:

1. Take two blocks of wood of same heights.
2. Take a cycle spoke.
3. Fix one end of the rod to a wooden block with the help of plastic tape, so that it will not move.
4. Place the free end of the cycle spoke on another wooden block.
5. Take a needle and poke straw to it.
6. Place this needle between the spoke and wooden block.
7. Place 4 or 5 candles or divas under the metal rod between the blocks and light them.
8. Observe the straw carefully.
9. You will observe movement in the straw. The needle rolls on the second block of wood because of the expansion of the cycle spoke.
10. Now remove the candles or divas and observe.
11. If we remove the candles the needle rolls back causing movement in the straw oppo-site to the previous motion.
12. From this activity we can say solid expands on heating and contracts on cooling.

Activity – 7

Question 7.
How can you prove that liquids expands on heating?
Answer:

1. Take test tube and fill it with coloured water.
2. Fix a capillary tube through a rubber cork and mark the level of water on the tube.
3. Now put test tube in hot water and observe the level of water in tube.
4. Observe the difference in the level of water after heating.
5. You will observe raising in the level of water in the tube while heating
6. Stop heating and observe change in the level of water again.
7. The level of water in the tube lowering while cooling.
8. From this you can say that liquids expands on heating and contracts on cooling. (You can use injection bottle instead of test tube and empty refill instead of capilary tube.)

Activity – 8

Question 8.
How can you prove that air expands on heating? What happens when air is heated? Explain with an activity. |i
Answer:

1. Take a bottle with a small neck.
2. Attach a balloon at the neck of the bottle.
3. Place the bottle in a vessel containing water.
4. Heat the vessel and observe the size of the balloon care* fully.
5. You observe that the balloon will get inflated, because the air inside the bottle gets heated up and expands.
6. Now stop heating the bottle and remove it from hot water.
7. If needed keep it in cold water and observe the size of the balloon.
8. On cooling, you will observe deflation of the balloon.
9. Here air contracts on losing heat.
10. This activity concludes Gases (Air) expands on heating and occupies more space.
11. They contracts on cooling and occupy less space.

Activity – 9

Question 9.
How can we use laboratory thermometers? Explain with an activity.
Answer:

1. Take two bowls.
2. Take cold water in one bowl and hot water in another bowl.
3. Place the mercury bulb of the thermometer in cold water so that the bulb immerses in it.
4. Wait for some time till the mercury level shows a constant reading.
5. Note down that reading.
6. Now place the thermometer in hot water and note down the tern- perature reading.
7. Note down the temperature of the given cold water.
8. Note down the temperature of the given hot water.

Activity – 10

Question 10.
How to use a clinical thermometer? Explain with an activity.
Answer:

1. Wash the clinical thermometer properly with an antiseptic solution.
2. To lower the mercury level, hold the thermometer firmly and give some jerks.
3. Ensure that it falls below 35°C.
4. Now place the bulb of the thermometer under your friend’s tongue.
5. After one or two minutes, take the thermometer out and note the reading.
6. This is your body temperature.
7. Don’t hold the thermometer by the bulb while reading it.
8. Note down the body temperature your friend.
9. The normal temperature of the human body is 37°C or 98.4°F.

Activity – 11

Question 11.
How can you explain with an activity, that “On heating, the air expands” occupying more space and becomes lighter?
(OR)
What happens to the air on heating? Explain with an activity.
Answer:

1. Take two empty paper cups of the same size.
2. Take a broomstick.
3. Hang the two cups in the inverted position from the two ends of the broomstick using thread.
4. Tie a piece of thread in the middle of the stick. Hold the stick by the thread, like a weighing balance.
5. Put a burning candle below one of the cups as shown in the figure and observe what happens.
6. We notice that the cup above the candle flame moves up.
7. As you already know the phenomenon of convection of heat, the same phenomenon works in air.
8. Here the air above the candle gets heated up, becomes lighter and rises up.
9. This rising air pushes the paper cup.
10. On the other hand, the air under the second paper cup remains the same.
11. So, we say that “On heating, the air expands” occupying more space and becomes lighter.

Activity – 13

Question 13.
How do you show that the moving air creates low pressure with an activity?
Answer:

1. Take a glass and keep a postcard on it.
2. Wave your notebook above the post card to displace the air just above the postcard.
3. Observe the post card.
4. When we move our note book, there is a movement of air.
5. The moving air creates low pressure.
6. Hence the postcard lifts up due to the higher pressure on the card from air inside the glass.

Activity – 14

Question 14.
Collect the weather reports of any place (near your village) of the last 7 days from a newspaper or television. Record the information in the table given below.

Answer the following questions.
1. What are the measuring components of weather?
Answer:
Maximum and minimum temperature of a day, air pressure, rainfall, wind speed and humidity are called measuring components of weather.

2. What is your observations? Do all the days have the same values of components of weather?
Answer:
1 observe that, some components in the table may be the same for some days. But, all are not the same on all days. This, causes variations in atmospheric conditions.

Activity – 15

Question 15.
Classify the following sentences and write in the table given below.
1) It keeps on changing.
2) Typical weather in a region for a long period of time.
3) It affects our lifestyle.
4) It remains constant for 25 years or more.
5) It affects our daily life.

Weather	Climate
1. It keeps on changing.	Typical weather in a region for a long period of time.
2. Atmospheric conditions in specific area and time.	It affects our lifestyle.
3. It affects our daily life.	It remains constant for 25 years or more.

SCERT AP 7th Class Science Study Material Pdf 6th Lesson Electricity Textbook Questions and Answers.

AP State Syllabus 7th Class Science 6th Lesson Questions and Answers Electricity

7th Class Science 6th Lesson Electricity Textbook Questions and Answers

Improve Your Learning

I. Fill in the blanks.

1. Longer line in the symbol for a cell represents its ____ terminal and the shorter line represents ____ terminal.
2. Iron box works based on ____ effect of electric current.
3. The symbol for open switch is _______ .
4. The combination of two or more cells is called a ____
5. Expand MCB ____
Answer:
1. Positive, Negative
2. heat
3.
4. battery
5. Miniature Circuit Breaker

II. Choose the correct answer.

1. When cells are connected in series, it has
a) Single loop connection
b) Two loops
c) Many loops
d) None
Answer:
a) Single loop connection

2. Four bulbs are connected in parallel. When one bulb is removed then the remaining bulbs are
a) Put off
b) Continuously glowing
c) Blinking
d) None
Answer:
b) Continuously glowing

3. Statement 1: Generation of heat due to electric current is known Magnetic effect of electricity.
Statement 2 : An electromagnet works on magnetic effect of Electricity.
a) Both statements are true.
b) Both statements are false.
c) Statement 1 is true, Statement 2 is false.
d) Statement 1 is false, Statement 2 is true.
Answer:
d) Statement 1 is false, Statement 2 is true.

4. Ramu’s house has five 60W bulbs. If they used all the bulbs for 5 hours. Then the power consumed by him

a) 1500 KWH
b) 0.3 KWH
c) 70 KWH
d) 1.5 KWH
Answer:
d) 1.5 KWH

5. Which of the following works on the basis of heating effect of electric current?
a) Electric Crane
b) Electric Lift
c) Escalator
d) Hair drier
Answer:
d) Hair drier

III.Matching

A) MCB	1. Safety device used in electric current
B) Fuse	2. Two or more cells joined together
C) Battery	3. Compact Fluorescent Lamp
D) Cell k	4. Miniature Circuit Breaker
E) CFL	5. Converts chemical energy into electrical energy
	6. Useful for opening and closing circuit

Answer:

A) MCB	4. Miniature Circuit Breaker
B) Fuse	1. Safety device used in electric current
C) Battery	2. Two or more cells joined together
D) Cell k	5. Converts chemical energy into electrical energy
E) CFL	3. Compact Fluorescent Lamp

IV. Answer the following questions.

Question 1.
Why are bulbs in series put off when a bulb is removed from it?
Answer:

1. In series connection electricity has only one path.
2. If a bulb is removed from the series connection of bulbs, the circuit becomes open.
3. So, remaining bulbs are put off as the circuit open.

Question 2.
Read the following riddles and answer them.
1. I am used to close-or open the circuit. Who am I?
2. I will give you light. Who am I?
3. I convert chemical energy into electrical energy. Who am I?
4. Without me you cannot connect the electrical components. Who am I?
Answer:

1. Switch
2. Bulb
3. Cell
4. Connecting wires

Question 3.
Give examples for electric appliances which work on the property of heat effect of electricity.
Answer:
Examples for electric appliances which work on the property of heat effect of electricity:

1. Electric heater
2. Electric iron box
3. Soldering gun
4. Electric kettle
5. Electric rice cooker

Question 4.
A cell, 5 bulbs and a switch are connected in a circuit but bulbs are not glowing. Write the possible reasons for this.
Answer:
Possible reasons:

1. May be connected a dysfunctional or less voltage cell.
2. May be switch in off position.
3. Wires may be cut any where or not properly connected.
4. At least one of the bulbs may be damaged (If they are connected in series).
5. All the bulbs may be damaged. (If they are connected in parallel)

Question 5.
Describe the process to prepare an electromagnet.
Answer:
1) Take an iron nail.
2) Wound the insulated copper wire tightly around the nail.
3) Connect the two ends of the coiled copper wire to a battery and a switch in series connection.
4)
5) Place some pins near the iron nail.
6) Now switch on the circuit.
7) Observe that all pins cling to the end of the iron nail.
8) This indicates coiled copper wire around nail acts as magnet when electricity passes through it.
9) It means the coiled copper wire around the nail acts as an electromagnet.
10) Now switch off the circuit.
11) Observe that all pins fall from the iron nail.
12) Hence, we can say that the coiled copper wire does not act as a magnet when no electricity passes through the circuit.

Question 6.
Draw the symbols for the following.
A) Bulb
B) Cell
C) Battery
D) Open Switch
Answer:

Question 7.
Draw a circuit diagram of electrical components in a sequence by using cell, bulb, switch is off mode and connecting wires.
Answer:

Question 8.
How do you appreciate the role of magnetic effect and heating effect in our daily life?
Answer:

1. The production of heat due to the flow of electricity through a wire is called heating effect of electricity.
2. We are using many home appliances like electric iron boxes, electric cookers, electric heaters, geysers, hair dryers which work on the principle of heating effects of electricity.
3. The above said home appliances contain heating elements which produce heat.
4. The production of magnetic force due to the flow of electricity through a wire is called magnetic effect of electricity.
5. Loud speakers, MRI machines, generators, metal detectors, mobile phones, mixer grinders, electric fans, electric bells, electric motors etc.; work based on the magnetic effect of electricity.
6. In this, way, heating and magnetic, effects of electricity are used in medical, automobile, industrial, agricultural etc., fields and also in homes.
7. The devices and home appliances have made our lives more comfortable.
8. Hence, I appreciate the role of magnetic effect and heating effect^ in our daily life.

Question 9.
Prepare some slogans to create awareness on wastage of electricity.
Answer:

1. Save electricity – Save money.
2. Turn off the lights, before leaving.
3. Today’s wastage is tomorrow’s shortage.
4. The less you burn, the more you earn.
5. Save power – Save nation.
6. Be polite – turn off the light.
7. When the sun is bright – say no to tube light.
8. Energy is precious – use 5 star appliances.
9. Leave filament bulbs – Use LED’S
10. Less consumption of power – Leads more comforts in future.

Question 10.
Suggest first aid when a person suffers electric shock.
Answer:
First aid for electric shock :

1. If the shock is severe and the person is unconscious, give mouth to mouth artificial respiration.
2. Sometimes heart beat ceases, at that time keep your palms on his chest and press down and release until the heart beat is recovered. This is called Cardio Pulmonary Resuscitation (CPR).
3. Immediately take him to the hospital.

7th Class Science 6th Lesson Electricity InText Questions and Answers

7th Class Science Textbook Page No. 83

Observe the picture carefully.

Question 1.
What are the electric devices you find in the above picture?
Answer:
1) Bulb 2) Fan 3) TV.

Question 2.
List out the electric devices used in your homes.
Answer:
1) TV 2) Fans 3) CFL bulbs 4) LED bulbs 5) Tube light (LED) 6) Music system 7) Chargers 8) Refrigerator 9) Electric geyser 10) Vapourizer 11) Iron box 12) Calling bell 13) Mixie 14) Wet grinder 15) AC 16) Motor pump 17) Mosquito repellent.

7th Class Science Textbook Page No. 84

Question 3.
Why does a bulb glow when we switch it ON?
Answer:
When we switched ON the bulb electricity flows through the wire and makes the bulb to glow.

Question 4.
What do you observe inside the cell?
Answer:

1. Carbon rod with a metal cap.
2. Carbon powder.
3. Ammonium chloride paste.

Question 5.
Can we make a cell of our own?
Answer:
Yes, we can make a cell by using a zinc plate, copper plate, a small bulb, connecting wires, lemon or orange, crocodile clips.

7th Class Science Textbook Page No. 85

Question 6.
Do you know the type of cell is used in wrist watch?
Answer:
Button cells are used is wrist watches.

Question 7.
How many types of electric cells shown above are known to you?
Answer:
I know the dry cells, lithium cells, button cells and alkaline cells.

Question 8.
Where do we used dry cells?
Answer:
In our daily life we use dry cells in torch lights, wall clocks, radios etc.

7th Class Science Textbook Page No. 86

Question 9.
Does a bulb glow when switch is in off position? Why?
Answer:
When the switch is in off position, bulb does not glow. Because the circuit is opened.

7th Class Science Textbook Page No. 87

Question 10.
Among all these bulbs which bulb consumes less electricity?
Answer:

1. We can observe star symbols (power saving star rating) are marked on electrical appliances.
2. The number of stars on them indicates the energy efficiency of that device.
3. The electrical appliance with more stars consumes less electricity.
4. LED bulbs are more energy savers than other bulbs.

Question 11.
Is there any protection provided for electric devices in our house?
Answer:
Yes. The fuse is used to protect the electric devices in our house.

Question 12.
If there is a power failure only in your house. What do you check first?
Answer:
We will check the fuse first.

Question 13.
Have you seen the electric device shown in the figure. Where is it used?
Answer:

1. The electrical devices shown in the figure are fuses.
2. Fuses are used at meter board to protect the devices from excess flow of electricity.

Question 14.
Is there any other safety device which can be used as a fuse?
Answer:
Yes, MCB can be used as a fuse.

7th Class Science Textbook Page No. 88

Question 15.
Have you ever seen this component?
Answer:
Yes, I saw it. It is a MCB.

Question 16.
Which is a better safety device, electric fuse or MCB?
Answer:
MCB is better, when compared to electric fuse. There is no need to change it often. But wire in electric fuse has to be changed whenever it melts.

Question 17.
Do you know how to show the connections of the electric components in a circuit?
Answer:
Yes. We can show the connections of the electric components in a circuit by its symbols.

Question 18.
What electric components do you find in the figure?
Answer:

1) Switch 2) Bulb 3) Wire 4) Battery.

Question 19.
Is it possible to draw realistic electric components every time? Why?
Answer:

1. Drawing circuit diagrams with realistic components is difficult.
2. If the circuit is a bigger one with several components it is much more difficult.
3. To overcome this, standardized symbols of electric components are used to draw the circuit diagrams.

7th Class Science Textbook Page No. 89

Question 20.
Isn’t it so easy to draw like this?
Answer:
It is easy to draw a circuit by using symbols of electric components than realistic components. .

Question 21.
What difference do you find between circuit diagrams A and B?

Answer:

1. We observe that the bulb in circuit ‘A’ is not glowing and in circuit ‘B’ it is glowing.
2. We can also see the switch is in OFF mode in circuit diagram A and it is in ON mode in circuit diagram B.
3. Circuit diagram ‘A’ represents open circuit, where as circuit diagram ’B’ represents closed circuit.

7th Class Science Textbook Page No. 90

Question 22.
Is it possible to connect more than one bulb or one cell in an electric circuit?
Answer:
Yes, it is possible.

Question 23.
What happens if we connect more bulbs or cells in an electric circuit?
Answer:

1. There are two ways to connect more bulbs or cells in an electric circuit they are parallel and series connections.
2. In parallel connection electricity has more than one path where as in series connection only one path.
3. If the number of cells are connected in series the brightness of the bulbs enhanced where as in series the brightness of bulb remains same.

Question 24.
Have you observed a large number of bulbs used in decorations of marriage functions, festivals etc.?
Answer:

1. Yes, I have observed a large number of bulbs used in decorations of marriage functions, festivals etc.
2. All the bulbs are connected one after one that means in series.

Question 25.
What happens when we connect two cells and two bulbs in the same path?
Answer:

1. If we connect two cells and two bulbs in the same path, it is called series connection.
2. The brightness of the bulbs increased.

7th Class Science Textbook Page No. 92

Question 26.
Where can we observe these type of connections? (Series & Parallel)
Answer:

1. We can use series connection of cells in torch light, toys, remotes, wall clocks,radio etc.
2. We can use parallel connection of cells for a long – lasting battery life.

Question 27.
Do you know how several electric devices are connected in your home? Did you observe any pattern in their connections?
Answer:
If All the electric devices in our house are connected in parallel.

7th Class Science Textbook Page No. 93

Question 28.
Where can we observe these types of connection?
Answer:
We use series connection of bulbs for decoration purpose, parallel connection of bulbs in house hold connections.

7th Class Science Textbook Page No. 94

Question 29.
Naime the electrical devices used to produce heat?
Answer:
Electric iron box, electric heater, geyser, grills, electric cooker etc. are the electrical devices used to produced heat.

Question 30.
Have you ever used an iron box to iron your clothes? How does it produce heat?
Answer:

1. Electric iron box contains the coil of wire (filament) which produce heat, when electricity passed through it.
2. It is called heating effect of electricity.

Question 31.
Which electric appliances work on the principle of heating effect of electricity?
Answer:
1) Electric stove, 2) Electric room heater, 3) Electric iron box, 4) Electric kettle, 5) Electric cooker, 6) Water heater, 7) Geyser, 8) Hair dryer, etc. are working on the principle of heating effect of electricity.

7th Class Science Textbook Page No. 95

Question 32.
1) How does a fan work?
2) What makes the fan to rotate?
3) What is the principle involved in it?
Answer:

1. Fan works on the principle of magnetic effect of electricity.
2. The magnetic force, which is produced due to the flow of electricity through a wire (coil) makes the fah to rotate.
3. The principle, magnetic effect of electricity is involved in it.

7th Class Science Textbook Page No. 96

Question 33.
Which electric appliances work on the principle of magnetic effect of electricity?
Answer:
1) Electric fan, 2) Electric bell, 3) Electric motor, 4) Loud speaker, 5) MRI machines, 6) Generators, 7) Metal detectors, 8) Mobile phones, 9) Mixer grinders, etc. work on the principle of magnetic effect of electricity.

Question 34.
Have you seen the electric meter in your house? What do you find in the meter?
Answer:
I find reading of consumed electricity in units.

Question 35.
What does the term ‘one unit’ mean?
Answer:
1 unit = 1000 watt = 1 K.W.H.

Question 36.
How is the usage of electricity measured?
Answer:
Usage of electricity is measured in KWH (unit).

7th Class Science Textbook Page No. 98

Question 37.
What is an electric shock and when does it occur?
Answer:

1. An electric shock occurs when a person comes into contact with an electrical source.
2. Electricity flows through a portion of the body causing a shock.

Think & Respond

7th Class Science Textbook Page No. 85

Question 1.
Now a days we are using rechargeable torchlights, bulbs, mobile phones and fens. Think and discuss with your classmates about the working of these electric devices and the cells used in diem.
Answer:

1. A cell is made up of three parts, a cathode, an anode and an electrolyte (a chemical).
2. A cell works by connecting its stored chemical energy, into electrical power
3. One the electrolyte of the cell is used up it doesn’t work further in non – rechargeable cells (Alkaline cells).
4. Electrons (negative charges) travel from an anode to a cathode until the anode is considered empty or dead.
5. A rechargeable cell, a charger can reverse the electron flow again to restore at the anode. This is called charging.
6. This reversing process depends upon the electrolyte used in the cell.
7. Normal cells do not contain such type of electrolytes to reverse the charge.
8. But, the cells like NiMH (Nickel – Metal Hydride), Lithium – ion are capable of reversing the charge when charged it for number of times.
9. This type of rechargeable batteries are used in rechargeable torch lights, bulbs, mobile phones and fans.

7th Class Science Textbook Page No. 92

Question 2.
a) What happens if more cells are connected in a series?
b) Is there any restriction on the number of cells in a circuit for a given bulb?
Answer:
a) If more cells are connected in a series, voltage increases in the circuit. That means the strength of the current in the circuit increases.

b) When we will join lot of cells in a circuit, then the bulb will not be able to handle the large amount of energy supplied to it. Hence, the bulb may damage.

7th Class Science Textbook Page No. 95

Question 3.
Do all home appliances produce heat when electricity passes through them?
Answer:

1. Yes, all home appliances produce heat when electricity passes through them.
2. But the amount of heat produced depends on the material of conductor, such as length, thickness and nature of it.

7th Class Science Textbook Page No. 96

Question 4.
Is it possible to create permanent magnets using the magnetic property of electric current? Think and discuss with your classmates and make notes on this.
Answer:

1. Electromagnets are not permanent magnets because they lose the property of magnetism when the circuit is open.
2. A permanent magnet has a magnetic field all the time unless it is heated.
3. But electromagnet doesn’t retain its magnetism all the time, without current.

7th Class Science Textbook Page No. 98

Question 6.
Why don’t we use wet stick to push away a person when he get electric shock? Think and discuss with your friends.
Answer:

1. Wet stick contains some amount of water throughout it.
2. Water is a good conductor of electricity (ofcourse, pure water does not pass current).
3. If we touch the person to push away from the electric wire, the current passes through the water into our body.
4. It causes to get electric shock to us also.
5. So, we should not use wet stick to push away a person when he get electric shock.
6. We should use dry stick only to do that.

Activities and Projects

Question 1.
Collect any manual of electric equipment. Read the information in detail and answer the following questions.
A) When was it manufactured and how long can we use it?
B) How many stars are given to it?
C) Is it working on the basis of magnetic or heating effect?
Answer:
I Read the manual of a washing machine.
A) It was manufactured on 8^th March 2020.
B) It was given 5 stars.
C) It is working on the bases of both magnetic effect (motor) and heating effect (in built heater).

Question 2.
Find out the electric meter readings for 3 months in your house. Record your observations. Ask your teacher about how electricity bill is paid.
Answer:

Question 3.
Make a pamphlet on “Save electricity, don’t waste it”. Display it on the wall magazine?
Answer:

Question 4.
Collect last month’s electricity bills from your friends or neighbours houses and record the data. Advise them to change their ordinary bulbs with CFL bulbs. Again collect the electricity bilis of next month and observe the differences between the two bills. Discuss your observations with your friends and suggest better bulb.
Answer:
Observation sheet (Student Activity).

Conclusion :
After replacing ordinary bulbs with CFL/LED bulbs the consumption of electricity is reduced and Bill amount is saved.

Question 5.
If anyone around you has suffered an electric shock, collect the information along with their feelings and know about CPR. Record your observations in your note book and discuss with your friends.
Answer:
Observation sheet (Student Activity).

Activities

Activity – 1

Question 1.
If you open a dry cell, what do you observe?
(OR)
What do you observe inside the cell?
(OR)
Explain the structure of a cell with an activity.
(OR)
Describe the constru-ction of a dry cell.
(OR)
Describe the various components in a dry cell and their functions.
Answer:

1. Take a cell used in torch light and open it with the help of your teacher.
2. The cell consists of a container made of zinc metal. The container works as the negative terminal (- ve).
3. A carbon rod with a metal cap works as a positive terminal 0 ve>
4. The positive and negative terminals are called electrodes.
5. The carbon rod is surrounded by a mixture of carbon powder and a chemical called ammonium chloride. This mixture acts as an electrolyte.
6. The cell is sealed from the top.

Activity – 2

Question 2.
How do you make an own cell?
(OR)
Can you make a cell? If you can write the procedure.
(OR)
Write the procedure of making a cell using lemon.
Answer:
Material required: Zinc plate, Copper Plate, A small bulb or LED, Connecting wires and Lemon or Orange, crocodile clips-4.

Procedure:
Take a Lemon and insert a Zinc plate and a Copper plate into it as shown in the fig. These plates act as electrodes and the juice inside the fruit acts as electrolyte. Connect two terminals of the bulb to zinc and copper plates using connecting wires.

We observe that the bulb will glow as electricity was produced using chemical energy present in the lemon.

Activity – 3

Question 3.
Write an activity two observe the brightness of bulb in the following situations.
1) One cell and one bulb.
2) Two cells in series and one bulb.
3) Two cells in parallel and one bulb.
(OR)
How is the brightness of a bulb when it connected to a circuit with cells which are connected i) in series and ii) in parallel? Explain with an activity.
Answer:
Situation-1
Material required :
Dry cell -1, Small bulb-1 (torch light bulb or LED), Switch and Connecting wire.

Procedure:
Take a dry cell, small bulb or LED and a switch. Connect them in a simple circuit using copper wire as shown in given fig. Switch ON and observe the brightness of light. ,

Situation-2 (Cells connected in series) :
Material required :
Dry cells -2, Small bulb-1 (torch light bulb or LED), Switch and Copper wire.

Procedure:
Take two dry cells, small bulb and a switch. Connect them using a copper wire as shown in the fig. Switch ON and observe the brightness of light. Remove one cell and observe the condition of bulb.

Situation-3 (Cells connected in parallel) :

Material required :
Dry cells -2, Small bulb -1 (torch light bulb or LED), Switch and Copper wire.

Procedure:
Take two electric cells small bulb or LED and switch. Connect them using copper wire as shown in fig.

Switch ON and observe the brightness of bulb.Remove one cell and observe the condition of bulb.Record your observations in the above three situations in the given table.

From the table, if a number of cells are connected in series the brightness of the bulb isenhanced. If one of the cells is removed, the circuit becomes open and the bulb will not glow.If a number of cells are connected in parallel the brightness of the bulb remains same. Evenlf one of the cells is removed, the circuit remains same and the bulb will glow as usual.

Activity – 4

Question 4.
Write an activity to show the brightness of the bulbs when two bulbs are connected in series and in parallel.
Answer:
Situation-1
Materials required:
Dry cell -1, Small bulb-1 (torch light bulb or LED), Switch and Connecting wire.

Procedure :
Take a dry cell, small bulb or LED and switch.Connect them in a simple circuit using copper wireas shown fig.. Switch ON and observe the brightness of light.

Situation-2 (Bulbs connected in series):
Materials required:
Electric cell -1, Small bulbs -2 (torch light bulb or LED), Switch and Copper wire.

Procedure :
Take two small bulbs or LED’s, cell and switch.

Connect them using copper wire as shown in fig. Switch ON and observe the brightness of the bulbs. Remove one bulb and observe the condition of another bulb.

Situation-3 (Bulbs connected in Parallel):
Materials required:
Electric cell -1, small bulb -2 (torch light), Switch, Copper wire.

Procedure:
Take two small bulbs, a cell and a switch.Connect them using copper wire as shown in fig. Switch ON and observe the brightness of the bulbs.

Remove one bulb and observe the condition of another bulb.

From the table,if a number of bulbs are connected in series the brightness of the bulb is reduced. If one of the bulbs is removed or broken, the circuit becomes open and the second bulb will not glow. If the number of bulbs are connected in parallel the brightness of the bulb remains same. Even if one of the bulb Is removed or broken, the circuit remains same and the bulb will glow as usual, but the battery drains faster.

Activity – 5

Question 5.
Write an activity to know about beating effect of electric current.
(OR)
What happens if Garment is passed through a Nichrome wire? Explain with an activity.
(OR)
How do von show the heating effect of electricity through an activity?
Answer:
Materials required:
Electric cell, switch. Iron nails-2, wooden board, connecting wires, 10 cm of Nichrome wire.

Procedure :
Construct a circuit using electric cell, switch, connecting wires and iron nails in series connection. Insert the iron nails in the wooden board. Keep the switch in OFF position. Take Nichrome wire and tie it between the iron nails as shown in fig.

Observations :
Now switch ON the circuit for one minute, and switch it OFF. Now, touch the Nichrome wire, (don’t hold Nichrome wire for a long time.) You will observe that the Nichrome wire gets heated up when electricity passed through it. The production of heat due to the flow7 of electricity through a wire is called Heating Effect of Electricity.

Activity – 6

Question 6.
Write an activity to know about magnetic effect of electric current.
(OR)
How do you make an electromagnet?
(OR)
How do you prepare an electromagnet?
Answer:
Material required:
Battery, Switch Iron nail (nearly 8 cm). Insulated copper wire (50 cm) and small pins.

Procedure:
Take an iron nail and wound the insulated copper wire tightly around the nail. This iron aaS works as a coil. The two ends of the coiled copper wire are connected to a battery and a switch in series connection as shown in fig. (Switch roast be in OFF position. Place some pins near the iron nail and switch ON the circuit.

We observe that, when we switched, on the circuit, all pins ding to the end of the iron nail. This indicates coiled copper wire around nail acts as magnet when electricity passes through it. It means the coiled copper wire around the nail acts as an electromagnet.

When we switched off the circuit, immediately all the pins fall from the iron naS. This indicates that coiled copper wire does not act as a magnet when no electricity7 passes through the circuit

Magnetic effects produced in a coil due to the passing of electricity in the coil is called magnetic effects of electricity.

SCERT AP 7th Class Science Study Material Pdf 2nd Lesson Nature of Substances Textbook Questions and Answers.

AP State Syllabus 7th Class Science 2nd Lesson Questions and Answers Nature of Substances

7th Class Science 2nd Lesson Nature of Substances Textbook Questions and Answers

Improve Your Learning

I. Fill in the blanks.

1. Taste of an acid is ______ .
2. The pH of a substance is 0. It indicates that the substance is ______ in nature.
3. Blue litmus paper turns ______ colour in tamarind solution.
4. The nature of an antacid is ______
5. Acid + base → ______ + ______
Answer:
1. sour
2. acidic
3. red
4. basic
5. salt + water

II. Choose the correct answer.

1. Colour of Turmeric solution in acids
a) Blue
b) Red
c) Purple
d) No change
Answer:
d) No change

2. Example to an acid.
a) Vinegar
b) Baking soda
c) Caustic soda
d) None
Answer:
a) Vinegar

3. Main component of soap is
a) An Acid
b) A base
c) a & b
d) None
Answer:
b) A base

4. If you add baking soda to lemon juice ______ gas will release.
a) Hydrogen
b) Oxygen
c) Carbon Dioxide
d) Sulphur Dioxide

5. To treat acidic nature of the soil, farmers add ______ to his agricultural field.
a) lemon juice
b) calcium oxide
c) sodium chloride
d) sulphur dioxide
Answer:
b) calcium oxide

III. Matching

A) Battery	1. Preservation
B) Soap	2. Calcium carbonate
C) Acetic acid	3. Sulphuric acid
D) Hibiscus	4. Synthetic indicator
E) Egg shell	5. Sodium hydroxide
	6. Natural indicator

Answer:

A) Battery	3. Sulphuric acid
B) Soap	5. Sodium hydroxide
C) Acetic acid	1. Preservation
D) Hibiscus	6. Natural indicator
E) Egg shell	2. Calcium carbonate

IV. Answer the following questions.

Question 1.
Write differences between acids and bases.
Answer:

Acids	Bases
1) Acids are sour to taste	1) Bases are bitter to taste
2) They are not slippery to touch.	2) They are slippery to touch
3) Blue litmus turns red in acids.	3) Red litmus turns blue in bases.
4) Methyl orange turns red in acids.	4) Methyl orange turns yellow in bases.
5) Phenolphthalein does not change its colour in acids.	5) Phenolphthalein turns pink in bases.
6) Acids turns into pink on adding hibiscus indicator.	6) Bases turns green on adding hibiscus indicator
7) pH of acids is less than 7.	7) pH of bases is more than 7.
8) Acids react with metals and release hydrogen gas.	8) Bases like sodium hydroxide react with metals and releases hydrogen gas along with salt.

Question 2.
Give examples to different types of acid and base indicators.
Answer:
Substances which are used to test acids or bases are called acid base indicators. There are many types of indicators, some of them are

1. Natural indicators
2. Synthetic indicators
3. Olfactory indicators
4. Universal indicators.

1) Natural indicators:
Indicators obtained from natural sources are called as Natural indicators. Ex: litmus, turmeric, hibiscus, red cabbage etc.

2) Synthetic indicators:
An indicator prepared from artificial sources is known as Syn-thetic indicator. We use many synthetic indicators like methyl orange, phenolphtha-lein, in our laboratory.

3) Olfactory indicators:
Substances which change their smell when mixed with acid or base are known as olfactory indicators. Ex: onion, vanilla and clove oil.

4) Universal indicators:
It is a mixture of different indicators. It shows different colours in different solutions, “universal indicator” contains thymol blue, methyl red, bromothymol blue and phenolphthalein.

Question 3.
One substance is slippery to touch and bitter in taste, another substance is sour in taste. If you add both, which substances will form?
Answer:

1. Substance that is slippery to touch and bitter in taste is Base.
2. Substance that is sour in taste is Acid.
3. When acids react with base neutralisation reaction takes place.
4. Salt and water will form in neutralisation reaction.
   Acid + Base → Salt + Water

Question 4.
Guess, How do you test acetic acid, if there is no availability of indicators?
Answer:

1. Acetic acid is a colour less liquid with pungent smell and sour taste.
2. It is used in preservation of pickles and other food substances as it is sour.
3. So, It can be identify by testing its smell and taste.

Question 5.
Anitha’s mother was filled mango pickle in a ceramic jar and stored, so many doubts were arisen her mind. What would be those doubts?
Answer:

1. Why do pickles store only in ceramic jars?
2. What materials are used in making ceramic jars?
3. What will happen if pickles are stored in metal containers?
4. Sometimes pickles spoil quickly. Why?
5. Do all pickles contain oil?
6. Why is it not suggestable to use aluminium spoons for pickles?

Question 6.
To conduct a neutralization reaction, what materials are required?
Answer:
Materials required to conduct a neutralization reaction are dilute hydrochloric acid (any acid), Sodium hydroxide solution (any base), Phenolphthalein indicator, Conical flask, Dropper.

Question 7.
Draw a neat diagram of arrangement of apparatus to conduct an activity that acid reacts with metal and liberates hydrogen gas.
Answer:

Question 8.
How do you appreciate the role of bases in helping of the persons suffering from acidity problems?
Answer:

1. Our stomach produces gastric juice with hydrochloric acid.
2. It helps us in digestion of food.
3. But sometimes secretion of excess acid causes acidity or indigestion.
4. It leaves a burning sensation and pain in the stomach.
5. Antacids help us to get relief from acidity.
6. Antacids contain bases, eg: aluminum hydroxide, milk of magnesia.
7. The bases in the antacids neutralize gastric juice and give us relief.
8. Thus bases do a great help to the persons suffering from acidity problems.

Question 9.
What measures do you follow to prevent acid rains?
Answer:
Air pollution is a major cause of acid rains. So acid rains can be prevented by controlling the air pollution. To control air pollution

1. Reduce the usage of personal vehicles.
2. Reduce the usage of fossil fuels.
3. Encourage the usage of alternative sources of energy.
4. Use electric vehicles.
5. Use solar energy.
6. Minimize use of fire and fire products.
7. Treat and purify the industrial emissions before letting in to air.
8. Plantation and reforestation should be done as much as possible.

7th Class Science 2nd Lesson Nature of Substances InText Questions and Answers

7th Class Science Textbook Page No. 20

Question 1.
Name any other substance which tastes like tamarind?
Answer:
Lemon juice is another substance which has sour taste like tamarind.

Question 2.
Why are tamarind and lemon juice sour in taste?
Answer:
Substances like tamarind and lemon contain some substances which give sour taste. These type of substances with sour taste are known as acids.

7th Class Science Textbook Page No. 21

Question 3.
What do you observe when an acid is poured on the bathroom floor?
Answer:
Generally, hydrochloric acid is used for bathroom cleaning. It liberates thick fumes and pungent smell when poured on the floor.

Question 4.
Have you seen batteries being used in vehicles? Which chemical is used in batteries?
Answer:
Sulphuric acid is used in batteries.

Question 5.
Have you ever drunk a soda or a cool drink?
Answer:
Yes. It contain carbonic acids.

Question 6.
Which substances do you use to wash your hands and clean your teeth?
Answer:
We use soap to wash our hands and for bathing. We use tooth paste to clean our teeth.

Question 7.
What are the chemicals present in soap and tooth paste?
Answer:
Soap and tooth paste contain bases.

7th Class Science Textbook Page No. 22

Question 8.
See the main components on the tooth paste tube. What chemicals names do you find?
Answer:
Calcium carbonate, aluminium hydroxide and sodium bicarbonate etc.

Question 9.
Is there any substance other than an acid and a base? Discuss with your Mends.
Answer:
The substance which is neither an acid nor a base is known as neutral substance. Pure water is a neutral substance.

Question 10.
List out some acids, bases and neutral substances available in your house.
Answer:
Acids:
Vinegar, lemon juice, tomato juice, bathroom cleaner (hydrochloric acid), cool drinks, curd, etc.

Bases :
Bath soap, cloth soap, baking soda, tooth paste, dish wash liquid etc.

Neutral: Water

7th Class Science Textbook Page No. 23

Question 11.
Is it possible to test all the acids and bases simply by tasting or touching them?
Answer:

1. Not possible.
2. Some acids like hydrochloric acid, sulphuric acid etc. are very harmful and strong acids. We cannot test them by touch or taste.

Question 12.
In such cases, how can we test them whether they are acids or bases?
Answer:
By using acid base indicators.

Question 13.
What are the different types of indicators?
Answer:
There are many types of indicators, some of them are

1. Natural indicators
2. Synthetic indicators
3. Olfactory indicators
4. Universal indicators.

7th Class Science Textbook Page No. 24

Question 14.
Can we use any flower as an indicator?
Answer:
We can use hibiscus flowers as an indicator. We can also use Indigofera tinctoria (Neeli chettu) flowers as indicator.

7th Class Science Textbook Page No. 26

Question 15.
Why it is so? What makes the hydrochloric acid dangerous than vinegar?
Answer:

1. Hydrochloric is an strong acid whereas vinegar is a weak acid.
2. pH of hydrochloric is very less than that of vinegar.

Question 16.
How can we measure the strength of an acid or a base?
Answer:
Strength of acid or base solutions is measured in pH scale.

7th Class Science Textbook Page No. 27

Question 17.
What happens when a metal piece is dropped in an acid?
Answer:
If you drop a metal piece in an acid it reacts with acid and releases hydrogen gas.

7th Class Science Textbook Page No. 28

Question 18.
Pickles are not stored in aluminium or steel or copper vessels. Why?
Answer:

1. Pickles contain acids.
2. These acids react with metal containers and releases toxic substances.
3. So, we should not store them in metal containers.
4. Generally, they are stored in ceramic or glass containers which are not react.

Question 19.
What will happen when metals are placed in bases?
Answer:
Bases like sodium hydroxide react with metals and release hydrogen gas.

7th Class Science Textbook Page No. 29

Question 20.
What will happen if we mix an acid and a base?
Answer:
If we add an acid to a base, they neutralize each other.

7th Class Science Textbook Page No. 30

Question 21.
How is acidity caused? What is the remedy for it?
Answer:

1. Excess secretion of gastric juice (hydrochloric acrd) in the stomach causes acidity problems.
2. Antacids help the patients to get relief from acidity.

Question 22.
What are antacids?
Answer:
Antacids are bases. They neutralize the gastric juice in the stomach.

7th Class Science Textbook Page No. 31

Question 23.
How can you help the farmers in finding out whether their agriculture fields are acidic or basic?
Answer:
We can help the farmers by testing the soil in their fields.

Activities and Projects

1. Prepare different greeting cards by using indicators.
Answer:

I had prepared a greeting card using turmeric indicator.

I took a white card board and cut it in the shape of a greeting card.

Applied turmeric paste on it and allowed to dry.

I draw designs and wrote wishes on it with soap water using a point brush.

It turns in to reddish brown.

Thus, I prepared greeting card using indicator.

Question 2.
Prepare beetroot indicator and test some acids and bases. Write a report.
Answer:
I have crushed beetroot and collected its juice.

This juice is filtered and used as an acid-base indicator.

When acids are added to this indicator there is no change in colour.

But when bases are added to this, it changed its colour from dark red to yellow. With this I concluded that the beetroot indicator is used to test the bases.

Test with beetroot indicator

Solution	Colour changes into yellow
1. Lemon juice	✗
2. Glass cleaner	✓
3. Water	✗
4. Sodium hydroxide	✓
5. Potassium hydroxide	✓
6. Hydrochloric acid	✗

Question 3.
Visit various agricultural fields and collect soils samples. Do the soil test. Make a report.
Answer:
I have visit nearest agricultural fields and collected soil from the fields. I took 10 g of soil from each sample in a beaker and added 500 ml of water to it. I stirred it well and filtered the solution. Then tested the filtered solution with a pH paper and tabulated the results. I gave suggestions to the farmers to neutralize their soils basing on the results.

Activities

Activity – 1

Question 1.
Taste some substances in our house and identify their nature through taste from your previous experiences. Fill the findings in the table.

Answer:

Substance	Taste	Acid/Not An Acid
1. Tomato juice	sour	acid
2. Sugar	sweet	not an acid
3. Curd	sour	acid
4. Raw mango	sour	acid
5. Table salt	salt	not an acid
6. Amla (usiri)	sour	acid
7. Orange juice	sour	acid

→ Which substances have sour taste in the above table? Why?
Answer:
Tomato juice, curd, raw mango, amla and orange juice have sour taste, because they contain acids. . .

Activity – 2

Question 2.
Take a soap into your palm and add some water. Now rub with another palm.
→ How do you feel while rubbing?
Answer:
You can feel the slippery nature of the soap.

Repeat this activity with tooth paste now. Observe your feeling.

Tooth paste is also slippery in nature.

These substances contain slippery chemicals they are called Bases. Bases are slip¬pery in nature and also bitter to taste.

Activity – 3

Question 3.
Take a table spoon of turmeric powder in a plate. Add little water and make it into a paste. Take a white paper and apply the paste over it on both sides and let it dry. After drying, cut the paper into strips. Now turmeric paper strips are ready for use as indicator.
→ What is the colour of these strips?
Answer:
They are yellow in colour.
Testing with turmeric indicator

1. Take soap solution in a plate. Dip one turmeric paper strip in the soap solution.
2. Take it out and observe the colour of the strip.
3. Repeat the activity with lime water and lemon juice.

→ Do you observe any change in colour of tumeric strips?
Note your observations in the table.
Answer:

Substance	Observed colour change
Soap solution	Reddish brown
Lime solution	Reddish brown
Lemon juice	No change

The colour of turmeric strip will change into reddish brown in soap water and lime water, but its colour will not change in lemon juice.

Test with hibiscus indicator :
Take lemon juice, soda water, lime water, glucose solution, sugar solution, soap water etc.into test tubes. Add sufficient amount of hibiscus indicator in each test tube.Observe the change in the colour of the substance and record in the table.

Name of the Substance	Observed colour change
1. Lemon juice	Changed to pink
2. Soda water	Changed to pink
3. Lime water	Changed to green            .
4. Glucose solution	No Change
5. Sugar solution	No Change
6. Soap water	Changed to green

7th Class Science Textbook Page No. 24

Question 4.
How do you prove that hibiscus could be used as an acid base indicator?
(OR)
How do you prepare a hibiscus indicator?
Answer:

1. Take some hibiscus (china rose or mandara) petals.
2. Take warm water into a beaker and place the petals in the beaker.
3. Keep it until the water has completely turned into violet colour.
4. Filter the solution with a strainer.
5. Now hibiscus indicator is ready to test.

Test with indicator:

1. Take lemon juice, soda water, lime water, glucose solution, sugar solution, soap water etc. into test tubes.
2. Add sufficient amount of hibiscus indicator in each test tube.
3. Observe the change in the colour of the substance and record in the table.

Name of the substances	Observed colour change
1. Lemon juice	pink
2. Soda water	pink
3. Lime water	green
4. Glucose solution	no change
5. Sugar solution	no change
6. Soap water	green

Conclusion :
In acids and bases the hibiscus indicator changes its colour. Hence, it can used as an acid base indicator.

Lab Activity – 1

Question 5.
Test the given solution with different indicators and prepare a report.
(OR)
How do you test different indicators change their colours in different solutions?
Answer:
1) Take the solutions a) Dilute hydrochloric acid b) Sodium hydroxide c) Acetic acid d) Salt solution e) Sugar solution f) Soap solution in test tubes.

2) Test them with a) Red litmus b) Blue litmus c) Methyl orange d) Phenolphthalein indicators.
Table

3) Blue litmus turns red in acids.
4) Red litmus turns blue in bases.
5) Methyl orange turns red in acids and yellow in bases.
6) Phenolphthalein turns pink in bases, but does not change its colour in acids.
7) In neutral substances all the above indicators do not change their colour.

Activity – 4

Question 6.
How do you find the strength and nature of the following substances?
1) Dilute hydrochloric acid
2) Vinegar
3) Water
4) Sodium hydroxide
5) Ammonium hydroxide.
Answer:
Take dilute hydrochloric acid, vinegar, water, sodium hydroxide and ammonium hydroxide in test tubes.;Now take universal indicator and add 2 drops in each test tube. You can observe that the solutions in the test tubes change into different colours. Now compare these colours with pH colour chart which was given on the indicator bottle.
Try to find pH values or the strengths Of acids and bases based on the colours they show and write them in the table.
Table

Lab Activity – 2

Question 7.
How do you prove that the acid reacts with metals and produces hydrogen gas?
Answer:
Aim: Acid Reacts with metals and produces hydrogen gas.

Materials required:
Conical flask, hydrochloric acid, zinc pieces, incense stick, match box.

Procedure:
Take 5g of zinc metal pieces in a conical flask. Pour 20 ml of dilute hydrochloric acid into it. Now, observe what happens. The zinc pieces reacted with the hydrochloric acid and releases a gas.

How can we identify this gas?
Test for hydrogen gas :
Now, introduce a incense stick into mouth of the conical flask. The flame of incense stick will put off with a pop sound. This is a test for hydrogen gas. Hydrochloric acid reacts with zinc metal and forms zinc chloride, releases hydrogen gas. This reaction can be written as a word equation,
Zinc+hydrochloric acid → zinc chloride+hydrogen

Conclusion:
Hence, we can conclude that acids react with metals and release hydrogen gas.

Activity – 5

Question 8.
How do you prove that bases react with metal and releases hydrogen gas ?
Answer:
Aim: Base reacts with metal and produces hydrogen gas.

Material required :
Conical flask, sodium hydroxide solution, zinc pieces, incense stick.

Procedure:

1. Take 5gr of zinc metal pieces in a conical flask,
2. Pour 20 ml of sodium hydroxide solution in it.
3. Heat the conical flask.

Observation :
The zinc pieces reacts with base and releases gas.

Test for hydrogen gas :

1. Now, introduce a incense stick into the mouth of the conical flask.
2. The flame of incense stick will put off with a pop sound.
3. This is a test for hydrogen gas.

Conclusion :
Bases react with metals and produce hydrogen gas.
Note : All bases do not react with metals.

Activity – 6

Question 9.
How do you prove that the carbon dioxide gas releases when an egg shell reacts with an acid?
(OR)
What happens when egg shells are dipped in an acid? How do you prove it?
Answer:
Take some crushed egg shells in a test tube and pour dilute Hydrochloric acid until the egg shells completely sink. Egg shell is made of calcium carbonate. Bring a burning match stick near the mouth of test tube.

The gas that put off the burning match stick is carbon dioxide. It was released by the action of acid with calcium carbonate.

Activity – 7

Question 10.
How do you perform a neutralization reaction in your lab?
Answer:

1. Take sodium hydroxide solution in a conical flask and observe its colour. Now add 2-3 drops of phenolphthalein indicator to it.
2. Now observe the colour. It is pink in colour.
3. Using a dropper add dilute hydrochloric acid drop by drop to this solution and stir gently.
4. Continue adding of the acid, till the pink colour disappears.
5. The solution now is no more basic as it was neutralized by acid.
6. We know that the colour of phenolphthalein indicator is pink in bases and colourless in acids and neutral substance.
   
7. The substances are salt and water because acids react with bases to form salts and water,
8. Neutralization is a chemical reaction where acid and base reacts with each other to forms salt and water.
9. Word equation of the above reaction is
   Hydrochloric acid + sodium hydroxide → Sodium chloride + water
10. Now add one or more drops of hydrochloric acid to the solution. The pink colour disappears, as it has again become acidic.
11. We can conclude that acids react with bases to produce salt and water.

Activity – 8

Question 11.
How do you test soil of agricultural field?
Answer:
Visit nearest agricultural fields and collect soil from the fields.

Take 10 g of soil in a beaker. Add 500 ml of water to it and stir well. Filter the solution. Now test the filtered solution with universal indicator or a pH paper and check your results.

Field	pH	Nature of the soil
Field -1	6	Slightly acidic
Field -2	7	Neutral
Field -3	8	Slightly basic

SCERT AP 7th Class Science Study Material Pdf 8th Lesson Wonders of Light Textbook Questions and Answers.

AP State Syllabus 7th Class Science 8th Lesson Questions and Answers Wonders of Light

7th Class Science 8th Lesson Wonders of Light Textbook Questions and Answers

Improve Your Learning

I. Fill in the blanks.

1. Image formed by convex mirror is erect, small and _______
2. Infinite number of images are formed between two mirrors if they are kept at an angle of _______
3. Dentists use _______ mirror to see inner parts of teeth.
4. Image that cannot be obtained on screen is______
Answer:
1. virtual
2. 0°
3. concave
4. virtual

II. Choose the correct answer.

1. In periscope, the angle between two plane mirrors is
a) 0°
b) 30°
c) 45°
d) 60°
Answer:
a) 0°

2. If two plane mirrors are kept at an angle of 180° between them. Then the number of
a) 1
b) 2
c) 3
d) 4
Answer:
a) 1

3. Which of the following is not the property of image formed by a plane mirror?
a) Same size
b) Real
c) Lateral inversion
d) Erect
Answer:
b) Real

4. If a light ray falls on plane mirror along the direction of normal, then the angle of reflection will be
a) 90°
b) 45°
c) 0°
d) 180°
Answer:
a) 90°

5. Which form clear image among the following?
a) Paper
b) Cloth
c) Card board
d) Plane mirror
Answer:
d) Plane mirror

III. Match the following.

A) Reflections from Ice pieces	1. Regular reflection
B) Reflections from still water	2. Irregular reflection
C) Reflectors in head lights	3. Blue light
D) Rear view mirrors	4. Concave mirror
E) Light which causes damage to retina	5. Yellow light
	6. Convex mirror

Answer:

A) Reflections from Ice pieces	2. Irregular reflection
B) Reflections from still water	1. Regular reflection
C) Reflectors in head lights	4. Concave mirror
D) Rear view mirrors	6. Convex mirror
E) Light which causes damage to retina	3. Blue light

IV. Answer the following questions.

Question 1.
What is reflection of light? Explain with an example.
Answer:

1. The process of bouncing back of light rays into the same medium after falling on a smooth or rough surface from the light source is called “reflection of light”.
   Example:
2. Take a plane mirror and stand in front of a building in open space during the day. Let the sunlight falls on the mirror. Now rotate the mirror in such a way that a spot of light falls on the wall of building.
3. In the above activity, light rays fall on the mirror bounced back. This process of bouncing back of light rays in the same medium after hitting the surface of an object is called reflection.

Question 2.
Write the laws of reflection of light.
Answer:
There are two laws of reflection :

1. First law of reflection : Angle of incidence is equal to angle of reflection.
2. Second law of reflection : The incident ray, reflected ray and normal to the surface are present in the same plane. Incident and reflected rays are on either side of normal.

Question 3.
Why should we keep the mirror strips in the Periscope parallel to each other? What happens if they are not parallel?
Answer:

1. We should keep the mirror strips in the Periscope parallel to each other. The image of an object formed on the first mirror reflects exactly on the second mirror and then we can see the image. It is possible when the mirror strips in the Periscope parallel to each other.
2. If they are not parallel, the image of an object formed on the first mirror does not reflects on the second mirror and we cannot see the image through the second mirror.

Question 4.
What precautions do you take while getting the image of burning candle using a mirror?
Answer:

1. Keep the candle as its flame is in the line of the mirror.
2. Keep the mirror as its plane opposite to the screen.
3. Do the experiment in a dark room.
4. Take care while handling the candle with flame.

Question 5.
Write the properties of images formed by concave mirror.
Answer:
The properties of images formed by concave mirror.

1. It can form both real and virtual images.
2. It produces erect and inverted images
3. It also produces small same size and bigger images depending on the position of object in front of it.

Question 6.
Draw the diagram show regular reflection and diffused reflection of light.
Answer:

Question 7.
Where do you find multiple images formed by plane mirrors in your day-to-day life?
Answer:

1. In sweet shops mirrors are arranged in such a way that multiple images of sweets can appear.
2. In saloon and beauty parlours mirrors are arranged in such a way that the customers can view his images in all directions.
3. In bathrooms and dressing rooms also, we can observe multiple images.
4. In Kaleidoscope we can observe multiple images.

Question 8.
Where do you find irregular reflections in your daily life?
Answer:
We can find irregular reflections on unpolished marbles floors, scratched steel vessels, broken mobile screens, disturbed water surfaces, and on the rough surfaces of plastic sheets, metal sheets, etc.

Question 9.
Write the applications of spherical mirrors in daily life.
Answer:
Applications of concave mirrors:

1. Concave mirrors are used by ENT doctors as Head Mirrors.
2. Dentists also use concave mirrors to get a bigger image of the teeth.
3. Eye specialist using a special instrument called Ophthalmoscope. It is fitted with a concave mirror having a small hole near its center.
4. Concave mirrors are used to reflectors in a torch light or the headlights of vehicles.
5. These are used in microscopes.

Applications of convex mirrors:

1. Convex mirrors are used as Rear-view mirrors in vehicles.
2. Convex mirrors are also used at the junctions of roads.
3. Convex mirrors are used at ATM machines.
4. Convex mirrors are used for security purpose at factories, offices, etc.

7th Class Science 8th Lesson Wonders of Light InText Questions and Answers

7th Class Science Textbook Page No. 16

Question 1.
What do you observe in the picture? Mention the different objects in the scenery.

Answer:
Trees, river, hills, rainbow, steps, boat, a boy, a girl, butterfly, water, plants, wooden bridge.

Question 2.
Can we see all these objects during night time?
Answer:
No, we cannot see all these objects during night time.

7th Class Science Textbook Page No. 17

Question 3.
Where does the light come from?
Answer:
Light comes from different objects called sources of light.
Ex : Sun, candle, tubelight.

Question 4.
Name some sources of light around you.
Answer:
Sun, candle, tubelight, bulb, torch light, match box etc .

Question 5.
Do these sources release light on their own?
Answer:
Sources like sun, stars emit light on their own.
Sources like bulb, torch light, candle do not emit light on their own.

Question 6.
Can you give some other examples for natural sources of light?
Answer:
The moon, stars and the sun.

Question 7.
Do you know how this light travel from the source?
Answer:
Actually, light is not a single ray, but a bundle of rays- This bundle of light rays are called beam of light rays. .

Question 8.
What do we call the path of light?
Answer:
The direction or path along which light travels is called a ray of light.

7th Class Science Textbook Page No. 18

Question 9.
How are we able to see the objects?
Answer:
The light fall on the objects and reflects and reach to our eye.

Question 10.
Is only light enough to see the objects around us?
Answer:
Yes, light is enough, but reflected light should reach our eye.

7th Class Science Textbook Page No. 19

Question 11.
In the activity-2, is there any reflection from the reflected light?
Answer:
Yes, there is reflection from the reflected light.

7th Class Science Textbook Page No. 23

Question 12.
We are able to see our image in the mirror. Can we catch our image bn screen?
Answer:
No. We cannot catch our image on screep.

7th Class Science Textbook Page No. 24

Question 13.
Are the images formed by plane mirrors real or virtual?
Answer:
Plane mirror forms virtual image.

Question 14.
Have you observed the arrangement of plane mirrors in a sweet shop? How many images did you find?
Answer:
Yes, I have observed the arrangement of plane mirrors in a sweet shop. So many images are formed.

7th Class Science Textbook Page No. 25

Question 15.
How many images are formed when the angle between two mirrors is zero?
Answer:
Number of images (n) = (360°/θ) – 1= ∞ , from the formula, we can find infinite number of images are formed. –

7th Class Science Textbook Page No. 26

Question 16.
Have you ever seen your image in rearview mirror of your father’s, motor cycle?
Answer:
Yes.

Question 17.
Is it same as the image seen in the mirror of your dressing table?
Answer:
No

Question 18.
What difference did you observe?
Answer:
Image is small in and closure.

Question 19.
What may be the reason for the difference?
Answer:
May be shape of the surface of the mirror.

Question 20.
Touch the surface of the rearview mirror. Is it same as plane mirror?
Answer:
No. It is not same as plane mirror. It is in curved in shape.

7th Class Science Textbook Page No. 28

Question 21.
Do you know the use of spherical mirrors in your daily life?
Answer:
Concave mirrors are used by dentists, ophthalmologists, ENT doctors and also in head lights of vehicles. Convex mirrors are used as rear view mirrors in vehicles and safety mirrors at curved roads.

7th Class Science Textbook Page No. 29

Question 22.
Have you ever observed the surface of reflection in a torch light or the headlights of vehicles?
Answer:
Yes, they are spherical in shape.

7th Class Science Textbook Page No. 30

Question 23.
Can you recognize the mirrors used beside the drivers in vehicles?
Answer:
These are convex mirrors.

Question 24.
Can you now recognize the characteristics of image from rear view mirror?
Answer:
Erect, virtual and smaller images are formed.

Question 25.
Do all the objects reflect the light rays falling on it?
Answer:
No.

Question 26.
Do you know why did paper burnt with a magnifying glass?
Answer:
The paper burned as the magnifying glass concentrated the sun’s rays at one place on the paper.

Question 27.
Doesthe magnifying glass reflect the light falling on it?
Answer:
No.

Think & Respond

7th Class Science Textbook Page No. 23

Question 1.
Deepak saw a vehicle on the road. He was surprised to see that the word on it. What was that word? Why was it written in a strange manner?
Answer:

1. The word is AMBULANCE.
2. AMBULANCES are emergency vehicles.
   It is important to give way to ambulances.

The drivers can see the rear coming vehicles through the rear view mirror of the vehicles. Objects and letters appear in reverse means in left right inversion in mirrors. So letters in the wf>rd AMBULANCE also appear in reverse and cannot understand the word to the drivers.

If the word is written in reverse (as in mirror image) on the ambulance, it appears normally and readably. Drivers can read the word AMBULANCE and give a way to ambulance immediately.

Activities and Projects

Question 1.
Large sized concave mirrors are used to focus sun rays in solar cookers and solar heaters.Make a solar cooker of your own by using this principle and exhibit in your school science fair.
Answer:

Making of solar cooker :

1. A concave mirror focuses parallel sun rays at the focal point of the mirror.
2. So with a small concave mirror .we can heat up and burn paper.
3. In the same way make a big concave mirror to heat up a vessel.
4. Make a wooden/ iron frame in the shape of TV dish.
5. Cut acrylic mirror sheets into 8 or 12 pieces in the shape of isosceles triangles with a height equal to the radius of dish antenna.
6. The bases of 8 or 12 triangles together make the circumference of the dish.
7. Stick the triangle mirrors to the dish.
8. Our solar heater/cooker is ready.
9. Arrange it so that concave part faces sun.
10. Find its focal point and place a vessel at that point.
11. It will get heated. We can even cook rice in that vessel.

Question 2.
Prepare a report by collecting data on the uses of spherical mirrors.
Answer:
Spherical mirrors are two types : They are 1) concave mirror 2) convex mirror.

1) Concave mirror :
Concave mirrors have a smooth curved surface inwards. Light rays are converged at one point by a Concave mirror. Real and virtual images can form the concave mirror.

The applications of concave mirror in our daily life :
Dentists :
Concave mirrors are used by dentists in the examination of teeth.

ENT doctors:
These are used by ENT doctors to examine the body parts.

Shaving mirrors :
During shaving, the concave mirror forms an enlarged and erect image of the face when the mirror is held closer to the face.

Optical instruments:
Ophthalmoscope concave mirrors are used in optical instruments such as Ophthalmoscope.

Astronomical telescopes:
These are used in telescopes and other devices. Headlights : Concave mirrors are widely used in headlights of automobiles and motor vehicles, torchlights, railway engines, etc. as reflectors. The light source is placed at the focus of the mirror, so after reflecting the light rays travel over a huge distance as parallel light beams of high intensity.

Solar cookers :
Concave mirrors are also used in solar cookers. Concave mirrors are also used in satellite dishes, electronic microscope, visual bomb detectors, etc.

2) Convex mirror .
Convex mirrors have a smooth curved surface outwards. Light rays are diverged at one point by a Convex mirror. Only virtual images can form the convex mirror.

The applications of convex mirror in our daily life.

Rear-view mirrors:
These are convex mirrors. These mirrors form images of objects spread over a large area. So, these help the driver to see the traffic behind them. Hence these are used as Rear-view mirrors.

Road safety:
Convey mirrors kept at the corners of curved roads to avoid accidents. Convex mirrors form images of vehicles on both sides of curved road. These mirrors are also used at the mnctions of roads.

Question 3.
Make a list of objects in your school and home, that works like a mirror. Make a report why they work like that.
Answer:

1. Plane mirror : It has plane surface. So it reflects the light.
2. Water surface : It has plane surface, when it was stable. So it reflects the light.
3. Tiles of floor : It has plane surface. So it reflects the light.
4. Almara : It was painted and has a smooth plane. So it reflects the light.
5. Steel plate : It has a smooth plane. So it reflects the light.
6. Concave and convex mirrors : It has plane surface. So it reflects the light.
7. Computer screen : It has plane surface. So it reflects the light.
8. Steel spoon : It has plane surface. So it reflects the light.

Question 4.
Take an empty tooth paste box and two mirror strips of required size and make a periscope.
Answer:
Collect the following materials to make your own periscope.

1. Empty tooth paste box, two mirror strips, scale, pencil, blade, gum.
2. Take an empty tooth paste box.
3. Close the ends and draw two squares at both the ends by using scale and pencil.
4. Draw diagonals to the square boxes, such that the two diagonals facing each other.
5. Make two slits with the help of blade along the diagonals.
6. Make sure that the size of mirror should be equal to the length of slits.
7. Fix the mirror strips in the slits in such a way that reflecting surfaces of mirror strips face pach other.
8. Fix the mirror strips firmly to the box by using gum.
9. Cut out two windows on the narrow sides such that the windows should open directly on the reflecting surfaces of the mirror strips. Now the Periscope is ready.

Activities

Activity – 1

Question 1.
Write an activity to show the following type of light rays,
i) Parallel beam of light rays
ii) Converging beam of light rays
iii) Diverging beam of light rays
Answer:
i) Parallel beam of light rays:
Light rays which travel parallel to each other are called Parallel beam of light rays. To understand about parallel beam of light rays observe situation 1.

Situation-1 :

1. Take a plank and cardboard.
2. Make small slits on cardboard.
3. Keep the cardboard on the plank perpendicular to it.
4. Keep it in sunlight during afternoon as shown in figure.
5. The light rays from the sun fall on the cardboard and passed through the slits.
6. We can observe that the light rays are travelling parallel to each other. These are called parallel beam of light rays.

ii) Converging beam of light rays :
“Light rays which travel from different directions to meet at a point are called as Converging beam of light rays”.
To know clearly about converging beam let us observe situation 2.

Situation-2 :

1. Recall the above situation.
2. Arrange an acrylic mirror in the path of light rays as shown in the figure.
3. The light rays meet at a point after bouncing back from the mirror. These are called converging beam of light rays.

iii) Diverging beam of light rays :
“Light rays which travel from a source moving in different directions are called as Diverging beam of light rays.” To understand about diverging beam, let us observe situation 3.

Situation-3 :

1. In the above situation, arrange the acrylic mirror in the path of light rays as shown in the figure.
2. After bouncing back from the mirror light rays travel in different directions

Activity – 2

Question 2.
Write an activity to Understand the reflection of light.
Answer:
“The process of bouncing back of light rays into the same medium after falling on a smooth or rough surface from the light source is called “reflection of light”. Let us understand this phenomenon with the following activity.

1. Take a torch and enter into a dark room.
2. Observe the objects in darkness. We cannot see any object.
3. Switch on the torch and focus it on the objects. We can see the objects.
4. Keep a card board between your eyes and object.
5. Now try to see the objects. We cannot see any object. ,
6. From the above activity we can conclude that objects are visible only when light falls on the objects and bounces back to the eye.

Activity – 3

Question 3.
Write an activity to understand the reflection of light.
Answer:

1. Take a plane mirror and stand infront of a building in open space during the day.
2. Let the sunlight falls on the mirror.
3. Now, rotate the mirror in such away that a spot of light falls on the wall of building.
4. Light rays from the sun fall on the mirror and bounced back. The spot of Light on the wall is the image of sun.
5. In this activity, light rays fall on the mirror and bounced back.
6. This process of bouncing back of light rays in the same medium after hitting the surface of an object is called reflection.

Activity – 4

Question 4.
Write an activity to understand the regular reflection and irregular reflection of light.
Answer:
Reflection from a smooth and shiny surface is called regular reflection.

Reflection from an irregular or uneven surface is called irregular reflection or diffused reflection.

Let us understand these from the activity below.

1) Focus the light from a source on the objects mentioned in the given table and try to get the image of the objects.

2) Record your observations in the table given.

Object	Nature of surface of the object (Smooth and shiny/ Smooth but not shiny/ rough)	Observation (Clear image is formed/image is formed but not clear/ No image is formed)
1. Plane mirror	Smooth and shiny	Clear image
2. New steel plate	Smooth and shiny	Clear image/ but not clear
3. Card board	Rough	No image
4. Thermocol sheet	Rough	No image
5. Cloth	Rough	No image
6. Paper	Rough	No image

3) From the above table it is clear that light reflects regularly from a smooth and shiny surface and irregularly from an uneven surface.

4) Reflection from a smooth and shiny surface is called regular reflection.

5) Clear images are formed in case of regular reflection.

6) Reflection from an irregular or uneven surface is called irregular reflection or diffused reflection. Images are not clear or sometimes cannot form the images at all in case of irregular reflection.

Activity – 5

Question 5.
How can you verify the laws of reflection?
Answer:

1. Take a White paper and spread it on a drawing board or cardboard.
2. Draw a straight-line AB at the center of paper by a pencil.
3. Mark a point O at the center of AB.
   
4. At the point ‘O’ draw a perpendicular line ON to AB.
5. ON is called normal to the surface.
6. ake a protractor and place it on white paper in such a way that the zero edge of the protractor coincides with the point O on AB as shown in figure.
7. Mark different angles starting from 10° to 80° on both sides of ON.
8. Now place a plane mirror on the line AB with the help of two clips such that the surface of the plane mirror is perpendicular to the surface of the white paper.
9. Take a laser pointer and focus it on plane mirror at ‘O’ making an angle of 40° with the line ON.
10. Observe the reflected ray from the mirror.
    

    Angle of incidence	Angle of reflection
    1. 20°	20°
    2. 40°	40°
    3. 60°	80°
    4. 80°	80°

11. The angle made by incident ray with the normal ON is called angle of incidence i.
12. The angle made by the reflected ray with the normal is called the angle of reflection r.
13. Focus laser pointer at different angles of incidence.
14. Observe the angles of reflection in each case and tabulate the values.

From the above observations you can conclude that the angle of incidence is always equal to angle of reflection.
(OR)

This is the first law of reflection.
1) From the above activity you can also observe that Incident ray, reflected ray and normal are present in the same plane and incident, reflected rays are on either side of normal.

2) The incident ray, reflected ray and normal to the surface are present in the same plane and incident, reflected rays are on either side of normal.
This is the second law of reflection.

Activity – 6

Question 6.
How can you verify the following characteristics of image by plane mirror?
1) Object distance is equal to image distance.
2) Size of the object is equal to size of the image.
Answer:
Let us verify the above characteristics by the following activity.
1) Take a chess board.
2) Fix a plane mirror vertically at the one end of the chess board as shown in the figure. Place a sharpener on one of the square boxes on the chess board.
3) You can see the image of sharpener in the mirror.

4) Count the number of square boxes between the mirror and the sharpener. At the same time count the number of square boxes between the mirror and the image of sharpener. The number of square boxes equal in both the cases.
Conclusion 1:

5) From the above activity you can conclude that the distance of the object from the mirror is equal to the distance of image from the mirror.

6) The distance of the object from the mirror is called object distance. The distance of the image from the mirror is called image distance.

7) In the above activity observe the size of object [sharpener] and image.

8) You will find that the size of image and object are equal.

Conclusion 2:
From the above activity you can conclude that the size of the object is equal to size of the image.

Activity – 7

Question 7.
How can you verify the following characteristic of image by plane mirror?
Laterally inverted image is formed, (left and right alternates)
Answer:

1. Stand in infront of a plane mirror and raise your right hand.
2. Observe the image formed in the mirror.
3. Now lower the right hand and raise the left hand.
4. Observe the changes you noticed in the image.
5. Your right hand appears left and left hand appears right in the image.
6. Such a shift of lateral side of images in opposite direction is called lateral inversion.

Conclusion:
So images formed by plane mirrors undergo lateral inversion

Activity – 8

Question 8.
How can you verify the following characteristics of image by plane mirror?
* The image formed is always virtual and erect.
Answer:

1. Place a burning candle infront of the plane mirror.
2. Observe the image of burning candle in the mirror.
3. Now place a white paper behind the candle.
4. Try to get the image of candle on paper.
5. If your answer is ‘YES’, such type of image which we get on screen is called real image.
6. If your answer is ‘NO’, such type of image which cannot get it on screen is called virtual image. •
7. Plane mirror forms only virtual image.
8. In the above activity, the image of burning candle is erected.
9. We can see the erect image of the object in the mirror.

Conclusion:
Thus, we can conclude that plane mirrors form virtual and erect image.

Activity – 9

Question 9.
Write an activity to understand the relation between the arrangement of mirror and number of images.
(OR)
Derive a formula for number of images formed between two mirrors.
Answer:

1. Take a drawing board, spread a white sheet on it.
2. Draw a semicircle on the white sheet.
3. Mark the angles from 0° to 180° with the help of protractor.
4. Take two plane mirrors of same size join them with cellophane tape as shown in the figure.
5. Keep the mirrors on the semicircle such that the angle between the mirrors is 120° .
6. Now bring a burning candle in between the mirrors.
7. Observe the number of images formed by the two Mirrors.
8. Change the angles between the mirrors from 120° to 90°, 60°, 45°, and 30° respectively.
9. Observe the number of images formed in each position. Tabulate your observation.

In this way we. can derive the formula to find out the number of images formed between two mirrors.

Number of images (n) = (360°/θ) -1 where 0 is the angle between the mirrors

Activity – 10

Question 10.

How do you make a Royal Road in a Shoe Box by using plane mirror?
(OR)
How do you prepare a Fancy item by using the phenomena of multiple reflections of plane mirrors?
Answer:

1. Fix two plane mirrors on the opposite sides of a shoe box with their reflecting surfaces facing each other.
2. Draw a road on the bottom of shoe box between the mirrors.
3. Arrange two LED street lights on both sides of road.
4. Make a small hole on mirror side of shoe box and scrape off a little of colour coating from the mirror on that place.
   Observe the scenery inside the box through this hole.
5. Light rays from the LED fall on the first mirror and then continuously undergone multiple reflections.
6. That’s why we see a long road With full of LED lights.

Activity – 11

Question 11.
How do you make a periscope by using plane mirrors?
(OR)
Make your own periscope.
Answer:
Required materials:
Empty Incense stick box [Agarbatt(box], two mirror strips, scale, pencil, blade, gum.

Procedure:

1. Take an empty Incense stick box.
2. Close the ends and draw two squares at both the ends by using scale and pencil.
3. Draw diagonals to the square boxes, such that the two di-agonals facing each other.
4. Make two slits with the help of blade along the diagonals.
5. Make sure that the size of mirror should be equal to the length of slits.
6. Fix the mirror strips in the slits in such a way that reflecting surfaces of mirror strips face each other.
7. Fix the mirror strips firmly to the box by using gum.
8. Cut out two windows on the narrow sides such that the windows should open directly on the reflecting surfaces of the mirror strips as shown in figure.
9. Now your Periscope is ready.
10. You can use this to see the objects outside the room through the window while hiding yourself in the room

Activity – 12

Question 12.
Write an activity to understand different shapes of spherical mirrors.
Answer:

1) Take a stainless-steel serving spoon.
2) Look into it by bringing the outer bulged side of the spoon near your face.
3) Do you see your image in it? (Yes)
4) Did you observe any difference in image from what you see in plane mirror? (Yes)

10) Try to increase the distance of the spoon from your face.
11) Here the surface of the spoon act as a mirror but the surface is not plain.
12) The outer surface of the spoon is curved out like the outer surface of a sphere.
13) The inner surface of the spoon is like the part of inner surface of a sphere.
14) These mirrors are the parts of spheres. So these kinds of mirrors are called spherical mirrors.

Spherical mirrors are of two types :

1. Convex mirrors (Reflecting surface bent outward)
2. Concave mirrors (Reflecting surface bent inward)

Activity – 13

Question 13.
Characteristics of image formed by a concave mirror.
Take a ‘V’ shaped wooden stand. Keep a concave mirror on it. Place a lighted candle at a distance of about 50 cm in front of the mirror. Try to get clear image of the candle flame on a white screen or white paper by moving the screen towards and away from the mirror. Make sure that the screen is not placed in between burning candle and mirror.

Place the lighted candle at different distances in front of the mirror by moving it towards the mirror. Try to get clear image on screen at each position. Note your obser-vation in the table given below.
Answer:

From the above table you can conclude that a concave mirror can form real and virtual images, erect and inverted images, smaller, same size and bigger images depending on the position of object in front of it.

SCERT AP 7th Class Science Study Material Pdf 5th Lesson Motion and Time Textbook Questions and Answers.

AP State Syllabus 7th Class Science 5th Lesson Questions and Answers Motion and Time

7th Class Science 5th Lesson Motion and Time Textbook Questions and Answers

Improve Your Learning

I. Fill in the blanks.

1. Units of speed is _____
2. If a body covers equal distances in equal intervals of time, it is said to be _____ motion.
3. 60 minutes = _____ seconds. (3600)
4. Average speed = total distance travelled / _____
5. ISRO stands for _____
6. Geostationary satellites are used for _____ purpose.
Answer:
1. m/s
2. uniform
3. total time taken to travel
4. Indian Space Research Organization
5. Communication

II. Choose the correct answer.

1. The correct relation between speed, distance and time is
a) Speed = distance / time
b) Speed = time / distance
c) Time = speed/ distance
d) Distance = speed / time
Answer:
a) Speed = distance / time

2. What is common in the following?
Motion of the propeller of a flying helicopter, the hands of a watch, motiob of a giant-wheel.
a) All are examples of translatory motion
b) All are examples of oscillatory motion
c) All are examples of rotatory motion
d) a & c
Answer:
c) All are examples of rotatory motion

3. Which of the following is not an oscillatory motion?
a) Motion of the hammer of an electric bell.
b) Motion of your hands while running.
c) Motion of a child on a see – saw.
d) Motion of a horse pulling a cart.
Answer:
d) Motion of a horse pulling a cart.

4. Which of the following statements is not correct?
a) The basic unit of time is second.
b) Every object’s motion is Uniform.
c) 1 km/h = 5/18 m/s.
d) Speed is expressed in km/h.
Answer:
b) Every object’s motion is Uniform.

III. Matching

A) Rotatory Motion	1. Rocket
B) Oscillatory Motion	2. A train entering into a railway station
C) Translatory Motion	3. Movement of needle in a sewing machine.
D) 100 years	4. Decade
E) 10 years	5. Movement of hands in a wrist watch.
	6. Century

Answer:

A) Rotatory Motion	5. Movement of hands in a wrist watch.
B) Oscillatory Motion	3. Movement of needle in a sewing machine.
C) Translatory Motion	2. A train entering into a railway station
D) 100 years	6. Century
E) 10 years	4. Decade

IV. Answer the following

Question 1.
The distance between two stations is 240km. A train takes 4 hrs to cover this distance. Calculate the speed of the train m/s.
Answer:
The distance between two stations = 240 km
Time taken to cover this distance = 4 hrs
Speed of the train = distance / time
= 240/ 4 km/hrs
= 60 km/hrs

This is the speed of the train in km/hrs,
to convert it into m/s….

Question 2.
Can an object possess translatory and rotatory motion at the same time? Give an example.
Answer:

1. Yes. An object can possess both translatory and rotatory motions at the same time.
2. When we observe the motion of a cycle tyre moving in a straight line, all the parts of tyre moves in the same direction of cycle so, we can say it is in translatory motion.
3. If we observe the rolling of cycle tyre, it move in a curved (circular) path about a iron rod in the middle of the wheel as an axis. So, we can say it is in rotatory motion.
4. In this way the cycle tyre moving in a straight line possesses both translatory, and rotatory motions.

Question 3.
In a sewing machine used by tailors, mention the type of motion of its parts when it runs, a) the wheel b) the needle c) the cloth
Answer:

Parts of sewing machine	Type of motion
The wheel	Rotatory motion
The needle	Oscillatory or vibratory motion
The cloth	Translatory motion

Question 4.
Write the motion of different parts of a bicycle while it is in motion, a) the wheels b) the cycle chains c) the pedal with its arm d) the movement of the rider along with the bicycle.
Answer:

Parts of a bicycle	Type of motion
The wheels	Rotatory and translatory motions
The cycle chains	Translatory motion (curvilinear motion in elliptical path)
The pedal with its arm	Rotatory motion
The movement of the rider along with the bicycle	Translatory motion

Question 5.
John tied a stone to a string and whirled it around. What type of motion do you observe?
Answer:
When a stone is tied to a string and whirled it around, it move in a circular path around the hand. That means the stone fallows a curved path with respect to the hand as a fixed centre or axis of rotation. So it is said to be in rotatory motion.

Question 6.
What are Uniform and Non-Uniform motions? Give four examples for each type of Motions.
Answer:
i) Uniform motion : “If a body covers equal distances in equal intervals of time, it is said to be in uniform motion”.
Ex: 1. Hands of a clock
2. Revolution of Earth
3. A train going at a steady speed
4. The blades of a fan

ii) Non-uniform motion: If a body covers unequal distances in equal intervals of time, it is said to be in non-uniform motion.
Ex : 1. Movements of butterfly in a garden
2. The motion of a car in a city traffic
3. An aircraft while landing
4. Running of athletes in a marathon

Question 7.
Your friend told you the motion of rocket is fast motion. Will you agree? How can you decide whether the motion of a body is slow or fast?
Answer:

1. Yes. I agree with him. Because rockets move with the speed of 12 km per second. Its very high speed.
2. The distance travelled by an object in a given interval of time can help us to decide whether it is faster or slower.
3. The distance travelled by an object in a unit time is called as its Speed.
4. Speed = Distance travelled / Time taken to travel.
5. Units of speed is meter per second (m/s) or kilometre per hour (Km/h).
6. 1 Km / h = 5/18 m/s
7. The object moving with less speed is slow and more speed is fast. Thus we can decide whether the motion of a body is slow or fast using its speed.
8. At a particular instant of time, we can find speed of a vehicle using speedometer.

Question 8.
How can you appreciate the clocks and watches in measuring or estimating time?
Answer:

1. Clocks and watches are helpful to us in measuring or estimating time.
2. They help us in scheduling our works properly.
3. They help us in attending the works on time by displaying the time.
4. With out clocks and watches its very difficult to estimate the time.
5. Sometimes they are used to make a loud alert signal at a specified time to make us wake up or recall a work.
6. Some times they are helpful in measuring the time also.
7. Now a days they are.available in some other gadgets like mobile phone also.
8. Thus they become an essential and integral part of our life.

7th Class Science 5th Lesson Motion and Time InText Questions and Answers

7th Class Science Textbook Page No. 68

Question 1.
What do you observe from the picture?

Answer:
You can see the movement of cars, buses, train, boat, clouds, birds and minute hand in the clock etc. On the other side we can see the bridge, buildings, road, hill and the clock tower which are not moving.

7th Class Science Textbook Page No. 69

Question 2.
Do all these things move alike?
Answer:
No.

Question 3.
What makes the objects move and moving object to come to rest?
Answer:
Force makes the objects move and moving object to come to rest.

Question 4.
What do we call the motion of a train moving in a straight line?
Answer:
Translatory motion.

Question 5.
Is the forward movement of birds and the movement of its wings same?
Answer:

1. Not same.
2. Forward movement of birds is a translatory motion and wing movement is an oscillatory motion.

Question 6.
How do you decide whether any object is in motion or at rest?
Answer:

1. Motion is a common experience in our life.
2. We feel an object is in rest when it is not changing its position and we fee! an object is in motion when it is changing its position with respect to the surroundings.

Question 7.
Are all these trees, buildings, electric poles, etc. really in motion?
Answer:
No.

Question 8.
Which one do you feel is moving, passenger in the bus or tree?
Answer:
Passenger.

Question 9.
Which one do you feel is moving, tree or your co-passenger?
Answer:
Tree.

Question 10.
Why is it so?
Answer:
Motion and rest are relative terms and ‘hey are relative to the observer. We feel an object is at rest when it is not changing, its position. We feel an object is in motion When it is changing its position with respect to the surroundings.

7th Class Science Textbook Page No. 70

Question 11.
Have you ever played carrom board? What is the reason for movement of coins when we hit them with a striker?
Answer:
The force applied by the striker on the coins is the reason for movement of coins.

Question 12.
How force effects the motion?
Answer:
Force can change the position of motion to rest, of vice – versa.

7th Class Science Textbook Page No. 71

Question 13.
What did your friend apply to make the ball move?
Answer:
Force (muscular force).

Question 14.
What did you apply to change the direction of the ball?
Answer:
Force (muscular force).

Question 15.
What did your friend apply to stop the moving ball?
Answer:
Force (muscular force).

Question 16.
What can we call the length of path that an object moves from one place to another?
Answer:
Distance.

Question 17.
Ouserve the picture, Kavitha can reach her school in two ways. From A, B roads which path will you suggest her to reach the school early? You will suggest the shortest distance pat*” which is road A.

Answer:
Road A

7th Class Science Textbook Page No. 72

Question 18.
What can we call the duration of motion of the object when it is moving from one place to another place?
Answer:
Time to travel

Question 19.
How can we call the period between starting and ending incidents (events) in a running race.
Answer:
Time.

Question 20.
How do we measure or estimate time?
Answer:
Clocks (watches) are the most common time measuring devices.

7th Class Science Textbook Page No. 73

Question 21.
Are all the motions same?
Answer:
No, all the motions are not same.

Question 22.
How many types of motions are there?
Answer:
Motion is of three types :

1. Translatory motion
2. Rotatory motion
3. Oscillatory motion.

Question 23.
Have you played with a toy car? How does it move if you push it forward?
Answer:
It moves in translatory motion.

Question 24.
Do all the parts of bus like wheels, headlights, windows etc., move through the same distance from building ‘A’ to building ‘B’?
Answer:
Yes, all parts of the bus moves along the bus.

Question 25.
Is the direction of motion of bus along a straight line or a curved line?
Answer:
In a straight line.

7th Class Science Textbook Page No. 74

Question 26.
Can you give some more examples of motion in which all points of moving body move through same distance in the same direction?
Answer:
Examples:

1. Coconut falling from a tree.
2. Movement of lift.
3. Car travelling on a straight road.
4. Movement of water from the tap.

Question 27.
If all the parts of a body move along the curved path. What type of motion it is?
Answer:
Rotatory motion.

Question 28.
Observe the following diagrams.

1) Do you find any similarity in the above motions?
2) What is the path of motion of each part of the body that moves? ’
Answer:

1. In the above situations, the parts of the objects move in a curved path with respect to a fixed centre or a fixed axis.
2. They are in rotatory motion with circular path.

7th Class Science Textbook Page No. 75

Question 29.
Can objects have simultaneous Translatory and Rotatory motions?
Answer:
Yes. The cycle tyre moving in a straight line possesses both translatory and rotatory motions.

Question 30.
Have you played with a see-saw? How does it move?
Answer:

1. See – saw moves in up and down direction with a fixed point.
2. This type of motion is called oscillatory motion,

Question 31.
How does the needle of swing machine moves?
Answer:
The needle of a sewing machine moves in ‘to and fro’ motion or back and forth motion.

7th Class Science Textbook Page No. 76

Question 32.
Which similarity do you find in the moving parts of the above instruments?
Answer:
All are moving in ‘to and fro’ motion.

Question 33.
Is the direction of motion constant? Are they moving in the same path again and again?
Answer:

1. The direction of motion of the objects changes alternatively along the same path about a fixed point. Hence the direction of motion of the object not constant.
2. Yes, they are moving in the same path again and again.

Question 34.
Does all motions take same time to cover same distance?
Answer:
No.

7th Class Science Textbook Page No. 77

Question 35.
Do you find any relation between distance and time?
Answer:
Yes, distance divided by time give speed the objects.

Question 36.
How to calculate the average speed?

Question 37.
Is there any other method to express the motion of objects?
Answer:
Yes, we can express the motion of objects by graphs.

7th Class Science Textbook Page No. 78

Question 38.
Have you seen launching of rocket in T.V, how does it move?
Answer:

1. Rockets move in translatory motion.
2. The exhaust gases coming out of the engine’s nozzle at the high speed push the rocket forward.

Question 39.
Do you know which Indian organization is working for it?
Answer:
ISRO (Indian Space Research Organization) is working for it.

Question 40.
Where do these rockets are launched?
Answer:
Rockets are launched at Satish Dhawan Space Centre (SDSC – SHAR), Sriharikota, Andhra Pradesh.

7th Class Science Textbook Page No. 80

Question 41.
Have you noticed what happens if you let the air out of a inflated balloon?
Answer:
The air comes out of balloon in one direction and the balloon moves on the opposite direction with the same speed.

Question 42.
Have you observed the movement of Diwali rocket cracker?
Is there any similarity between movements of rocket cracker and real rocket?
Answer:

1. Diwali rocket cracker takes flight, when it is fired.
2. Motion of the actual rocket is similar to it.

Question 43.
Have you ever feel wonder of knowing weather report in advance?
Answer:
Yes, weather report forecasting in advance is possible because of artificial satellites.

Question 44.
How google maps give route maps between two places?
Answer:

1. Google maps is a internet based application to show maps and roots between two places.
2. They map our location with the pictures and data provided by artificial satellites.
3. By using artificial intelligence, they integrate the information and give route maps between two places.

Activities and Projects

Question 1.
Use a tennis ball or cricket to make it translatory motion, rotatory motion, and oscillatory motion. Write a note on it and discuss with your friends.
Answer:

1. I took a tennis ball and throwed it towards my friend to catch it. The motion showed . by ball is translatory motion.
2. Spun the ball on my finger. It shows rotatory motion.
3. Now it is rolled over the ground towards my friend. It shows both translatory and rotatory motions.
4. Now tied this ball to a thread and moved forward and backward. This shows the oscillatory motion.

Question 2.
Make a water clock or a sand clock and use it to know time.
Answer:

1. I took two, clear plastic bottles that are the same size and shape.
2. Took the caps off, glued them together, and let the glue dry.
3. I Punched a hole through the middle of the glued-together caps.
4. Screwed the cap onto the first bottle, just like we normally would.
5. Filled the second bottle with dry sand.
6. Screwed the empty bottle onto the sand-filled bottle.
7. Tested my sand timer by turning it upside down to know whether the sand is flowing smoothly from one bottle to the next or not.
8. Marked the time on the bottles at various levels of sand by observing the time using stop watch.
9. Wrapped some tape around the neck.
10. My sand clock is ready to use.

Activities

Activity – 1

Question 1.
Classify the objects given in the figure based on motion and rest and what is your inference?

Objects at rest	Objects in motion

Answer:

Objects at rest	Objects in motion
Bag	Butterfly
Table	Bird
House	Merry – go-round

Inference:

1. “An object is said to be in motion if it changes its position with respect to its surroundings.”
2. “An object is said to be at rest if there is no change in its position with respect to its surroundings.”

Activity – 2

Question 2.
How do you show that force is required to change the object from rest into motion, to change its direction and even to change from motion to rest?
Answer:

Take a football and go to your school ground with your friends. Stand in a triangle shape as shown in the figure.Ask your friend to kick the ball in your direction. You pass the ball to another friend. Ask him to stop that ball. Now answer the following questions.
1) What did your friend apply to make the ball move?
Answer:
Force

2) What did you apply to change the direction of the ball?
Answer:
Force

3) What did your Mend apply to stop the moving ball?
Answer:
Force

You all applied muscular force with your legs to do so.

From the above observation we can say that force is required, to change the object from rest into motion, to change its direction and even to change from motion to rest.

Activity – 3

Question 3.
Write any activities to explain the distance and displacement.
Answer:
Try to measure the distance between your bench to the place where MDM is been served in your school.

How much it is? (Student has to measure and answer on their own)

Have you ever used the google maps to know the distance and direction of your desti-nation?

Now, know the distance between your native place to district head quarter using google maps?

How much it is? _____ km. (Student has to measure and answer on their own)

Observe the picture, Kavitha can reach her school in two ways. From A, B roads which path will you suggest her to reach the school early? You will suggest the shortest distance path which is road A.

From the above activity and examples, we can say that when an object travels from one place to another, the length of the path can be measured and it gives the distance between the two places. When an object travels along the straight-line path from one place to another place, it will reach faster. The length of the straight-line path is the shortest distance between two places, called displacement.

Activity – 4

Question 4.
Conduct 100 meter running race with the help of your physical education teacher. Use stop watch from lab or mobile phone to measure time taken to complete the race by each student. Fill the table given below.

Answer:

Name of the student	Time taken to complete race
1. Satyam	1 m 5 sec
2. Venkatesh	53 sec
3. Rama Raju	46 sec
4. Balakrishna	1m 12 sec
5. Narendra	58 sec
6. Vijay	1 min

[Note : Fill in the table with your records)

Activity – 5

Question 5.
Consider the following situation. Robert and Kamala measured the distance trav¬elled while coming to school and the time taken to cover that distance. Their data is shown in the Table. You can draw a graph by following the steps given below:

Time (Minutes)	Distance (Meters)
1. 0	0
2. 1	100
3. 2	200
4. 3	300
5. 4	400
6. 5	500

Answer:
1) Draw two perpendicular lines to represent the two axic anti mark them as OX and OY. Mark OX as time axis and OY as distance axis.

2) Choose a scale to represent distance and time on the graph.
Time : 1 min = 1 cm.
Distance : 50 m = 1 cn

3) Mark values for the time and the distance on the respective axis according to the scale you have chosen.

Now you have to mark the points on the graph paper to represent each set of values and, join al! the points on the graph. This is the distance-time graph for the given motion.

4) If the distance-time graph is a straight line, it indicates that the object is moving with a constant speed. However, if the speed of the object keeps changing, the graph can be of any other shape. From the distance-time graph we can find the speed of object.

From the distance-time graph we can find the speed of object.

SCERT AP 7th Class Science Study Material Pdf 11th Lesson Soil and Water Textbook Questions and Answers.

AP State Syllabus 7th Class Science 12th Lesson Questions and Answers Soil and Water

7th Class Science 12th Lesson Soil and Water Textbook Questions and Answers

Improve Your Learning

I. Fill in the blanks.

1. Waste water released from houses is called _______ .
2. The Science dealing with the formation of soil is called _______ .
3. In modern water purifiers _______ are used instead of chlorine to kill the germs.
Answer:
1. Sewage
2. Pedology
3. Ultraviolet rays

II. Choose the correct answer.

1. In addition to the soil particles, the soil also has
a) air and water
b) water and plants
c) minerals, organic matter, air and water
d) water, air and plants
Answer:
c) minerals, organic matter, air and water

2. The water holding capacity is the highest in
a) sandy soil
b) clayey soil
c) loamy soil
d) mixture of sand and loam
Answer:
b) clayey soil

3. Which among the following is not responsible for water shortage?
a) Industrial growth
b) Population growth
c) Heavy rainfall
d) Mismanagement of water resources
Answer:
c) Heavy rainfall

III. Matching.

A) Weathering	1. more water retaining capacity
B) Clay soil	2. washing off the top soil
C) Soil erosion	3. soil formation
D) Afforestation	4. 1%
E) Fresh water	5. growing trees
	6. 99%

Answer:

A) Weathering	3. soil formation
B) Clay soil	1. more water retaining capacity
C) Soil erosion	2. washing off the top soil
D) Afforestation	5. growing trees
E) Fresh water	4. 1%

IV. Answer the following questions

Question 1.
Explain briefly the terms.
i) Weathering ii) Aquifer iii) Percolation iv) Sewage
Answer:
i) Weathering :

1. In nature due to the action of various natural agents such as wind, water, sun and climate the bigger rocks (parent rock) gradually breakdown and give small particles. These form the soil. This process is known as Weathering.
2. It takes approximately 500 -1000 years for the formation of 1 inch of soil.
3. Weathering helps in the formation of soil.
4. The process of formation of soil from the parent rock by the process of weathering is called ‘Pedogenesis’.

ii) Aquifer :

1. Ground water is stored between layers of hard rock below the water table. This is called aquifer.
2. The wells, tube wells and hand pumps get water present in the aquifer.

iii) Percolation :

1. The absorption and downward movement of water through the soil layer is called percolation.
2. The rate of percolation various from soil to soil.
3. Sandy soils are well aerated and they have high percolation rate.

iv) Sewage :

1. All the waste water released by homes, industries, hospitals, offices and other users are collectively called sewage.
2. Sewage is a liquid waste.
3. Sewage contain water with dissolved and suspended impurities, disease causing bacteria and other microbes. These impurities are called contaminants.
4. Discharge of untreated sewage into canals causes harm to aquatic life.

Question 2.
List the differences between clayey soil, loamy soil and sandy soil. How is clayey soil useful for crops?
Answer:

1. Clayey soils are less aerated and their water holding capacity is higher.
2. It has finer particles less than 0.002 mm. Hence, they retain the water for a longer period.
3. Clayey soils are very suitable to grow crops like paddy. Sugarcane and cotton. Black soil with highest clay are suitable to grow crops like redgram. chillies etc.

Question 3.
Harshith observed that majority of the houses in his locality get water through bore well but no house has taken measures for rain water harvesting. Guess the long term effect on the water table.
Answer:

1. Over use of ground water can cause wells to dry up.
2. This leads to expensive and ultimately fertile attempts to keep up with the dropping water table by drilling deeper and deeper wells.
3. People will have to travel for miles to get water for their daily use.
4. People will migrate to longer distances in search of drinking water and villages would become barren.

Question 4.
If you get a chance to interview a soil scientist, what questions will you ask related to soil, its testing and conservation.
Answer:
I shall ask the following questions.

1. How can you test the soil for its acidity?
2. Is it possible to change the basic nature of the soil?
3. How can the water holding capacity of the soil be increased at a low cost?
4. Suggest methods to improve the fertility of the soil.
5. What can be done with the black cotton soil when a building is to be constructed?
6. As black cotton soil yields, and the building cracks, suggest preventive measures for it.

Question 5.
Your friends conducted an experiment in the field regarding the rate of percolation. They observed that it took 40 min for 200 ml of water to percolate through the soil. Calculate the rate of percolation. Also write the procedure to conduct the test.
Answer:

Procedure :

1. Take a soil sample.
2. Take a plastic funnel and place a filter paper in it as shown in the figure.
3. Weigh 50 gms of dry soil and pour it into the funnel.
4. Take 200 ml of water in a measuring cylinder.
5. Then pour the water on the soil drop by drop.
6. Pour the water all over the surface of the soil until it starts dripping out of the funnel. Calculate the time taken for the last water drop passes down the soil.

Question 6.
We call earth as “Bhoomatha -The Mother Earth”. How do you express your appreciation and gratitude to her?
Answer:

1. Soil is one of the most important natural resources. It supports the existence of living organisms.
2. We use soil for different purpose in our daily life. Almost all living things in our surroundings directly or indirectly depend on soil.
3. The soil supports all plants, animals and micro organisms.
4. We grow our food components in this soil.
5. Soil is the birth place of all minerals, everything we get from this soil. Hence, we consider the earth as “Bhoomatha – The Mother Earth”.

Question 7.
Poorvika wants to maintain a garden,- what suggestions can you give her to minimize the use of water and also to improve the soil quality?
Answer:

1. By using sprinklers and drip irrigation methods we can reduce the wastage of water in the garden.
2. Construction of soaking pits in the garden enhances the percolation of raia water into the soil. It improves the ground water table.
3. Rotting vegetation and animal remains make up the humus rich in fertility.
4. They contain nutrients, natural manure, which give good support to the growth of ‘ plants.
5. I also suggest Poorvika to grow big trees around the garden to stop winds.
6. It is better to grow grass and other plants in the vacant portions of the garden. These grass plant roots hold the solid particles and prevent soil erosion during heavy rains.

7th Class Science 12th Lesson Soil and Water InText Questions and Answers

7th Class Science Textbook Page No. 84

Question 1.
Where do animals and humans live?
Answer:
They live on the Earth.

Question 2.
What would happen if there is no soil on the Earth?
Answer:
Life on the earth would become impossible.

Question 3.
Why is woman in the picture using hand pump?
Answer:
For getting drinking water.

Question 4.
Why is soil an important resource?
Answer:
It is the important natural resources necessary for life on the earth. Human beings, plants and micro organisms depend on soil for their basic needs.

Question 5.
Where do plants get nutrients from?
Answer:
From soil.

Question 6.
Did you ever see earthworms and snails coming out of soil during rainy season?
Answer:
Yes, they live in the soil by making burrows.

7th Class Science Textbook Page No. 85

Question 7.
Is soil useful to us in any other way?
Answer:
Yes, soil is also needed.

1. For agriculture
2. For constructing buildings
3. For making toys and idols
4. For making utensils and pottery
5. For making cosmetics (multani soil)

Question 8.
Did you observe stones of different sizes at the bank of a stream?
Answer:
Yes. I observed many stones with different sizes and shapes.

Question 9.
What happens when rocks get rubbed and scroll due to the flow of water?
Answer:
Weathering of rocks takes place.

Question 10.
You might have observed white coloured crinkles on the rocks at the bank of river. How do they appear?
Answer:
They appear like shining jewels. They are formed by the disintegration of rock due to the abarsion of water stream.

Question 11.
Have you observed the top soil in your surroundings? What is it made of?
Answer:
Yes. It is made of dead and decayed organic matter called Humus.

7th Class Science Textbook Page No. 86

Question 12.
What do you observe floating on the top?
Answer:
Humus.

Question 13.
What do you find at the bottom of the beaker?
Answer:
Inorganic matter of the soil.

Question 14.
Do you find any insects and plant parts in the beaker?
Answer:
Yes, they are floating. It is the organic matter of the soil.

Question 15.
What do you infer from your observation?
Answer:
We can infer that soil consists of water, air, organic matter, inorganic matter and organisms.

Question 16.
How many layers did you observe in the pit?
Answer:
Two layers can be observed in the pit.

Question 17.
Do all the layers have same colour, texture and depth?
Answer:
No, all the layers have different colour, texture and depth.

7th Class Science Textbook Page No. 87

Question 18.
How can you identify which soil is suitable for this purpose?
Answer:
Clayey soil is suitable for making Ganesh idol.

7th Class Science Textbook Page No. 88

Question 19.
Do all types of soils have same properties?
Answer:
No, they have different properties.

7th Class Science Textbook Page No. 89

Question 20.
What type of soils are generally seen in our state?
Answer:
Sandy soils, black soils, red soils, loamy soils are seen in our state.

Question 21.
Can we grow a crop in all types of soil?
Answer:
No, it is not possible.

Question 22.
What type of soil is required for growing paddy?
Answer:
Paddy is grown in clayey soil, which retains water for a longer period.

Question 23.
Is there any relationship between the crops and soil?
Answer:
Yes, all crops are not grown in all soils. Crops are soil specific. For example cashew is grown in sandy soils and cotton is grown in black soils.

7th Class Science Textbook Page No. 90

Question 24.
Why is soil testing done?
Answer:
It helps a farmer to make a soil suitable for growing crops.

Question 25.
How do the farmers benefit by soil testing?
Answer:

1. Soil testing helps the farmer to know about the current health of the farm’s soil and how to improve it.
2. It helps farmers to prevent the degradation of soil quality.
3. It helps to minimize usage of fertilizers.

Question 26.
Did you observe that after heavy rain, the top soil get washed off?
Answer:
Yes. I observed it during rainy season.

Question 27.
What will happen if the top soil is washed off?
Answer:
The soil will loose its quality and fertility.

Question 28.
How can we prevent it?
Answer:

1. By afforestation. Controlling the deforestation activities.
2. Constructing checkdams and bunds
3. Preventing over grazing of land by animals.
4. By planting trees as shelter belt to stop winds. .
5. By planned agricultural practices we can prevent soil erosion successfully.

7th Class Science Textbook Page No. 91

Question 29.
What are the other causes of soil erosion?
Answer:

1. Unplanned and excessive usage of agro chemicals
2. Over grazing of land
3. Deforestation
4. Digging the earth for construction and mining

7th Class Science Textbook Page No. 92

Question 30.
Is water from seas and oceans useful for drinking and agriculture?
Answer:
No, the sea water is not useful for drinking and agriculture. But by desalinating the sea water we can use them for consumption.

Question 31.
Where is fresh water available from?
Answer:
From rivers, lakes, streams and ravines.

Question 32.
How much percentage of fresh water is available?
Answer:
only 1%.

Question 33.
How does the water reach the ground?
Answer:
The water reach the ground by infiltration.

Question 34.
Is the water table level same at all places?
Answer:
No, it is always vary in different places.

7th Class Science Textbook Page No. 93

Question 35.
Why do wells dry up?
Answer:
Decrease in ground water table leads to dry up of wells.

Question 36.
What will happen if the ground water table go down?
Answer:
All the wells and bore wells will dry up.

7th Class Science Textbook Page No. 94

Question 37.
Why is it essential to manage the water?
Answer:
To resolve the prevailing water scarcity in the society, proper water management of water resources is very essential.

Question 38.
How can we make water fit to drink?
Answers:
By purifying the water through chemical and physical treatment.

Question 39.
What are the methods to purify water?
Answers:
Chemical and physical methods are used for treatment of water.

7th Class Science Textbook Page No. 95

Question 40.
What can we do to remove the contaminants from water?
Answers:
To remove contaminants from water, it should be treated in waste water, treatment plant.

Question 41.
Where is it done?
Answers:
Waste water treatment plant.

Think & Respond

Question 1.
You may come across some people breaking large rocks into smaller ones to make road. Is it also the weathering of rocks? Why?
Answer:

1. In natural weathering process, the parent rock is gradually breakdown into small particles by the action of air, water, sun heat, and climate. It takes 500 to 1000 years times. This helps in formation of soil.
2. The break do\yn of rocks for the purpose of constructing roads and buildings also comes under weathering.

Here, the big rocks are blown down by using dynamites. In very short time, the bigger rocks become small gravel. It is artificial weathering or man made weathering. But this will not help in the formation of soil. This leads to the rapid depletion of natural resources like hills and mounds. The natural weathering factors like wind, water, sun have no role in this artificial weathering.

Question 2.
There is huge amount of water on earth, then why is water called a precious resource?
Answer:

1. About 97% of water is present in seas and oceans which is not useful for drinking and agriculture.
2. 2% of water is present in the form of rain, snow, sleet and precipitated water which is not available for consumption.
3. Hence only 1% of fresh water is available in the form of surface and ground water sources. This 1% of water is useful for drinking, domestic usage and agriculture.
4. Hence, we have to use this 1% of fresh water wisely and judiciously. This water is basis of life and human civilization. So, water is life. Save water save lives.
5. So, we considered water as a precious resource.

Activities and Projects

Question 1.
Under the guidance of your teacher collect the wet waste from Mid Day Meal preparation and make Vermi compost for your school garden.
Answer:

1. With the help of my science teacher, we constructed 10 × 1 × 1/2 meters Vermi Compost beds in sheds which protect these beds from direct sunlight and rain.
2. We collected coconut, banana and sugarcane leaves. We made them into 3- 4 inches layer. This inner layer was wet with water.
3. We collected the wet waste from Mid Day Meal to fill the bed. We were careful to avoid glass, polythlene, rubber and metal objects in the bed.
4. After two weeks of making bed we kept thousand earth worms per square meter and covered the bed with Gunny bags to maintain 30 to 40% of moisture.
5. After 60 days we collected the first manure. Second time we got the manure with in 40 – 50 days.
6. By using this Vermi Compost we can reduce the investments on chemical fertilizers and other pesticides. The quality of the soil and agricultural produce increased.

Question 2.
Prepare a model of representing various horizons in the soil profile using a disposed plastic bottle, stones and soil.
Answer:

1. Take soil from your surroundings, clean d: posable plastic bottle and home made paper funnel.
2. Pour the soil into the funnel putting it on the plastic bottle.
3. Now pour some water into the bottle upto its neck. Close the end of the bottle and shake it well. The heavier particles like gravel and sand settle to the bottom of the bottle, wait for a day to get all the soil particles to settle down in the bottle.
4. After one day, you may observe that heavier particles like gravel settle at the bottom of the bottle. Above that you may find sand particles. Just above the sand particles, you may find very finer particles on the top of the bottle you will find humus floating on the surface of the water.
5. From the top, first you find humus, the plant and animal organic matter which helps the growth of plants.
6. Just below the hurhus, you find clay. Clay traps the water in the soil for the roots to absorb them.
7. Below the clay, sand and gravel, they help to drain the water quickly so that the roots don’t rot.
8. Basing on the percentage of each individual component loam soils may be classified into sandy loam, silty loam and clay loam.
9. Here, the soil taken for this project is sandy loam. Like this way, we can determine the type of soils in our surroundings.

Activities

Activity – 1

Question 1.
How do you observe the plants and small living organisms in a given soil? Write your observations in a table.

Answer:

1. I visited my school garden and the kitchen garden yesterday to observe the plants and small living things in those places.
2. I marked an area of 30 cm × 30 cm. 1 dug the soil to a depth of 4 to 6 cm in the marked area.
3. I carefully sorted out the soil and observed the presence of plants and small living organisms with the help of a hand lens.

I noted down the things 1 found in the given table.

Inference :

1. We can infer that soil consists various plants and dried plant parts etc.
2. It is a good habitat for many small organisms.

Activity – 2

Question 2.
How do you observe the different components of the soil?
Answer:
Aim : To observe the different components of the soil.

Materials required : Soil, beaker, water, polythene bag.

Procedure :

1. Collect a handful of soil sample in a transparent polythene bag and close it tightly.
2. Leave it under the sun for 2 hours we can observe some droplets of water on the inner side of the bag.
3. Fill a beaker with this handful of soil, pour water into it slowly and carefully. Fill the beaker with water and stir well the soil and water.
4. Leave it for undisturbed for some time.

Observations :
Organic substances, dry rotten leaves and roots float on water. Dead and decayed organic matter that mixes with soil is called humus.
My observations and inferences are shown in the table.

Observation	Inference
Droplets of water in the bag	Presence of water in soil
Bubbles from soil when water is poured	Presence of air in soil
Floating of dry plant parts	Presence of organic matter in soil
Particles at the bottom	Presence of inorganic matter in soil
Insects and plant parts	Presence of organisms in soil

Inference :
Soil consists of water, air, organic matter, inorganic matter and organisms.

Activity – 3

Question 3.
How do you identify the type of soil in your science lab?
Answer:

1. We can identify the different types of soils in the line diagram given below.
2. We can determine the soil on the basis of following chart.

Activity – 4

Question 4.
How do you know about soil erosion?
Answer:
Aim : To know about soil erosion.

Procedure :

1. Cut three disposable bottles sidewise and fill with soil as shown in the figure.
2. Put some sprouts of green gram or any other seeds in one bottle and water regularly.
3. Cover the second bottle with dry leaves and leave the third bottle without sowing anything.
4. After a week, the sprouts in the first bottle will grow more.
5. Now, make arrangements to collect the drained water from each bottle by arranging small vessels.
6. Now blow air and pour water slowly in each bottle.

Observation :
In the first bottle containing sprouts, less soil is blown out by air and washed off by water.

Inference :
We can infer that the top soil is washed off by water and blown out by air. Plants help to prevent soil erosion.

Activity – 5

Question 5.
What are the differences in the water table in your locality due to increase in the construction and industries nearby?
Answer:

1. The water levels in the wells are rapidly decreased.
2. Many borewells are not working due to depletion in the water table.
3. People are drilling deeper and deeper borewells to keep up with the dropping water table. It is an expensive task. Hence, they are facing financial troubles.
4. People are facing drinking water shortage in the village.
5. People have to walk for miles to get water for their usage.
6. Many people migrated to different places due to scarcity of drinking water in the village.
7. Population explosion, industrial growth, enhanced agriculture activities, deforestation, decrease in the effective area for seepage and drop in rainfall are other main reasons for the rapid decrease of water table on the earth.