NCERT Solutions Class 5 Environmental Studies Chapter 7 Experiments with water

1. Ayesha put a puffed puri in a bowl of water. Would it sink or float?

Ans. It would float.

2. You put a steel plate on water. Would it sink or float? What would happen to a spoon?

Ans. If the steel plate is put carefully over the surface of water, it would float. However, the spoon will sink.

3. Would the cap of plastic bottle cap sink or float on water?

Ans. It would float.

4. Have you seen that something float on water while of hers sink? Think how this happens!

Ans. Yes, I think that, when water displaced by any thing is greater than it weight, it floats on water otherwise it sinks.

5. Find out from the other groups which things floats and which sank in the water?

Ans. A football, a piece of thermocol etc. float on water while a cricket ball, a spoon etc. sink.

After doing the experiment, write

1. The iron nail sank in the water but the katori floated. I think this happened because the weight of water displaced by the iron was less than it but the weight of water displaced by the katori was more than it.

2. The empty plastic bottle floated on water. The bottle filled with water sank because the weight of water displaced by the empty plastic bottle was more than its weight but the weight of bottle filled with water was more that that of the weight of watered displaced by it.

3. The aluminium foil floated when it was spread out. When pressed tightly into a ball it sank. This may have happened because the weight of aluminium foil is less than that of water displaced by it but the weight of aluminium ball is more than that of the water displaced by it.

6. Take some water in a glass. Put a lemon in it. Now keep putting salt in the water, half-a-spoon at a time. Were you able to float your lemon in water?

Ans. Yes, the lemon starts to float on water.

7. What do you think, the lemon floated in salty water because….

Ans. Because after adding salt, water because sticker.

8. Make groups of four friends. For the experiment you will need 4-5 glasses or bowls or bowls and the things listed in the table. Take some water in each glass. Now try to dissolve one thing in one glass. Observe that happens and note in the table.

Ans.

Things	Did it dissolve or not?	What happened after Keeping for 2 minutes?
1. Salt	Yes	Salt and water got mix together completely.
2. Soil	No	Soil settled down at the bottom of the glass.
3. Chalk powder	No	Chalk settled down at the bottom of the glass.
4. 1 Spoon milk	Yes	Milk and water got mixed together completely.
5. Oil	Yes	Oil floats on the surface of water.

9. Could you see the salt after it dissolved in water? If no, why?

Ans. No, because salt got dissolved completely into the water.

10. Does that mean that the water does not have salt? If it has, then where is the salt?

Ans. Of course, water contains sal. It is completely mixed up with water.

11. What difference did you see in water with salt and water with chalk powder after keeping for sometime?

Ans. Water and salt got mixed together completely while chalk powder settle down at the bottom of water.

12. Which of the two would you be able to separate from the water by straining with a cloth-salt or chalk powder?

Ans. We can separate chalk powder by straining with a cloth.

13. Do you think the oil dissolved in the water? Why do you think so?

Ans. I do not think so because oil is insoluble in water.

14. You also try to do the same and then which drop went ahead? Why did it slide faster?

Ans. The water drop went ahead. It happens because water does not stick to the tiffin box but the sugar and oil drop sticks.

15. One day Ayesha’s mother put some water to boil on the stove for making tea. She got busy with something and forget about it. When she remembered and came to check, she found only a few drops of water left in the pan.

Think where did the water go?

Ans. The water evaporated.

16. Why did Chittibabu and Chinnubabu keep their mango jelly in sun?

Ans. They did so to evaporated water from their mango jelly.

17. At your house, what things are made by drying in the sun?

Ans. Eatables like mango jelly (aam papad), papad, badis and potato chips are made by keeping in the sum.

18. You have washed you handkerchief and you want to dry it quickly. What all can you do?

Ans. For that, first the water form the handkerchief should be squeezed out properly and then it should be kept in the sun or pressed (by iron).

19. What things do you put in water to make tea? Which of these things dissolve in water?

Ans. To make tea, we add milk, tea leaves and sugar into the water. Out of these milk and sugar get dissolved.

20. You have been given some mishri pieces (lumps of sugar). Suggest some ways to dissolve them quickly.

Ans. To dissolve the mishri quickly. First it should be crushed to make powder of it. Then after adding it into water, the mixture should be stirred thoroughly. The mixture could also be heated over the flame to dissolve the mishri quickly

 

Question. Wet clothes are left in the sunlight to dry. What happens to all the water in the wet clothes after a while?
(a) All the water drips off.
(b) Some water drips off and some condenses.
(c) Some water drips off and some evaporates.
(d) Some water drips off and some gets absorbed into the clothes.

Answer : C

Question. Which of these containers has 20ml of water?

Answer : B

Question. Bindu's teacher asked a few students to perform an experiment described in the textbook. However, Bindu found that her results were different from what was described in the book. What should Bindu do?
(a) She should keep repeating the experiment till she gets the result reported in the textbook.
(b) She should change the observations so that she gets the result reported in the textbook
(c) She should use her friends' observations.
(d) She should report her observations the way they are.

Answer : D

Question. The set up shows an apparatus for filtration. This apparatus can be used for separating which of the following mixtures?

(a) salt and sugar
(b) sugar and water
(c) glucose and water
(d) saw dust and water

Answer : D

Question. A dry, empty glass is carefully inverted into a vessel of water without tilting. Which of these figures correctly shows the level of water in the inverted glass?

Answer : B

Question. See the flow chart on identification of states of matter given  below.
For a substance, the answer to both the questions below were YES.
Which of these could it be?.

(a) Ice cubes
(b) Water
(c) Air
(d) Honey

Answer : A

Question. Shyam took out a bottle of cold water from the fridge, wiped it dry and left it on the table. A few minutes later he found water droplets on the outside of the bottle. Which process leads to the formation of the droplets.
(a) Precipitation
(b) Evaporation
(c) Condensation
(d) Filtration

Answer : C

Question. Indu weighed a brinjal and a tomato. She then baked them in a hot oven for about 15 minutes, and weighed them again after that. How would their weight have changed, and why?
(a) INCREASED, because they absorb heat during baking.
(b) INCREASED, because they absorb water from the oven.
(c) DECREASED, because they lose water during baking.
(d) DECREASED, because a part of them burnt.

Answer : C

Question. A glass bottle is filled with hot water which is then emptied, and a balloon immediately fitted to its mouth. The bottle is then immersed in cold water. Which of these is likely to be the result after a few seconds?

Answer : B

Question. Ameena asked for a glass of water at her friend, Sushmas place. The glass was misty and had tiny droplets of water on it. Which of these could be the temperature of the water, if the room temperature was 30 degreeC?

(a) -4 degreeC
(b) 10 degreeC
(c) 30 degreeC
(d) 70 degreeC

Answer : B

Question. The figure shows soap bubbles. What is inside the soap bubbles? 

(a) soap
(b) air
(c) water
(d) nothing

Answer : B

Question. Study the given flowchart carefully. Which letter would BEST represent 'dry leaves'? 

(a) A
(b) B
(c) C
(d) D

Answer : C

Question. Sometimes, after a rain, a rainbow can be seen. Other than rain, what else is needed for the rainbow to form?
(a) Fog
(b) Clouds
(c) Snow
(d) Sunshine

Answer : D

Question. The science teacher at Sam's school has asked students to find out whether more salt dissolves in water at a higher temperature.  Which are the set of beakers that Sam must take in order to do the experiment correctly?

Answer : D

Question. Three vessels containing water as shown below are left undisturbed in the same place. After a few days, in which of these vessels will the water level be the lowest?

(a) P
(b) Q
(c) R
(d) It will be the same in all three vessels.

Answer : B