Think and find out :

1.  Ayesha put a puffed puri in a bowl of water, would it sink or float.
The puri will float.

2.  You put a steel plate on water. Would it sink or float. What would happen to a spoon.
If I put the steel plate on water it would float, the spoon would sink.

3.  Would the cap of a plastic bottle sink or float on water.
The cap of the plastic bottles would float on water.

4.  Have you seen that some thing float on water while others sink. Think how this happens!
Yes, I observed that certain things float on water while others, sink, everything displaced water is more than the weight of a thing, then the thing floats, otherwise it sinks in water.

5.  Do this experiment in groups of your friends. Each group will need a big pot filled with water and the things listed in the table. Put each thing one – by –one in water and observe.

Ans :

6.  Find out the other groups which things floated and which sank in the water .
A ball, A Styrofoam ball, etc. can float n water. An iron nail, a key, etc. will sink in water.

7.  After doing the experiment, fill in the blanks.

i) The iron nail ____________ in water but the katori __________ I think this happened because_____________ .

ii) The empty plastic bottle ___________ on water. The bottle filled with water __________ because ____________ .

iii) The Aluminium foil __________ when it was spread out. When pressed tightly into a ball it __________ this may have happened because____________ .

Answers :

i) The iron nail sank in water but katori floated  . I think this happened because iron nail could displace less amount of water than what was displayed by the katori .

ii) The empty plastic bottle floated. The bottle filled with water sink  because the filled bottle could displace less amount of water compared to its weight .

iii) The Aluminium foil floated when it was spread out. When pressed lightly into a ball it sank. This may have happened because Aluminium foil spread out could displace more water compared to its weight .

i) 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.
Yes, the lemon started to float on water.

ii) What do you think, the lemon floated in salty water because __________ .
Ans: After adding salt, the water became thicker and thus, the lemon started floating.

9.  What dissolved, What did not.

i) Suggest some ways to Hamid for quickly dissolving sugar.
Ans: Hamid should follow any of these methods:
a) Stir the mixture thoroughly.
b) Warm the mixture over a flame.

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

Things Did it dissolve or not What happened after keeping for 2 minutes
1. Salt
2. Soil
3. Chalk powder
4. Spoon milk
5. Oil

Ans :

Things Did it dissolve or not What happened after keeping for 2 minutes
1. Salt Yes Salt and water got mixed together completely. Water remained transparent
2. Soil No Soil settled down at the bottom. Water became muddy.
3. Chalk powder No Chalk powder settled down at the bottom. Water became whitish.
4. Spoon milk Yes Milk and water got mixed completely. Water became whitish.
5. Oil No Oil floats on the surface of water.

11.  Could see the salt after it dissolved in water. If no, why.
Ans :
Salt cannot be seem after it dissolves in water. This is because the salt is completely soluble in water.

12.  Does that mean that now the water does not have salt . if it has, then where is the salt.
Ans :
No , its does not mean that the water does not have salt. The salt is dissolved in water.

13.  What difference did you see –in the water with salt, and the water with chalk powder – after keeping for sometime .
Ans :
Salt mix completely with water, while chalk powder settled down at bottom.

14.  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 from water , by straining with a cloth.

15.  Do you think the all oil got dissolved in the water . why do you think so.
Ans :
I think that the oil did not dissolved in water . oil floating on water surface made me to think so.

16.  You also try do the same and then tell which drop went ahead . why did it slide faster .
Ans :
The drop of water went ahead slide faster. Drops of oil or sugar syrup stick to the tiffin box.

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

i) Think where did the water go.
Ans : The water evaporated and turned into vapour.

ii) Why did Chittibabu and Chinnababu keep their mango jelly in the sun.
Ans : They kept their mango jelly in the sun so that the water from the jelly could evaporate.

iii) At your house , what things are made by drying in the sun.
Ans :  Following items are made in my house by drying in the sun : Potato chips, papad, pickles, berries, Sabudana papad.

18.  You have washed your handkerchief and you want to dry it quickly. What all can you do.
Ans :
I will squeeze the water out of the handkerchief . Then I will spread the handkerchief on a clothes line , in the sun . I can also use a hot electric iron to dry the handkerchief.

19.  What all things do you put in water to make tea . which of those things dissolved in water .
Ans :
For making tea , I put sugar , milk and tea leaves in water . sugar and milk dissolve in water.

20.  You have been given some mishri pieces (lumps and sugar). Suggest some ways to dissolve them quickly.
Ans : Follow these steps to dissolve mishri pieces quickly :
i) Crush the mishri pieces in fine powder.
ii) Put it into water and stir thoroughly.
iii) You can also warm the mixture on the flame.

  Think and find out :

1) A lemon sinks in glass of plain water but floats on adding salt in the water. Why.
Ans :
A lemon sinks in a glass of plain water but floats on adding salt in the water because water become thicker (sense) on adding salt.

2) Why does a person floats in died sea even after he does not know how to swim.
Ans :
A person floats in dead sea even after he dies does not know how to swim because dead sea is the saltiest of all .

3) Suggest some ways to quickly dissolve in sugar water for making shakkarpara .
Following are the two ways to quickly dissolve sugar in water for making Shakkarpara:
i) Stir the mixture of sugar and water thoroughly.
ii) Warm the mixture over flame.

4) State the mixture of sugar and water called.
A mixture in which a substance has fully dissolved in water is called a solution. And the substances is said to be soluble. An example of this type of mixture is sugar in water. Here the dissolves fully to give a clear solution.

5) Do you think that the oil gets dissolved in water why do you think so.
Ans :
No, the oil does not get dissolved in water oil always floats on water this happens because water molecules are more attracted to each other than oil molecules.

6) How the salt is made.
Ans :
The sea water is collected in shallow beds dug in sand.Water is allowed to dry in the sun. Salt remains on the ground after the water is dried.

  Fill in the blanks :

1.  For making salt water is allowed to dry in ___________.

2.  Dead seas is the _____________of all.

3.  Common salt is ________in water while chalk powder does not dissolve in water .

4.  Iron nail sinks in water but the katori______________ .

Answers :
1.  Sun                        2.  Saltiest                   3.  Soluble                     4.  Floats .

  Match the columns :

                        A                         B
Oil and water Floats on sugarcane juice
Piece of ice Sinks in water
Empty plastic bottle Do not mix
Bottle full of water Floats on water