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प्रश्न
Could you see the salt after it dissolved in water? If no, why?
उत्तर
Salt cannot be seen after it dissolves in water. This is because the salt is completely soluble in water.
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संबंधित प्रश्न
Ayesha put a puffed puri in a bowl of water. Would it sink or float?
Have you seen that something floats on water while others sink?
Make groups 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 it in the table.
| Things | Did it dissolve or not? | What happened after keeping for 2 minutes? |
| 1. Salt | ______ | ______ |
| 2. Soil | ______ | ______ |
| 3. Chalk powder | ______ | ______ |
| 4. 1 spoon milk | ______ | ______ |
| 5. Oil | ______ | ______ |
Does that mean that now the water does not have salt? If it has, then where is the salt?
What difference did you see - in the water with salt, and
the water with chalk powder - after keeping for some time?
Do you think the oil got dissolved in the water? Why do you think so?
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 very little water left in the pan.
Think where did the water go?
You have been given some mishri pieces (lumps of sugar). Suggest some ways to dissolve them quickly.
Find out from the other groups which things floated and which sank in the water?
After doing the experiment, fill in the blanks.
The aluminium foil ______ when it was spread out. When pressed tightly into a ball it ______. This may have happened because ______
On Sunday Ayesha’s cousin, brother Hamid came to her house to play. As soon as he came he asked his aunt to make his favourite shakkarpara (a sweet dish). Ammi said, “Let me come back from the market, then I will make some for you. Why don’t you help me? Take two glasses of water and put a bowl of sugar in it. Mix it till it dissolves.” Hamid thought, “Let me finish this work fast. Then I will watch TV”.
Suggest some ways to Hamid for quickly dissolving sugar.
