Ans:
(a) No
Oil does not dissolve in water. Instead of mixing, oil floats on top because they have different properties.
(b) Yes
View AnswerSugar dissolves in water, meaning it mixes well. When you stir sugar into water, it disappears and makes the water sweet!
(c) Yes
View AnswerSalt also dissolves in water. When you add salt to water and stir, it breaks down into tiny pieces and makes the water salty and clear.
(i) Ayesha saw that at first puri ____________ to the bottom of the pan; as puffed up, it started ____________ on the oil.
Ans: Ayesha saw that at first puri sank to the bottom of the pan; as it puffed up, it started floating on the oil.
When Ayesha first dropped the puri into the hot oil, it sank because it was heavy. But as it cooks, air gets inside it, making it lighter and allowing it to float.
(ii) When Ayesha put salt in the boiling water; eggs started ____________.
Ans: When Ayesha put salt in the boiling water, eggs started floating.
Adding salt to water makes the water denser. This means that objects like eggs can float instead of sinking!
Floating Egg Experiment
(iii) On ____________ sugar gets quickly dissolved in water.
Ans: On stirring, sugar gets quickly dissolved in water.
Stirring helps sugar mix better with water. It speeds up the process, making it dissolve faster.
(iv) Oil does not ____________ in water.
Oil does not dissolve in water.
This means that oil and water can’t mix together; they remain separate.
(v) The ____________ made a law that people could not make ____________ even for use at home.
The British made a law that people could not make salt even for use at home.
This law was unfair, as salt is essential for cooking, and it made life difficult for many people.
(vi) The ____________ can be used to make salt.
The seawater can be used to make salt.
Seawater contains a lot of salt. We can extract it to use for cooking and other purposes!
Sea Water is Salty
(vii) For making salt, water is allowed to dry in ____.
For making salt, water is allowed to dry in the sun.
When seawater is left out in the sun, the water evaporates, leaving behind salt.
(viii) Dead Sea is the _______ of all.
The Dead Sea is the saltiest of all.
The Dead Sea has a very high concentration of salt, making it much saltier than any ocean or sea!
Ans:
(i) A puffed-up puri will float in water.
Ans: True
Puffed-up puris are light and will float!
(ii) A steel plate sinks in water.
Ans: True
Steel is heavy, so it sinks in water.
(iii) A plastic bottle cap floats in water.
Ans: True
Plastic is lighter than water, so it floats.
(iv) The Dead Sea has the saltiest water of all seas.
Ans: True
The Dead Sea is known for its high salt concentration.
Floating in Dead Sea
(v) Oil can easily mix with water.
Ans: False
Oil and water do not mix; they stay separate.
(vi) Sugar and salt do not dissolve in water.
Ans: False
Both sugar and salt dissolve in water and give clear solution.
(vii) Salt is made from seawater.
Ans: True
We can obtain salt from seawater through evaporation.
(viii) Sugar and salt do not dissolve in hot water.
Ans: False
In fact, sugar and salt dissolve even faster in hot water!
(i) How would you separate
(a) Salt from water?
Ans:
Evaporation: Separating Salt and Water
(b) Chalk powder from water?
Ans:
(c) Mud from water?
Ans:
(ii) Name two factors that help the sugar dissolve in water.
Ans:
(iii) Does oil dissolve in water? Why?
Ans:
Oil & Water
(i) Why do puris float on oil while frying?
Ans:
(ii) Why does a soap case float in water while a cake of soap sinks?
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(iii) Why does an iron nail sink in water while an iron ship floats?
Ans: The density of nails (as of iron) is much larger than that of water. So it sinks easily.
(iv) What happens when salt is added to water in which eggs are boiled? Why?
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(v) Which handkerchief will dry faster: one kept in the sun or one kept in the shade? Why?
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(vi) Why do clothes dry faster on a sunny day than on a cloudy day?
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(vii) Look at the picture and write how salt can be obtained from seawater.
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(viii) Mahatma Gandhi was picking up salt in the picture. In which march (or) movement he did do it? Why did he undertake this march?
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(ix) In the given picture a person is floating on water in a lake. What is that lake called? How he can float on water? (or) Why do a person who cannot swim, will not drown in the Dead sea?
Ans:
(x) Ayesha put two drops each of groundnut oil, sugar solution, and water on a stainless steel plate. She tilted the plate and found that some of the drops slid down quickly while some lagged behind. Now answer the following questions.
Which drops slid down faster?
Ans:
(xi) Encircle the things that dissolve in water.
Sugar, Lemon juice, Oil, Fruit juice, Pepsi, Salt, Chalk powder, Mud, Ghee, Mishri (sugar lumps), and Milk.
Ans: Items that Dissolve: The following items dissolve in water:
(xii) A lemon sinks in a glass of plain water but floats on adding salt in the water. Why?
Ans:
(xiii) Suggest some ways to quickly dissolve sugar in water for making shakkarpara.
Ans:
34 videos|240 docs|41 tests
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1. What types of substances typically dissolve in water? |
2. How can I test if an object dissolves in water? |
3. Why do some objects not dissolve in water? |
4. Can you provide examples of insoluble substances? |
5. What is the importance of understanding which substances dissolve in water? |
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