Chapter 8: A Journey through States of Water
Comprehensive Exercise (Made for exam preparation)
Class 6 Science
Question 1: Choose the correct option (Multiple Choice Questions):
1. What is the process of conversion of water into water vapour called?
Answer: (B) Evaporation.
2. What is the solid state of water known as?
Answer: (C) Ice.
3. Under which of the following conditions will water evaporate the fastest?
Answer: (C) On a hot, sunny, and windy day.
4. What is the reason for the appearance of water droplets on the outer surface of a glass containing ice-cold water?
Answer: (C) Condensation of water vapour present in the air.
5. Water vapour rises up in the atmosphere because it is:
Answer: (B) Lighter than air.
Question 2: Fill in the blanks with the appropriate words:
- 1. Water can be observed in three different states in our daily life: solid, liquid, and gas.
- 2. When air moves higher above the Earth's surface, it becomes cooler.
- 3. In summers, a traditional clay pot called a Surahi is used to keep the water cold.
- 4. In the atmosphere, water droplets join together and generally form around dust particles to create clouds.
- 5. Water vapour is actually invisible, but the presence of tiny droplets of water in the steam makes it visible.
Question 3: State whether the following statements are True or False:
- 1. Ice and water are two forms (states) of the same substance.
Answer: True. - 2. Condensation is the process by which water converts into steam.
Answer: False (Condensation is the conversion of water vapour into its liquid state). - 3. Clothes dry slower on a windy day compared to a calm day.
Answer: False (With the increase in the movement of air, water evaporates faster). - 4. Water in the form of ice feels hard to touch, whereas liquid water flows.
Answer: True. - 5. Some water drops in clouds get so heavy that they start falling down as rain, hail, or snow.
Answer: True.
Question 4: Match the items in Column 'A' with the correct items in Column 'B':
| Column 'A' | Column 'B' |
|---|---|
| 1. Solid state of water | (a) Conversion of water vapour into liquid |
| 2. Evaporation | (b) Uses a layer of wet sand for cooling |
| 3. Condensation | (c) Ice |
| 4. Clouds | (d) Floating water droplets formed high in the sky |
| 5. Pot-in-pot cooler | (e) Conversion of water into steam |
Correct Matches:
- 1 → (c) Ice
- 2 → (e) Conversion of water into steam
- 3 → (a) Conversion of water vapour into liquid
- 4 → (d) Floating water droplets formed high in the sky
- 5 → (b) Uses a layer of wet sand for cooling
Question 5: Classification. Classify the following 5 phenomena into "Evaporation" and "Condensation":
Items: 1. Disappearance of water from puddles after rain, 2. Water droplets forming on the outer surface of a cold drink bottle, 3. Drying of wet clothes on a sunny day, 4. Formation of clouds in the sky, 5. Water sprinkled on a hot dosa pan turning into steam.
- Evaporation: 1. Disappearance of water from puddles after rain, 3. Drying of wet clothes on a sunny day, 5. Water sprinkled on a hot dosa pan turning into steam.
- Condensation: 2. Water droplets forming on the outer surface of a cold drink bottle, 4. Formation of clouds in the sky.
Question 6: Answer the following questions in one sentence:
1. What happens to the shape of an ice cube when it is transferred from one container to another?
Answer: The shape of the ice cube does not change because it is in a solid state.
2. What does a digital weighing balance show if we weigh a glass tumbler with cold water and ice over time?
Answer: The reading on the digital weighing balance increases because water vapour from the air condenses and collects on the outer surface of the tumbler.
3. Why do clothes dry faster in sunlight than in the shade?
Answer: Because water evaporates faster in the sunlight (heat) compared to the shade.
4. What is humidity?
Answer: The amount of water vapour present in the air is known as humidity.
5. How do clouds form in the sky?
Answer: When air moves higher, it cools down and the water vapour in it turns into tiny water droplets around dust particles, which float and form clouds.
Question 7: Give scientific reasons:
1. Reason: Water droplets appear on the outer surface of a glass tumbler containing ice-cold water.
Answer: Because the water vapour present in the surrounding air comes in contact with the cold surface of the glass tumbler and condenses into liquid water droplets.
2. Reason: We conclude that water is not seeping through the glass wall in the cold water tumbler activity.
Answer: Because if we take room temperature water in another identical tumbler, no water droplets appear on its outer surface, which proves that the water outside the cold tumbler comes from condensation, not seeping.
3. Reason: Clothes dry faster on a hot and windy day.
Answer: Because both the high temperature from the sun and the increased movement of air (wind) make the water evaporate from the clothes much faster.
4. Reason: Water vapour naturally rises up in the atmosphere.
Answer: Because water vapour is a gas that is lighter than air, and just like balloons containing lighter gases go up, water vapour also rises.
5. Reason: It rains when clouds get heavy.
Answer: Because inside the clouds, many tiny droplets join together to form bigger drops of water, and when these drops become too heavy to float in the air, they fall down as rain.
Question 8: Answer the following questions in short (2-3 sentences):
1. Define the terms Evaporation and Condensation.
Answer: The process of conversion of water into water vapour (steam) is called evaporation. The process of conversion of water vapour back into its liquid state is called condensation.
2. What are the three different states of water? Give one example of each.
Answer: The three states of water are solid, liquid, and gas. An example of the solid state is ice, the liquid state is the water we drink, and the gaseous state is water vapour or steam.
3. Explain the difference in behaviour between ice and liquid water when poured into different containers.
Answer: Ice is a solid, so it retains its fixed shape regardless of the container it is placed in. On the other hand, water is a liquid; it flows and takes the shape of the new container.
4. What happens when we sprinkle some water on a very hot pan?
Answer: The water sprinkled on the hot pan quickly evaporates and gets converted into steam. This steam is actually water vapour, which is invisible.
5. Describe how a Pot-in-pot cooler works.
Answer: A pot-in-pot cooler consists of a smaller pot placed inside a larger pot, with a layer of wet sand between them. As the water from the wet sand evaporates, it takes away the heat, keeping the things inside the smaller pot cool.