A Journey Through States of Water — Quiz

Q1. Priya pours equal amounts of water into a small bottle cap and into a wide steel plate, side by side. Water in the plate evaporates faster mainly because

• A. The plate is made of steel and steel attracts water vapour
• B. The plate has a larger area of water exposed to the air
• C. The plate is heavier than the bottle cap
• D. The bottle cap holds water more tightly

Q2. Why do wet clothes hung in the courtyard generally dry faster on a windy day than on a calm day?

• A. The wind heats the clothes
• B. The wind increases the movement of air, so water evaporates faster
• C. Wind adds extra moisture to the clothes
• D. Wind lowers the humidity in the clothes only

Q3. Ravi notices that on a rainy day, clothes hung outside take much longer to dry. The best reason is

• A. The air on a rainy day is colder, which always stops evaporation
• B. The amount of water vapour in the air is already high (more humidity), so water evaporates slowly
• C. Clouds absorb the clothes' moisture
• D. Rain water mixes with the clothes' water and makes them heavier

Q4. Water droplets appear on the outer surface of a glass tumbler containing cold water and ice cubes. The droplets come from

• A. Water seeping out through the wall of the tumbler
• B. Melted ice that has come out of the tumbler
• C. Water vapour in the air condensing on the cold outer surface
• D. A leak at the bottom of the tumbler

Q5. In Activity 8.4, a glass tumbler half-filled with water and ice is covered and kept on a digital weighing balance for 30 minutes. What is observed?

• A. The mass on the balance decreases
• B. The mass on the balance increases
• C. The mass remains exactly the same
• D. The water turns into a different substance

Q6. Why do we feel cool when we sit under a fan after running in the playground?

• A. The fan blows out cold air at room temperature
• B. The wind from the fan helps the sweat on our skin evaporate, which cools our body
• C. The fan changes the air into water vapour
• D. The fan increases the humidity around our body

Q7. In summer, sprinkling water on the floor or roof helps cool the room because

• A. Water on the floor blocks sunlight
• B. Evaporation of the sprinkled water produces a cooling effect on the surface
• C. Water absorbs warm air from outside
• D. Water reflects heat back to the sky directly

Q8. Air containing water vapour rises in the atmosphere. As it moves higher, its temperature becomes

• A. Hotter and hotter
• B. Unchanged
• C. Cooler and cooler
• D. First hotter, then cooler

Q9. In Activity 8.10, a small burnt piece of newspaper is added to a closed plastic bottle containing some water. On squeezing and releasing the bottle, some haziness (clouds) is seen above the water. The burnt newspaper helps because it

• A. Heats the water and makes it evaporate
• B. Releases tiny dust particles around which water vapour can condense
• C. Adds extra water vapour to the bottle
• D. Lowers the pressure inside the bottle by itself

Q10. Which everyday example, besides water, best illustrates melting (solid to liquid)?

• A. A candle wax becoming liquid on heating, and turning solid again on cooling
• B. Wet clothes drying in the sun
• C. Dew drops forming on plants
• D. A balloon filled with gas going up in air

Q11. To convert ice into water and then water into water vapour, what must be done?

• A. Heat must be supplied at each step
• B. The ice must be cooled further
• C. Some other substance must be added
• D. The container must be sealed tightly

Q12. In the water cycle, where does most of the water that evaporates into the atmosphere come from?

• A. The oceans and the Earth's surface
• B. Plants and animals only
• C. Underground caves
• D. Volcanoes and hot springs

Q13. Why is it important to use water wisely, even though Earth has so much water?

• A. Earth is losing water to space rapidly
• B. Only a small portion of Earth's water is fit for use by plants, animals and humans; most water is in oceans and cannot be used directly
• C. All fresh water has already been frozen at the poles
• D. Water cannot be cleaned at all once it is used

Q14. Hand sanitiser disappears from our hands as we rub them together. The disappearance is best explained as

• A. Melting of the sanitiser into the skin
• B. Evaporation of the sanitiser into water vapour and other vapours
• C. Freezing of the sanitiser on the hand
• D. Condensation on the hand

Q15. When water is poured from a tall narrow glass into a wide flat bowl, the water

• A. Keeps its tall narrow shape
• B. Changes its shape to that of the bowl, but its volume remains the same
• C. Loses some volume because of the change of shape
• D. Becomes ice because of the change in container