A Journey Through States of Water — Mastery

Q1. An ice cube placed in a cup and left on a table gradually gets converted into water. What does this observation directly show?

• A. Ice and water are different substances
• B. Water freezes only inside a freezer
• C. Ice cannot exist outside a freezer
• D. Ice and water are two states of the same substance

Q2. Aavi puts water in the freezer of a refrigerator. After a few hours she finds ice. This shows that

• A. Some new substance has been added to the water
• B. The freezer destroys water
• C. Water has been converted into its solid state, ice
• D. Ice is heavier than water

Q3. After a mopped floor in a classroom dries up by itself in a few minutes, the water from the floor has

• A. Soaked into the floor permanently
• B. Frozen to a thin ice film
• C. Disappeared because no water was there to start with
• D. Evaporated into the air as water vapour

Q4. Which of the following statements about evaporation is correct?

• A. Evaporation takes place continuously, even at room temperature
• B. Evaporation happens only when water is heated to boiling
• C. Evaporation only takes place inside closed containers
• D. Evaporation needs ice to be present

Q5. Why is the steam rising from a pan of boiling water visible, even though water vapour itself is invisible?

• A. Steam is a different substance from water vapour
• B. Steam contains tiny water droplets along with water vapour, and the droplets are visible
• C. Steam is hot, and heat is visible
• D. Steam contains smoke from the pan

Q6. Atmospheric Water Generator (AWG) machines collect drinkable water from humid air. They do this mainly by

• A. Heating the air strongly so that water comes out
• B. Burning the air to release water
• C. Adding salt to the air
• D. Cooling the air so that the water vapour in it condenses on a cold surface

Q7. Water is boiled in a half-filled utensil and covered with a steel plate. Some water drops accumulate on the inner side of the plate. The drops come from

• A. Steel particles dropping into the water
• B. Air leaking into the utensil from the room
• C. Water vapour from the boiling water condensing on the cool inner surface of the plate
• D. Salt added to the water rising up

Q8. When 200 mL of water is poured from a measuring cylinder into a wide tray, what changes and what stays the same?

• A. Shape changes but volume remains the same
• B. Both shape and volume change
• C. Volume changes but shape remains the same
• D. Both shape and volume remain the same

Q9. We can smell food being cooked in the kitchen even when we are in a different room. The best reason is that

• A. The cook calls us to smell the food
• B. Sound from the kitchen carries the smell
• C. Smell, carried by gases, spreads through the air to reach our nose
• D. Solid bits of food fly to our nose

Q10. Water and many other substances can change their state by

• A. Adding salt only
• B. Stirring with a spoon
• C. Keeping them inside a dark cupboard
• D. Heating or cooling

Q11. In Activity 8.6, the diagram has three boxes labelled A (Solid), B and C, and four arrows labelled 1, 2, 3, 4. Arrow 1 between A and B is labelled 'Melts'. What is the best label for box B and box C?

• A. B = Liquid, C = Gas
• B. B = Gas, C = Liquid
• C. B = Solid, C = Liquid
• D. B = Liquid, C = Solid

Q12. When ice is taken out of a freezer and kept on the kitchen counter, what change is observed in it after some time?

• A. It evaporates into vapour directly without becoming water
• B. It turns into another gas
• C. It becomes harder than before
• D. It melts and is converted into water

Q13. If you want to dry wet clothes on a rainy day inside a small room, which step best helps them dry faster?

• A. Close all windows and doors tightly
• B. Pile the wet clothes one over another
• C. Spread the clothes wide and switch on a fan so air moves over them
• D. Sprinkle more water on the clothes

Q14. Two equal amounts of water are kept in identical open glasses, one on a hot summer afternoon and the other on a cold winter morning, both in the shade. After two hours

• A. The glass on the hot summer afternoon will have lost more water due to faster evaporation
• B. Both glasses will lose exactly the same amount of water
• C. The glass on the cold winter morning will have lost more water
• D. Both glasses will gain water

Q15. Why is it difficult to feel cool simply by sweating on a humid coastal day, even when the temperature is the same as a dry inland day?

• A. Sweat is different at the coast
• B. Coastal air is hotter than dry air at the same temperature
• C. Salt in the air stops sweat
• D. High humidity slows the evaporation of sweat, so the cooling effect is small

Q16. In many Indian homes, a surahi (a unique clay pot) is used in summer to keep drinking water

• A. Hot, so it kills germs
• B. Sweet, by adding sugar through the wall
• C. Heavy, by absorbing minerals
• D. Cool, by allowing water to seep and evaporate from its surface

Q17. Which two processes act together to give a matka its cooling effect on stored water?

• A. Heating of the water and condensation on the outside
• B. Freezing of the water and melting again
• C. Evaporation only; nothing else
• D. Seepage of water through the porous wall, followed by evaporation of that water from the outer surface

Q18. When we rub hand sanitiser on our hands, we feel a slight cooling on the skin because

• A. Sanitiser is naturally very cold
• B. Sanitiser pulls in cold air from outside
• C. Sanitiser freezes on our hand briefly
• D. Sanitiser evaporates, and evaporation has a cooling effect

Q19. Tiny water droplets that float in the air after condensation around dust particles are seen by us as

• A. Clouds
• B. Lightning
• C. Snowfields
• D. Rivers

Q20. Air containing water vapour rises to higher levels in the atmosphere. The 'Do you know?' box gives the reason as

• A. Water vapour is heavier than air
• B. Wind always blows water vapour upwards
• C. Air gets hotter at higher levels
• D. Water vapour is lighter than air, just like gas balloons containing lighter gases go up

Q21. The falling water drops from clouds may sometimes also fall as hail or snow

• A. Under special conditions in the atmosphere
• B. Only inside a freezer
• C. Whenever wind is strong, regardless of temperature
• D. Whenever there is sunshine

Q22. In the atmosphere, the role of dust particles in cloud formation is best described as

• A. They warm the air so that vapour rises
• B. They release water from inside themselves
• C. They provide surfaces around which water vapour can condense into tiny droplets
• D. They block the Sun so that condensation can begin

Q23. Reflecting on the statement 'Water is our responsibility before it is our right', which classroom action is the most effective for a Class 6 student?

• A. Stop drinking water during school hours to save it
• B. Wash the school bus daily with extra water
• C. Believe water will always be available because the water cycle never stops
• D. Avoid wasting water while drinking and washing, and check leaking taps in the school

Q24. According to the chapter, most of the water on Earth is

• A. Locked inside rocks and not part of the water cycle
• B. Stored as ice at the poles only
• C. In the oceans, and cannot be used directly by plants, animals and humans
• D. Already inside our bodies

Q25. In Activity 8.11 (Fig 8.9, label the water cycle), which of the following sets of words are all valid parts of the water cycle to use as labels?

• A. Cloud, Lake, Ocean, River, Groundwater, Evaporation, Condensation, Rain, Snow
• B. Cloud, Mobile phone, Ocean, Train
• C. Lake, Volcano, Computer, Ocean
• D. Rain, Helicopter, Train, Forest fire

Q26. A Class 6 teacher fills a tumbler with ice and water and asks: 'Predict what will happen on the outer surface in 30 minutes.' This step is best described as

• A. Asking students to remember a definition
• B. Telling students the correct answer first
• C. A predict-observe-explain step that activates students' thinking before the activity
• D. An assessment for grading

Q27. A Class 6 student says, 'Ice and water must be different substances because ice is hard and water flows.' Which is the most effective strategy for the teacher to address this misconception?

• A. Tell the student they are wrong and move on
• B. Read out the textbook definition of 'state' to the class
• C. Ignore the comment, since the syllabus does not allow time for it
• D. Place an ice cube on a table and let students observe it slowly melt into water of the same volume

Q28. Which of the following assessment ideas best matches the 'Learning further' suggestion in the chapter for the water cycle?

• A. Students enact the stages of the water cycle through a role-play activity in the school assembly
• B. Students write a 1000-word essay on rainfall in India
• C. Students take a written test on water vapour formulas only
• D. Students sit quietly and watch a teacher demonstrate the cycle once

Q29. (From 'Let us enhance our learning', Q1) Which of the following BEST describes condensation?

• A. The conversion of water into its vapour state
• B. The process of water changing from a liquid into a gaseous state
• C. The formation of clouds from tiny water droplets
• D. The conversion of water vapour into its liquid state

Q30. (From 'Let us enhance our learning', Q2) In which of the following processes is evaporation very important?

• A. Crushing stones with a heavy hammer
• B. Lifting a metal sheet with a magnet
• C. Pouring honey from a jar
• D. Colouring with water colours, and writing on paper with an ink pen