Class 6 Science Chapter 8 Extra Questions and Answers – A Journey Through States of Water
Class 6 Science Chapter 8 Extra Questions and Answers for “A Journey Through States of Water” (based on NCERT textbook Curiosity).
EXTRA IMPORTANT QUESTIONS WITH ANSWERS – Chapter 8 – A Journey Through States of Water
This includes All types of Questions normally asked in school exams, tests, and NCERT exercises.
Very Short Answer Type Questions (1 Mark)
Q1. What are the three states of water?
Answer: Solid (ice), liquid (water) and gas (water vapour).
Q2. What is the process by which water changes into vapour?
Answer: Evaporation.
Q3. What is the process by which water vapour changes into water?
Answer: Condensation.
Q4. Name the process of converting a solid into a liquid.
Answer: Melting.
Q5. Name the process of converting a liquid into a solid.
Answer: Freezing.
Q6. Why does ice feel hard?
Answer: Because ice is the solid state of water and has a fixed shape.
Q7. Why can we not hold water like ice?
Answer: Water is a liquid and flows; it does not have a fixed shape.
Q8. Why are dew drops seen in the morning?
Answer: Because water vapour condenses on cool surfaces in the morning.
Q9. What is humidity?
Answer: The amount of water vapour present in the air.
Q10. What is the state of water present in the air?
Answer: Water vapour (gaseous state).
Short Answer Type Questions (2 Marks)
Q11. Why do water droplets appear on the outer surface of a cold glass?
Answer: Water vapour present in the air condenses when it touches the cold surface of the glass.
Q12. Why does water disappear from puddles?
Answer: Water evaporates into water vapour due to heat from the surroundings.
Q13. Why does a steel plate not allow water to seep through?
Answer: Steel is non-porous and does not absorb or allow water to pass through.
Q14. Give two examples of evaporation in daily life.
Answer:
- Drying of wet clothes.
- Drying of mopped floor.
Q15. What happens to the shape of ice when moved to another container?
Answer: Ice keeps its own shape; it does not change according to the container.
Q16. Why does water take the shape of the container?
Answer: Because water is a liquid and does not have a fixed shape.
Q17. Why does water in an earthen pot feel cool?
Answer: Water seeps out through tiny pores and evaporates, causing cooling.
Q18. What happens when steam touches a cold surface?
Answer: It condenses to form water droplets.
Long Answer Type Questions (3–4 Marks)
Q19. Explain how water changes from one state to another.
Answer:
Water changes its state when heated or cooled.
• Ice melts into water when heated (melting).
• Heating water changes it into water vapour (evaporation).
• Cooling water vapour forms water (condensation).
• Cooling water changes it into ice (freezing).
Thus, heat causes melting and evaporation, while cooling causes condensation and freezing.
Q20. Describe the water cycle.
Answer:
The water cycle is the continuous movement of water from the Earth’s surface to the atmosphere and back.
- Water evaporates from oceans, lakes and rivers.
- Water vapour rises, cools and condenses to form clouds.
- Clouds produce rain, hail or snow (precipitation).
- Water returns to oceans through rivers and groundwater.
This cycle repeats continuously.
Q21. Explain why clothes dry faster on a sunny or windy day.
Answer:
On a sunny day, heat increases evaporation.
On a windy day, moving air carries away water vapour faster.
Both conditions increase evaporation, drying clothes quickly.
Q22. Why does evaporation cause cooling?
Answer:
During evaporation, water absorbs heat from its surroundings to change into vapour.
This removal of heat produces a cooling effect, as seen in earthen pots, sweating and hand sanitiser.
Higher Order Thinking Questions (HOTs)
Q23. Why does hand sanitiser feel cold when applied?
Answer:
Sanitiser contains alcohol, which evaporates quickly by absorbing heat from the skin, creating a cooling effect.
Q24. Why do clouds form at high altitudes?
Answer:
At high altitudes, temperature is low. Water vapour cools and condenses into tiny droplets, forming clouds.
Q25. Why does water vapour rise up in the atmosphere?
Answer:
Water vapour is lighter than air; therefore, it rises upward.
Q26. Why do we smell food from the kitchen even when we are far away?
Answer:
Water vapour and food vapour spread through the air as gases and travel to our nose.
Q27. Why does water evaporate faster from a plate than from a bottle cap?
Answer:
A plate has a larger exposed surface area, increasing the speed of evaporation.
Activity-Based Questions (With Answers)
Q28. In Activity 8.2, water on a steel plate disappears without seeping. What does it prove?
Answer:
It proves that water evaporates instead of seeping through the steel surface.
Q29. In Activity 8.4, the mass of the tumbler increases. Why?
Answer:
Condensed water droplets add extra mass to the tumbler.
Q30. Why is marking the water level important in Activity 8.4?
Answer:
To show that water inside the glass does not leak out; the water outside comes from condensation.
Application-Based Questions
Q31. Why do we feel cool after sweating under a fan?
Answer:
Wind increases evaporation of sweat, removing heat and cooling the body.
Q32. Why is plastic grass hotter than natural grass?
Answer:
Plastic grass does not allow evaporation. Natural grass contains water, and evaporation cools the surroundings.
Q33. Why is water shortage increasing?
Answer:
Population is rising, more water is used and water bodies are polluted, making less water fit for use.
Q34. Why is evaporation slower on a rainy day?
Answer:
Humidity is high, so air already contains a lot of water vapour, slowing down evaporation.
Differentiation Questions
Q35. Differentiate between evaporation and boiling.
Answer:
Evaporation:
• Happens at all temperatures.
• Happens only at the surface.
Boiling:
• Happens at a fixed temperature.
• Happens throughout the liquid.
Q36. Differentiate between steam and water vapour.
Answer:
Steam:
• Visible because it contains tiny water droplets.
Water vapour:
• Invisible gas.
Diagram/Reasoning-Based Questions
Q37. Why does ice float on water?
Answer:
Ice is less dense than water.
Q38. Why does coconut oil freeze in winter?
Answer:
Low temperature causes the liquid oil to cool and freeze into solid.
Extra NCERT Value-Based Questions
Q39. What habits should we follow to save water?
Answer:
Close taps properly, reuse water where possible, avoid wasting water while bathing, keep water bodies clean.
Q40. Why must we keep our water bodies pollution-free?
Answer:
Polluted water harms humans, animals and plants.
Purifying polluted water requires more energy and cost.