Chapter 8 Solutions — A Journey through States of Water

Let Us Enhance Our Learning

1. 1.
   Which of the following best describes condensation?

   • (i) The conversion of water into its vapour state.
   • (ii) The process of water changing from a liquid into gaseous state.
   • (iii) The formation of clouds from tiny water droplets.
   • (iv) The conversion of water vapour into its liquid state.
2. 2.
   Identify in which of the given processes, evaporation is very important—

   • (i) Colouring with
   • (a) crayons
   • (b) water colours
   • (c) acrylic colours
   • (d) pencil colours
   • (ii) Writing on paper with
   • (a) pencil
   • (b) ink pen
   • (c) ball point pen
3. 3.
   We see green coloured plastic grass at many places these days. Space around natural grass feels cooler than space around the plastic grass. Can you find out why?
4. 4.
   Give examples of liquids other than water that evaporate.
5. 5.
   Fans move air around, creating a cooling sensation. It might seem strange to use a fan to dry wet clothes since fans usually make things cooler, not warmer. Normally, when water evaporates, it requires heat, not cold air. What do you think about this?
6. 6.
   Usually, when sludge is removed from drains, it is left in heaps next to the drain for 3–4 days. Afterward, it is transported to a garden or a field where it can be used as manure. This approach reduces transportation cost of the sludge and enhances the safety of individuals handling it. Reflect upon it and explain how.
7. 7.
   Observe the activities in your house for a day. Identify the activities that involve evaporation. How does understanding the process of evaporation help us in our daily activities?
8. 8.
   How is water present in the solid state in nature?
9. 9.
   Reflect on the statement "Water is our responsibility before it is our right." Share your thoughts.
10. 10.
    The seat of a two-wheeler parked on a sunny day has become very hot. How can you cool it down?