Reflect on the statement “Water is our responsibility before
it is our right.” Share your thoughts.
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?
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.
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?
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?
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
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.