Which factor is usually essential for the filtration?
(i) Apparatus size (ii) Presence of air
(iii) Pore size (iv) Temperature of the
mixture
Which of the following substances are commonly separated
using the churning method?
(i) Oil from water (ii) Sand from water
(iii) Cream from milk (iv) Oxygen from air
What purpose does handpicking serve in the process of
separation?
(i) Filtration (ii) Sorting
(iii) Evaporation (iv) Decantation
The seat of a two-wheeler parked on a sunny day has become
very hot. How can you cool it down?
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?
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