Fans move air around, creating a cooling sensation. Class 6

Fans move air around, creating a cooling sensation. Class 6

Question 1.

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? Class 6

Answer:

We can use fan to dry wet clothes, because it increases the movement of air around the wet clothes. Hence, increases the rate of evaporation. So, more the evaporation, faster the clothes dry.

Question 2.

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. Class 6

Answer:

The sludge taken out from drain contains lot of liquid wastes which increases its mass. More the mass to be transported, more will be the transportation cost. Hence, it is allowed to dry under the Sun. The liquid gets evaporated and then the reduced mass of dried sludge is transported. In this way cost of transportation is reduced.

Also, harmful microorganisms or germs survive more in wet waste. As the sludge dries up, health risks of handling it is also reduced.