Question

Why does a desert cooler cools better on a hot dry day? Every one is saying that it helps the water to evaporate, but which water?

Answer 1

this answer is in science book class 9 ch 1

hope this will help you

Answer 2

The particles of liquid in desert cooler absorb energy from the surrounding to regain the energy lost during evaporation. In summer this is fast. Hence desert cooler cool better in a hot dry day.