Question

Why do people sprinkle water on a roof during a hot summer day?

Answer 1

Latent heat of vaporization:

Latent heat of vaporisation is defined as the heat required to change one mole of liquid at its boiling point under standard atmospheric pressure.

It is expressed as kg/mol or kJ/kg

• When we sprinkle water on the roof on a hot summer day it requires latent heat of vaporization to change the state from liquid to vapor.
• It vaporizes by utilizing a large amount of latent heat from the roof or ground and surrounding air.
• Hence the roof becomes cooler as it losses its heat to water.