Why does water stay cool in earthen clay pots?

Fri, 21 Feb 2003 13:54:47 +0000

Have you ever had a drink of cool refreshing water from a ‘matka’ or earthen clay pot placed outside? Surprisingly enough, the pots are exposed to blazing sunlight, yet the water within stays so cool. How is that possible?

This is because of a physical process known as evaporation. When a liquid changes to a gaseous (or vapour) state without boiling, it is known as evaporation.

A matka is made of mud and has many minute pores (extremely small holes). No matter how tightly you pack the mud, these pores remain. It is through these pores that the water, placed inside the matka, oozes out. Now, to evaporate, the water needs to absorb heat, which will change it to vapour.

Water Evaporation on Pitara Kids Network

Why does water stay cool in earthen clay pots?