Why evaporation is useful

Dry fish, salt and cool water from a clay pot.

Drying food

Evaporation is used to dry food. In Bangladesh, fish are dried in the sun to make shutki. Drying preserves food, because germs cannot grow without water.

Rice, chillies and lentils are also dried in the sun after harvest so they can be stored for months.

Making salt

Seawater is let into shallow salt pans. The Sun evaporates the water, leaving salt behind. Salt farmers rake up the salt crystals.

Salt farming is hard work in hot sun. The farmers flatten the clay floors of the pans so the salt can be scraped up cleanly.

Keeping cool

Water seeps slowly through a clay pot and evaporates from the outside. Evaporation takes heat away, so the water inside stays cool. People have used clay pots to cool water for thousands of years.

Clay pots work best in dry, breezy places. In very humid weather less water evaporates, so the water does not get as cool.

Drying clothes and roads

Evaporation dries clothes, roads and playgrounds after rain. It also helps make clouds – which bring rain back to us.

Black, tarred roads heat up quickly in the sun, so puddles on them dry faster than puddles on grass.

What I learnt

I can describe ways that evaporation is useful.
I know that evaporation cools things down.