Evaporation

In dry air, water evaporates quickly and many molecules leave the container as vapor. But little vapor comes back in to form liquid, because dry air holds so little moisture that condensation rarely happens. In humid air, evaporation is slow, and the water evaporating from the surface of the container is balanced by fast condensation of the moisture in the air.

📖 In short

Evaporation is when a liquid turns into a gas. When you hang wet clothes in the sun and they dry, where does the water go? It evaporates and rises into the air as invisible vapor!

🤩 Did you know?

Evaporation is faster when the liquid gets hotter.
Some solids turn straight into gas without melting, like dry ice.
Water in an open glass slowly evaporates even if it doesn't boil.
The opposite of evaporation is condensation, when vapor turns back into water.

🔎 Find out more

🌟 Heat speeds it up

The hotter it is, the faster water evaporates. That's why clothes dry quickly in summer, and a rain puddle dries up a few hours after the sun comes out.

🔍 Wind helps

Wind carries vapor away from the water so more water evaporates quickly. That's why clothes dry faster on a sunny, breezy day.

💡 Evaporation cools

When you get out of water you feel cold, because the water on your skin evaporates and takes heat with it. That's how sweat cools your body in the heat, and how a clay jar keeps its water cool.

🎯 Evaporation and the water cycle

The sun heats the water in seas and rivers, which evaporates and rises into the sky, then cools into clouds and falls as rain. Salt doesn't evaporate with the water, which is why we get salt by evaporating seawater.

📸 More pictures

🧩 Test yourself

1 What happens to water when it evaporates?

2 When do clothes dry fastest?

3 Which picture shows “Evaporation”?