Evaporation

water cycle · temperature · weather · science

Molecules escape upward. When water gets warm enough, tiny molecules at the surface absorb energy and zoom off into the air as an invisible gas. The warmer it is, the faster they escape.

It makes things colder. When molecules leave a puddle or your wet skin, they carry heat energy with them. This is called evaporative cooling, and it's why sweating helps cool you down.

Humidity slows it down. If the air around water is already very humid (full of water vapor), fewer molecules can escape because there's nowhere for them to go. That's why wet clothes dry slower on humid days.

Part of Earth's water cycle. Evaporation from oceans, lakes, and rivers sends trillions of gallons of water into the atmosphere every day, where it eventually forms clouds and rain.

Energy does the work. Molecules need enough energy (usually from heat) to break free from the liquid and become gas. Without enough energy, they stay put.