Skip to main content

← Summer Solo-Science

Rainy-day bonusReleases June 22

Bonus: cloud in a jar

A rainy-day quickie — make a real cloud appear inside a jar and watch how clouds actually form.

For you to do

You'll put warm water and a tiny bit of 'dust' (smoke or a spritz) in a jar, then cap it with ice on top. A cloud forms in the middle as the warm air rises and cools.

Grown-up help

Ask a grown-up to pour the hot water and to do the match/hairspray step. You set up the jar and watch.

Make a cloud

  1. A grown-up pours a little hot water into the jar and swirls it.
  2. A grown-up adds a tiny puff of smoke (a blown-out match) or a quick spritz of hairspray, then you cap the jar.
  3. Put ice cubes on the lid. Watch the cloud swirl inside, then lift the lid to let it escape.

What's happening

Warm, wet air rises and meets the cold lid; the water vapor cools and sticks to the tiny dust bits, forming a visible cloud — a tiny weather **system**. Try changing one **variable** (more ice, warmer water) and record your **observation** of how the cloud changes.