How to make a cloud in a jar

How to make a cloud in a jar

Kitchen science is a great way to get kids thinking about how things work. Try this easy science experiment for kids and make your own cloud in a jar.

What you need:

  • 1 x glass jar with lid
  • 50ml boiled water from the kettle
  • aerosol can (eg. hairspray)
  • ice

Number of players:


Boil the kettle. Pour about 2cm of boiled water into the jar. Swirl the hot water in the jar so that it heats up the sides of the jar.

Turn the lid of the jar upside down and use it as a small container to put a few cubes of ice into. Rest it on top of the jar for a few seconds.

Take it off and quickly squirt in some hairspray (or whatever aerosol you're using). Put the lid, with the ice resting in it, back on top of the jar.

Watch the cloud form inside the jar. When it is fully formed, take the lid off and watch the cloud escape. 

Why is it so?

The atmosphere needs three ingredients to make a cloud:

1. warm, moist air

2. cooling (which causes the moisture to lift)

3. cloud condensation nuclei or CCN

(Cloud condensation nuclei = a very small particle that can float in the air to help water vapour condense into clouds. In Hawaii, for example, the most common CCN are sea salt aerosols, but CCN can also be dust, smoke, air pollution or volcanic fog.)

Here's what happened to make your cloud

By pouring hot water into a jar and trapping it, you created warm, moist air.  As the warm air inside the jar rose, it was then cooled by the ice on top of the jar.

When the water vapour cooled, it wanted to turn back into liquid, but it needed to condense onto a surface. The aerosol provided cloud condensation nuclei: a surface for the water vapour to condense into tiny cloud droplets.

The cloud swirled inside the jar due to the circulation of warm air rising and cold air sinking.


  • Thanks to our sister company Kidspot Australia for creating the instructional video.

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