Skip main navigation
We use cookies to give you a better experience, if that’s ok you can close this message and carry on browsing. For more info read our cookies policy.
We use cookies to give you a better experience. Carry on browsing if you're happy with this, or read our cookies policy for more information.

Skip to 0 minutes and 5 secondsClouds, we see them everyday in the skies over our heads but did you know you could make your own, in your own home, in a bottle. You just need three things - some water, a bottle and some matches. First things first you need to put the water in the bottle . You can pretty much use any kind of plastic bottle but with one this size we found it work best if it is around about 3/4 full. Put the lid on and give it a little bit of a shake. This allows the air at the top to become saturated with water vapour.

Skip to 0 minutes and 32 secondsNow give it a squeeze, you're raising the pressure at the top of the bottle and the temperature, let it go and you're reducing the pressure and the temperature but nothing is happening. Well this is why we need the matches strike a match and pop it in the water. It soon goes out, you can't see any smoke particles in there, but now put the lid back on and give it a squeeze, as soon as you release, you'll see your cloud forming in the top of the bottle. So what's going on here?

Skip to 1 minute and 9 secondsWell initially not very much, not until we added the match because the match adds tiny smoke particles and you need those tiny particles - condensation nuclei - for the water droplets to form. You can't see the water vapour in the air initially, but give the bottle of squeeze and it raises the pressure and the temperature. Let it go, the pressure drops, that allows the water to cool and condense and it will form those tiny droplets, but only if you've got those condensation nuclei in there added by the smoke. They form tiny water vapour droplets and that is the clouds that we see every day over our heads

Cloud in a bottle

If you try this out for yourself at home, please be careful, particularly around the potential fire risk when using the matches. We recommend you complete the experiment well away from flammable materials, in a room with a high ceiling, or even better, do the experiment outside.

There’s a worksheet to accompany the video demonstration in the files section below.

Share this video:

This video is from the free online course:

Learn About Weather

University of Exeter

Get a taste of this course

Find out what this course is like by previewing some of the course steps before you join:

  • Why the sky is blue
    Why the sky is blue
    video

    Why is the sky blue? Why does the sky go red at sunrise and sunset? This Met Office video explains how colour wavelengths affect how we see the skies.

  • Introducing weather fronts
    Introducing weather fronts
    video

    Weather fronts are the boundaries between air masses. Watch Met Office meteorologist Alex Deakin demonstrate a front using a tank of coloured water.

  • How clouds form
    How clouds form
    video

    This Met Office video explores clouds including; how cloud droplets are formed from condensation nuclei and how much a cloud can weigh.

  • Five unusual rainbows
    Five unusual rainbows
    video

    Have you ever seen a full circle rainbow? Would you recognise a fire rainbow or a monochrome rainbow? Watch this Met Office video to find out more.

Contact FutureLearn for Support