I’m always on the lookout for interesting, educational stuff I can do with my kids, preferably something that doesn’t involve a lot of mess. This cloud in a jar experiment is easy peasy and pretty cool!
You will need:
Very hot water
Cut off the narrow part of the balloon and make sure it can fit over the mouth of the jar.
Pour about 1/2 an inch of hot water into the jar. Light the match and, tilting the jar, capture some of the smoke. Discard the match and quickly cover the jar by stretching the balloon over the top.
Put pressure on the balloon with your fingers (make sure to secure it in place so it doesn’t slip off). Release. Do it several times to watch the cloud form and condense!
For a more impressive display, dim the lights and shine through the jar with a flashlight to see the swirling mist inside.
Explanation: putting pressure on the balloon increases pressure inside the jar, which in turn increases heat. Releasing the pressure makes the vapor from the hot water cool down and condense on the smoke particles – that’s how real clouds form, by condensing over particles floating in the air.
When you are done playing, take the balloon off and watch your cloud gently float upward out of the jar.