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Cloud in a Jar

What are clouds made of? Learn about the science behind clouds as you make your own miniature cloud!

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  • What do you already know about clouds? 
  • How are clouds formed in the sky? If you’re not sure, check out this activity’s review section for some info on how clouds are made! 
  • Will you do this experiment on your own, with a partner or in small teams? 
  • What supplies will you need to make your own cloud? 
  • How can you make sure that you are safe while handing supplies like hot water? 


  • Start by (carefully!) pouring hot water into the jar. Swirl it around a bit to warm up the sides of the jar. 
  • Turn the lid upside down and place it on the top of the jar. Place a few ice cubes onto the lid and keep the lid on top of the jar for 20 seconds. 
  • Remove the lid then spray a bit of hairspray into the jar, then replace the lid as it was with the ice still on top. 
  • Watch your cloud form! 
  • When you see condensation (water droplets) forming in the jar, open the lid and release your cloud into the air!  


  • Were you able to make a cloud? 
  • How did your cloud in a jar mimic how clouds are made in nature? 
  • What happened when you released the clouds from the jars? 
  • In the air, clouds form when invisible water vapour condenses (turns into water droplets) in the air. These water droplets cling to tiny particles in the air, like dust or ash. When the water droplets condense and cling to particles, they form the clouds that we can see in the air.   
  • In this experiment, the cloud formed because when you added the warm water to the jar, some of it turned into invisible water vapour. The water vapour rose to the top of the jar where it met the cold air from the ice cubes. The water vapour then condensed – just like in nature, it needed something to condense to – but in this case, it condensed onto the hairspray! 
  • How does dirty air affect us? What should we do when the air quality is low? 
  • How can we check how clean the air is? 


Materials list is per individual, pair or small team.   

  • A jar with a lid 
  • 1/3 cup hot water 
  • Ice 
  • Hairspray 

Keep it Simple

  • Have everyone go through the steps of the experiment together before trying it. If it will help, draw each step on a piece of paper so that you have something to follow along with.  

Take it Further

  • Do you know of any other ways to make a cloud in a jar? Research some other techniques and see what you can try! What method makes the best cloud? Which method works the fastest?