How are Clouds Formed?

Background Knowledge

Kindergarteners have already explored how rain clouds work.  They know that water is heated and evaporated from the sea, lakes, etc. As the water evaporates and forms into a cloud, it begins to cool down and condense.  When the cloud gets too full of water, the water falls in the form of rain. However, is this all that is needed for a cloud to form?

Question to Explore

Does a cloud need dust to form?


  • Mason jar with lid
  • hot water (can be heated in the microwave or in a tea kettle)
  • ice cubes
  • hairspray (to represent the dust)


  1. Begin by making a prediction. Will we be able to see the cloud form in the mason jar with or without the hairspray (dust?) or both?
  2. Fill a mason jar 3/4 of the way with hot (not boiling) water.
  3. Place the lid upside down on top of the jar and put a few ice cubes on the lid. This represents the hot air (from the hot water) rising and meeting with cold air in the atmosphere (the ice).
  4. After about a minute, take the lid off and see what you observe.
  5. With the lid and ice cubes handy, spray the inside of the jar with hairspray and quickly place the lid back on top upside down.  If you removed your ice cubes, place them back on top of the lid.
  6. Wait a minute and then remove the lid.  What do you observe?
  7. Make a claim. Why do you think this happened?



Students concluded that the cloud formed in the jar with the hairspray (dust), hot water, and ice on top, but did not form without hairspray (dust).

Here is a graphic organizer I created for students to record their observations:

Cloud in a jar