Rainstorm in a Glass Experiment

This is a fun experiment to visually demonstrate that when clouds can’t hold any more moisture from the air, it precipitates as rain, snow, sleet, or hail. You only need a few things you already have around the house for this activity!

What you need:

  • Shaving cream
  • A large clear glass (or jar)
  • Water
  • Food coloring (we like to use blue, but any color will work)
  • A spoon


  1. Fill the glass about halfway with plain water. This represents the air in our atmosphere.
  2. Spray some shaving cream on top of the water to fill the glass to ¾ full. This represents a cloud.
  3. Be sure to spread the shaving cream smoothly over the top of the water so that there is a complete layer of shaving cream on top of the water.
  4. Mix ½ cup water with 10 drops of food coloring in a separate container. This will represent excess moisture in the atmosphere.
  5. Carefully add the colored water, spoonful by spoonful, to the top of the shaving cream.
  6. When there is too much colored water added, watch it storm!

Eventually, the colored water becomes too heavy for the shaving cream “cloud” to hold up, and the colored water will rain down below the “cloud”. You can also have fun with variations on this experiment. What happens if you use more shaving cream? Less? Can you recreate a drizzle or a downpour? Have fun watching the rainstorm in the glass!