Rain in a jar
A shaving-foam cloud on top of water, drops of colour on it… and suddenly it starts raining in the jar.
Age : age 3+
Materials
- A big jar or clear vase
- Water : Three quarters of the jar.
- Shaving foam : The grown-up puts it on.
- Liquid food colouring diluted in a little water : Blue for rain, or several colours.
- A dropper or spoon
Steps
Make it rain
- Fill the jar three quarters full of water.
- The grown-up puts a thick layer of shaving foam on the water: that's the cloud.
- With the dropper, drip diluted colouring onto the cloud.
- Keep going, drop after drop… and watch under the cloud.
- When the cloud is too heavy, streaks of colour fall into the water: it's raining!
A real cloud is made of billions of tiny water droplets. When they join up and become too heavy, the cloud can't hold them any more: they fall, and that's rain. In the jar, the foam holds the colour until it's too full, then lets it through.
Several colours in different spots on the cloud make rainbow rain.
If it goes wrong
- It won't rain : Less foam, or more drops in the same spot.
- It falls too fast : Add more foam.
- Colour is pale : Less water in the colouring.
Safety
- Shaving foam doesn't go in mouths or eyes; with little ones, the grown-up handles it.