Hooked on Science: Shaving cream rain

Using a few materials from around the house, you can get a better understanding of how rain falls from the clouds.

Materials

* Shaving cream

* Blue food coloring

* Cold water

* Transparent cup

Instructions

STEP 1: Fill the transparent cup 3/4 of the way with cold water.

STEP 2: Spray the shaving cream on top of the cold water.

STEP 3: Squeeze several drops of the food coloring on top of the shaving cream and observe.

Explanation

The saving cream represents the cloud and the blue food coloring represents the rain. As water droplets inside a cloud continue to grow, they become heavy enough to fall to Earth. The same thing is happening in this experiment. The shaving cream becomes so saturated, the food coloring pushes through into the cold water. Molecules in the cold water are moving slowly, therefore it takes longer for the food coloring to spread throughout the water. This makes the food coloring look like streams as it pushes into the water.

Jason Lindsey is a science outreach educator with Hooked on Science. Check out his website www.hookedonscience.org for webcasts and experiments.