Make a Thunderstorm

The last experiment I posted was a rather easy one geared toward a younger group, so today’s will be a little more involved. This is one of the best ways to teach about convection and how thunderstorms develop.  

What you need:

Clear plastic horizontal box (like a shoebox)

Red food coloring

Ice made with blue food coloring

What you do:

You need to make the blue ice cubes ahead of time.  I just filled a normal ice cube tray then put one drop of blue food coloring into each cube of the container before putting it in the freezer. 

NOTE: the blue food coloring stained my hands when I made the ice cubes initially, when I took them out of the tray and cleaning it, and when I put them in the box for experiment.  It washes off, but if that bothers you, I suggest wearing gloves at each of those points in this process.

When you’re ready to do the experiment, fill the container 2/3 with lukewarm water and let it sit for one minute

Place blue ice on one end and 3-4 drops of red food coloring on the other. The base state of the water has to be slightly warm so you can have one side of the container represent warm and you’re dropping the ice cubes in for cold. 

Now you have one side of the container that is warm (red), and one side that is cold (blue). Watch what happens! 

It’s important to understand that air behaves like water.  You can see the warm air is forced to rise by the cold air moving in. Warm air rises and cold air sinks which creates convection. Convection is the process of air rising and falling to create a thunderstorm.

Normally such a sharp difference between warm air and cold air like this would happen as a front (cold front or warm front) moves through. 

This is a great experiment to do in small groups, but you can adapt this for larger groups too! Instead of using water and food coloring, I use kids to help demonstrate. I pick a few volunteers from the group wearing warm colors (like red or orange) and a few wearing cool colors (like blue or purple) and have them line up like what we did with the red food coloring drops and blue ice cubes. Ask them to walk in their lines until they meet each other then mix up in the middle until you can’t see those distinct lines anymore.