Taking science by storm: thunderstorms

In the world of weather, convection and thunderstorms go hand in hand.

Put plainly, convection is the rising of warm, less dense air and the sinking of cold, more dense air in the atmosphere.

On a warm and humid day, the air mass near the surface is very buoyant (low density). This air will rise into a colder region and condense, forming clouds. If convection is strong enough, then thunderstorms will form.

Try this experiment to experience convection on a small scale.

Experiment

Materials:

• Large and small glass jar (small jar must be able to fit inside large jar)
• red food coloring
• plastic wrap or aluminum foil
• rubber-band
• knife

Instructions:

1. Fill the large jar with cold water (add ice cubes) about 3/4 full
2. Add several drops of red food coloring to small jar
3. Add near boiling water to fill the small jar
4. Cover small jar with plastic wrap or aluminum foil and secure with rubber-band
5. Carefully place small jar inside large jar
6. Cut the plastic wrap or aluminum foil to allow hot water to escape
7. Observe the hot water rise to the top and the cold water sink below