A tornado is a vortex created by a large (supercell) thunderstorm that can grow to altitudes over 40,000 feet.

Twister In a Jar

The purpose of this experiment is to observe how a vortex forms.

8 oz. jar with lid

Water

Vinegar

Clear liquid dish soap

A pinch of glitter

1. Fill the jar 3/4 full of water.

2. Put in one teaspoon of vinegar and one teaspoon of dish soap.

3. Sprinkle in a small amount of glitter.

4. Close the lid and twist the jar to see a vortex like a tornado form.

As you twist the jar, the water inside up against the glass is pulled along due to its friction again the glass walls. The fluid toward the inside takes longer to get moving. But eventually both the glass jar and the fluid are spinning as you rotate the bottle. When you stop rotating the jar, the fluid inside keeps spinning. A mini twister can be seen for just a few seconds when the outer fluid slows down and the inner fluids continue to spin rapidly. Try it again!

We've discussed updrafts in the Make a Thunderstorm! activity. How would a column of air begin to rotate without a huge fan placed on top of the thunderhead?

This is not completely understood by scientists, but one way the rotation appears to happen is when winds at two different altitudes blow at two different speeds creating wind shear. For example, a wind at 1000 feet above the surface might blow at 5mph and a wind at 5000 feet might blow at 25mph. This causes a horizontal rotating column.

If this rotating column of air gets caught in a supercell thunderstorm, the updraft tightens the spin and it speeds up (much like a skater spins faster the arms are pulled close to the body. A funnel cloud is created.

The rain and hail in the thunderstorm cause the funnel to touch down creating a tornado.