Tornado in a Glass

A tornado, also called twister or cyclone, is a violent rotating column of air extending between the Earth’s surface and the base of a thunderstorm.

This vortex of wind, usually funnel-shaped, can be very destructive.

It can destroy large buildings, uproot trees, drive sticks into trees and hurl cars hundreds of yards away.

In this experiment, we will make a water tornado safely at our own home. Let’s see how a rotating vortex is formed.

Materials

• water
• liquid dish soap
• chunky glitter (optional)

Tools

• a tall glass or jar (lid is good but optional)
• a stirrer (if there is no lid, you can use pencil, chopstick, straw or an actual stirrer to stir)
• adult supervision

Instructions

1. Fill the glass with three-quarters of water.
2. Put a few drops of dish soap into the water.
3. With one hand holding the glass, use the other hand to stir the water quickly in a circular motion until a vortex or column of spinning bubbles is formed.
4. If you prefer to use a lid, cover the jar tightly and rotate the jar in circles using your wrist.
5. Then remove the stirrer, or put down the jar, and observe.
6. Add chunky glitter to see how the water current moves inside the glass (optional).

Notes

When you stir or spin the water, a vortex is created in the center, similar to the vortex in tornadoes. 

In a vortex, the water swirling on the outside has to move faster than the water on the inside to keep up.

This is why in a hurricane, strong winds are felt far away from the center but the center itself (eye) is calm.

Here’s a printer-friendly version of this experiment for you. Enjoy!