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A copier paper box
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A small 12 volt computer fan from a computer or
electronics store. It should be at least 3x3 inches (8cm X 8cm).
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A piece of clear plastic 10 X 17 inches (25cm
X43cm) If your really in a hurry, you can test your fog tornado with clear
plastic food wrap.
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A small plastic food container
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Dry ice (or other source of fog - see below)
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Black paint
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9-volt battery (if your fan doesn't plug in)
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Optional (but cool) battery-powered tap light
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Adult help
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Parts of the cardboard will need to be cut out
using an exact-o blade.This part is definitely for an adult - kids hurt
themselves every year trying to cut foam core and cardboard - don't let that be
you - know when to ask for help.
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Follow the diagrams below, cutting away the
areas marked in gray. IMPORTANT: Pay special attention to the placement of the
slots. In order for the tornado to work, the slots will need to be in the
correct place.
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The opening at the top should be just a bit
smaller than your fan.
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The opening at the bottom should be bigger than
the plastic food container.
 
Paint the inside of the box with flat black poster paint and
allow it to dry.
Tape (or hot glue) the clear piece of plastic into the large
window on the front. Be sure to keep the nearby slot open so air can flow
through it.
Attach the tap-light to the inside of the top of the tornado
box near the fan opening.
That’s it! Your Tornado Chamber is ready.
A note about the fog. I have found 3 decent sources of fog:
DRY ICE - Dry ice makes the best looking tornado, in my
opinion, which is why I give the directions for it here. Dry ice should only be
handled by adults. It can cause instant frostbite. Never handle dry ice without
thick gloves and always wear safety goggles. Only someone familiar with dry ice
and its dangers should handle it.
HUMIDIFIER - Many small humidifiers create a continuous source
of mist that works well for the tornado chamber. You will need to find a way to
mount the tornado chamber above your humidifier.
FOUNTAIN MISTERS - A fountain mister uses ultrasonic
vibrations to create a light mist. They can often be found in stores that sell
small fountains and in some pet shops.
FOG TORNADO TIME!
Turn on the battery powered light if you have one, and power
up the fan. (red wire goes on the skinnier lead of the 9 volt battery) and
place it on the top of the chamber with the breeze blowing up.
Place some small chunks of dry ice into your food container
and add some warm water to create fog.
Put your tornado chamber over the container and watch the
wonders of vortex currents at work!
As the fan forces air out of the chamber, air from outside
the box is forced in through the slots on the sides. The position of the slots
causes the incoming air to create a VORTEX (spiral) of air as it is drawn up
and out of the box. Real tornados form in a similar way using updrafts and
wind-shear (wind from different directions at different altitudes)
The project above is a DEMONSTRATION. To make it a true
experiment, you can try to answer these questions:
1. Can you control the shape of the tornado by covering up
parts of the slots?
2. Does a faster or more powerful fan change the shape of
the vortex?
3. Do bigger boxes make bigger tornados?
Abdul Rafay
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