You can easily create your own small tornado in a bottle, which illustrates the principles of tornado formation.
What you’ll need: A large plastic litre bottle with a cap (a fizzy drink bottle is ideal), Pebbles or marbles, Water with 2 drops of washing up liquid in it.
What to do: 1. Fill the bottle with the water and washing up liquid.
2. Place the stones or marbles into the bottle.
3. Shake the bottle in a circular motion. The stones will spin round the walls of the bottle. Put the bottle down and watch it. What do you see?
Results: Hopefully you will have seen a mini-tornado spinning around in your bottle.
This process is quite similar to how tornadoes form in nature. Real tornadoes are formed when the strong air currents (updraughts and downdraughts) within a storm cloud create a high speed vortex (spiral) or funnel of winds. A 'funnel cloud' develops first from the base of the cumulonimbus cloud and this may then extend down to ground level. There is very low pressure at the centre of the vortex and it’s the same in tornado the bottle. The spinning vortex of air and air bubbles is at a lower pressure than the water around it. If a real tornado goes over a building it can explode outwards because of the sudden drop in pressure as the vortex passes over the building
The real destructive power of a tornado comes from the winds which the difference in pressure causes. Near the core of a tornado, winds may spiral around at more than 480 km/h (300 mph) causing the extreme and concentrated damage on a tornados path.