5ml of petrol is sprayed into a 10 litre water container, which is empty apart from air. The bottle is placed upside-down and the gas mixture inside is ignited at the bottleneck with a lighter. With a loud "whoosh" a jet of flames erupts, rising about 20-30cm out the top of the bottle.
How does it work?
In the bottle there is a highly flammable gas mixture. When the gas is ignited it quickly becomes hot and rapidly increases in volume. However the gas can only expand through the open bottleneck, driving the flames out with it. In an internal combustion engine, this force is used to move cylinder pistons.
