Gas Compression - Hyman Fire Piston
The Hyman Fire Piston demonstrates the rise in temperature when a fixed mass of gas is compressed. A portion of tinder supported inside a transparent cylinder is ignited when the contained air is compressed by a hand operated piston. Suitable tinder is provided, though almost any organic material will do if dry enough, i.e. cotton, charcoal, tissue paper.You can also demonstrate the need for oxygen to support combustion by attempting to re-ignite a piece of tinder. It will only occur if the piston is completely removed from the cylinder and a supply of fresh air introduced. A cloud can be formed in the cylinder by, having compressed the air inside it, allowing a sudden decompression. The reduction in pressure lowers the temperature and immediately condenses the water vapour inside the cylinder. This can be seen quite easily, but is often mistaken for smoke given the combustion that has already taken place.