Experiment 3.7: Fire Piston
A small piece of tinder is poked into the hole in the lower piston. Subsequently, the upper piston is forced vigorously down.
The tinder ignites with a bright flash.
When a fixed mass of gas such as air is compressed rapidly it becomes glowingly hot (adiabatic compression). (If this compression is not done quickly enough the entropy has time to flow from the hot gas into the cold cylinder walls and the gas cools down.) This effect can be used to ignite a piece of tinder. Thereby, the air in the cylinder acts simultaneously as an oxidizer.
- Detailed description (pdf)