Hd-2 The Fire Syringe
Aim
To demonstrate the generation of heat during compression of air.
Apparatus
- Fire syringe kit
- Match heads or small pieces of tissue
Fire Syringe Apparatus.
Description
The demonstration consists of placing within the combustion chamber scrapings from a match head. Forcing the piston rapidly down compresses the air adiabatically and raises its temperature to approximately 1000°K whereupon the match head ignites. It is possible to use a small piece of tissue paper instead of the match head but the demonstration is difficult.
In a typical compression the volume decreases by a factor of 20. Both nitrogen and oxygen, the primary constituents of air have gamma=1.4.
If T=300°K
Tf=300K.(20)^0.4
which yields T=994°K