School of Physics Lecture Demonstration Manual

Hd-2 The Fire Syringe

Published: Monday 13 March 2006 - Updated: Monday 28 March 2011

Aim

To demonstrate the generation of heat during compression of air.

Apparatus

Diagrams

Click on pictures to enlarge.

Fire Syringe Diagram

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 temperatureto 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

Safety notes

Fire/Burn Safety 

Personal Protection 

Maintenance 

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