MadSci Network: Chemistry
Query:

Re: What is the ignition temperature of the head of a safety match?

Date: Tue Sep 22 00:47:55 1998
Posted By: John Christie, Faculty, School of Chemistry, La Trobe University, Bundoora, Victoria, Australia
Area of science: Chemistry
ID: 906379962.Ch
Message:

The whole idea of the safety match is that it will only ignite as the 
result of heating two chemicals together. One chemical is in the roughened 
box side, and the other in the match head. The heat is supplied by 
friction. As far as I am aware, the chemical in the match head is primarily 
simple sulfur. 

As a rural Australian, I am sure you also know that you can strike a safety 
match by supplying heat to achieve a somewhat higher local temperature, 
with a more effective friction. This is usually done by striking the match 
head on plate glass. I do not think the Wild West trick of striking it on 
your boot will work with our safety matches -- I have never been able to do 
it, anyway. And of course you also know that if you hold a match head just 
the right distance from an open fire, it will spontaneoously flare up.

The ignition temperature of a safety match head is designed to be quite 
high, to avoid accidents with unintended combustion. But once the reaction 
gets started it is designed to get going rapidly -- the flaring of the 
match head.

In my chemical reference books the ignition temperature of sulfur is listed 
as roughly 230 deg C, and I think that would be pretty close to the 
ignition temperature of a match head. This is the temperature a match will 
flare at if you hold it near a heat source (i.e. not in a flame, but in a 
suitably hot region). 

As to why a tram driver would need to know, I'll have to admit defeat on 
that one. Perhaps the exam was a general Public Service exam for all 
Victorian Government jobs. In those days MMTB (Melbourne trams) or SEC 
(State electricity authority, which ran Bendigo trams) were both State 
Government Authorities. And while it may not be important for a tram driver 
to have known the ignition temperature of a match head, it would probably 
have been vital for a Spring Street pen-pusher, or maybe even an 
electricity meter reader ;-)



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