|MadSci Network: Chemistry|
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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