Ask A Scientist Chemistry Archive

Question:
One of my students showed me a novel way of striking
a safety match. He briskly struck the match across a
dollar bill and the match lit! How come?  We've tried
striking the matches on various weight paper, emery
boards, cardboard, construction paper etc. all with
no success. I thought you could only strike a safety match
on the black "striker" on the cover of the match book. What
gives? We also think that part of the safety match system
involved the use of red phosphorous...eguzdziol
 
Answer 1: 
Interesting question.  Although I don't profess to know
much about matches, I may be able to theorize, if you'll
indulge me a moment. What lecturers refer to as the
"match-head reaction" is the reaction of red phosphorous
and potassium chlorate.  The vigor with which this reaction
takes place is determined by the ration of amounts of
the two reactants -- equal proportions creating a rather
loud and, smoky explosion.  I believe safety matches have
less potassium chlorate, and thus require a surface with
a specific amount of friction to it in order to light,
while those "strike anywhere" matches have more potassium
chlorate, and work more like the "match-head experiment,"
which gains its energy of activation from a strike of a
hammer (the way I do it, anyway..)  The dollar bill, with
its proportion of cotton fibers woven into the paper pulp
must therefore provide the right kind of friction for the
safety matches to ignite.  *shrug* correct me if I'm wrong,
people -- just speaking exact cathedra from my belly button...
 
--WORD!!
 
Answer 2: 
Sounds correct to me. You're definitely right about
the difference between safety matches and regular matches.
 
-dr topper