Thursday, March 09, 2006

Matches, Poo, and You: a lesson in everyday chemistry

I'm an inherently curious person. Sometimes, when I'm eating something, I'll suddenly wonder where it came from and what it looked like in its original form. Like... hmm. I wonder what asparagus looks like when it's growing in the ground. Well, look at that! Asparagus grows out of the ground looking like someone took it off your dinner plate and stuck the stalks vertically into some soil! So I guess you can understand that Wikipedia and Google Image are two of my favorite favorite places to surf (with the exception of Huntington Beach and North Shore, O'ahu, hee). They help me stop wondering, and start knowing. And boy, do I wonder a lot.

The latest thing I've looked into is something I've wondered for a long time. It's quite a nugget of useless if magical scientific knowledge... Now. Many of you (by which I mean maybe one or two of the handful of you who actually read this) may be members of the light-a-match-after-you-Number-Two community. *Handshake* I, too, am such a member. How does it work? How is it that the act of lighting a match makes the smell of poop disappear? I recently went on a quest to find out. It was an entertaining quest in which I discovered lots of things, like the presence of hundreds of message boards filled with questions and comments about poop. There's a whole community of poop-obsessed out there. It's thriving, I tell you. It's quite something. Strangely enough, I couldn't actually find a direct answer to my question. Maybe I wasn't doing a good thorough search, but I tend to think my internet search abilities are pretty strong... Anyway, this is what I've come up with:

First, I asked,
Q: Why is poop smelly?
A: The culprit is hydrogen sulfide [H2S(g)], the inorganic gas that also gives rotten eggs and farts their offensive reputations. It's produced (among other compounds, including sulfur-containing compounds) by our friendly intestinal bacteria as they help us digest. An interesting factoid about hydrogen sulfide: it burns to give the gas sulfur dioxide[SO2(g)], which smells like a burnt match.

2H2S(g)+3O2(g)--->2SO2(g)+2H2O(l)

This leads us to...
Q: How does the burning of a match lead to the oxidation of hydrogen sulfide to sulfur dioxide?
A: The heads of matches contain, along with glue and color and stuff, sulfur and oxidizing agents like potassium chlorate. The striking surface on the box contains red phosphorus, as well as coloring and stuff to provide friction. When struck, the heat from the friction of match+surface causes a some red phosphorus to become white phosphorus vapour, which burns spontaneously in air and initiates the decomposition of the potassium chlorate. This liberates oxygen [O2(g)]. The sulfur ignites and lights the wood of the match.

So for the overall
Q: How is it that lighting a match = poopysmell-be-gone?
A: Lighting a match causes the smelly poop gas to burn, converting it to another gas, which smells like burnt match, which is what the bathroom already smells like, because there's a burnt match in the room.

Hooray. Thus ends your lesson in the chemistry of poop & matches. *curtsy*

1 comment:

Anonymous said...

lol, wow, you really do know everything!