The Steampunk Satyricon

Sunday, June 13, 2010

The Greek Alphabet: Math Without Numbers (kind of)

This is the sort of thing that drives people away from science:

It's a formula for the magnitude of an electric field as a function of time in an unmagnetized plasma. It's math, but you don't see any numbers. There are numbers there, but they're hidden behind the letters and those mysterious symbols. For the layperson, it makes no sense, even when you realize that most of those "mysterious symbols" are just Greek letters.

Blame Diophantus of Alexandria (c. 200 A.D., but reports of the exact dates of his lifespan vary widely). Before this Greek mathematician came along, equations were simply expressed as sentences written out in words. Diophantus is credited as being the first to use symbols to stand in for the numbers that change (the variables) and the numbers that are used repeatedly (the constants) in different equations. For many centuries after Diophantus, lessons in Latin and Greek were a common part of any aspiring scholar's education, and using Greek letters as symbols in mathematical equations was just the tradition and no big deal.

These days, Greek letters are more commonly associated with fraternities and sororities (at least for the less-than 30% of Americans who have college degrees). One reason equations like the one at the beginning of the post seem so intimidating is because they look so freakin' strange, very much like another language. Check that... mathematics is another language. If you're going to learn it, and stop being intimidated by it, it is helpful to recognize the letters of the Greek alphabet:
If the equation is being presented properly, it should be apparent what the author means for each symbol to represent. A mark's meaning can change depending on which branch of science you're dealing with, but I've never seen the character pi represent anything other than 3.14159,blah,blah,blah. There are other freaky non-Greek symbols to learn, but that's for another post. Download this PDF (127 K) containing a Greek alphabet cheat sheet.

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