Mind Bender

Ok, this is for the world at large. It's an IQ question that's supposed to have a logical answer. Stumped me for some time now. So if anyone chances upon this, do think about it and send me the answer!!!

Here goes:

-There are 12 coins of equal shape and size
-However, 1 coin weighs differently from the 11 other ones, BUT, you do not know if it's heavier or lighter
-You are given a scale (same one as the scale that symbolises justice)
-You are given only 3 tries to determine the 1 coin that weighs differently from the rest

Ok, go figure...