Why are Olympians always biting down on their gold medals after a big win? Turns out, it's got a little something to do with science.As Bustle points out, a new video from Today I Found Out breaks down some of the reasons why the Final Five and other athletes have been putting their gold medals in their mouth. Turns out it's part of a long tradition of testing whether a metal is pure.Gold is actually a soft metal that we can sink our teeth into, quite literally. So taking a bite out of it was a way to find out its purity. Basically, if your teeth leave a mark in the metal, you know it's actually real gold.If it was gold-plated, biting down on it would reveal that underneath that gold exterior lies something not nearly as shiny, like lead.While Olympic gold medals are no longer made of solid gold — this year, they're actually only 1.34 percent gold — up until 1912 they actually were. Back then, this made the bite test a good way to make sure you really were taking home the gold.But, the video also says that while science is part of the reason Olympians still bite down on their gold medals, the fact that a nice chomp down on any medal is a good photo opportunity is the real reason it's still so prevalent at the games.So basically, don't expect biting medals to go out of style anytime soon, even if the science behind it is no longer an exact one.