Twisting Oreos to determine which side of the cookie the cream filling sticks to is a time honored tradition. For kids, it’s a great way to place a bet, or settle a variety of playground disputes with the help of the delicious confection.
And the probability was always chalked up to dumb-luck, or some blind happenstance determined by the fate of the universe. But according to Princeton University researchers, it has nothing to do with probability or the powerful whims of the cookie Gods. In fact, a study in 2014 concluded with a 100% rate of accuracy which side of the cookie gets the cream, and it all boils down to how Oreos are manufactured.
The group of graduate students in aerospace and mechanical engineering used high-tech machinery -- in addition to family and friends -- to conclude that every cookie inside an individual box of Oreos splits in half the same exact way. While it took a group of physicists to make the discovery, it’s pretty easy to test the findings yourself, as Quartz distills how to do just that: