Why Toast Falls Butter Side Down

You're holding that piece of toast. The butter is melting into the bread just the way you like it. But somehow it slips from your grip and away it goes, on a tumble toward the kitchen floor. On its way down, you have a fraction of a second to guess which side it's going to fall on. You hope it's not on the buttered side, but you're usually wrong. Why is that?

The answer isn't related to Murphy’s Law or to bad luck. It's physics.

Note how you hold the toast: at an edge, not at the middle. If you hold toast level with the ground with both hands and then release it, it will fall butter side up. But toast held at one end acts like a lever. When you lose the grip, the toast doesn’t fall straight but turns first. So the toast turns down first on the hinge of your thumb and forefinger's failing grip, and then completely slips from your hand and falls down, rotating as it goes. The force of rotation pushes the toast beyond a 90-degree angle. A piece of falling toast doesn’t have enough time to stabilize. After passing this partial rotation, the toast appears butter side slightly down and falls in that position, landing at about 180 degrees from its original position in your fingers. The inertia is not sufficient for the toast to keep rotating. It continues falling in butter-down position and lands that way. (The rotation effect is pronounced for elongated toast; it more often continues turning on its way down and lands butter side up.)

And that's the simple explanation. If you want a brief and more technical overview of the physics of falling toast, go here.