Before you ingest enough alcohol to make your head spin this New Year's, fill your head with scientific knowledge about what booze actually does to your body. Apparently, that stuff goes just about everywhere—even into the structures and fluids of your inner ears. Armed with only a white board and science, one YouTube user explains how your ears trick hungover you into believing that your head is spinning around and around, even when it's just lying pathetically on the couch, attempting to chart the quickest path to carbohydrates.

Here's how it works: The semi-circular canals of your inner ear are outfitted with a fluid called endolymph and a gelatinous structure called the cupula. Together, they interact with one another to send messages to your brain about how your head is moving through space. When you rotate your head, inertia causes the movement of the fluid to lag behind the more solid cupula, and your brain understands that you're spinning in circles. But the system isn't perfect: When pilots take particularly long turns, for example, that fluid eventually overcomes inertia and catches up; when the plane levels out, the pilot's ears can make it feel like the plane is still turning even when it's flying steady.

Drunk people are kind of like sad, confused pilots on the ground: When they ingest too much alcohol, the fluid in their inner ears plays tricks on them, too. Because "alcohol diffuses into different parts of your body at different speeds," the booze tends to build up more quickly in your inner ear's gelatinous cupula than it does in the surrounding canal fluid. And because alcohol is lighter than water, the cupula wants to float in the denser fluid, unmooring your center of gravity and making your brain believe that it's accelerating toward one side. Over time, the alcohol will diffuse into the fluid, too, stopping the spinning sensation. But later on—say, when you're waking up to a splitting hangover—the alcohol will begin to exit the cupula faster than it does the surrounding fluid, and you'll feel the same spinning sensation, this time in the opposite direction.