Why does the room seem to keep rotating after I’ve stopped spinning in circles?
After you stop your body from spinning, the perilymph, or fluid in your inner ear, keeps swirling around for a few moments, just as soup in a pot keeps swirling for a second or two after you stop stirring it. That small amount of fluid causes tiny hair-like sensory cells that line the bottom of the inner ear to bend in the direction of the swirling, much like seaweed on the ocean floor tilts in response to current. It takes a few moments for the perilymph to come to a standstill and for the sensory cells, called cilia, to return to their upright position. That lag time is what gives you the odd perception that the room is spinning.
The normal position of the cilia at rest is upright. When the cilia are tilted in one direction, as from spinning, the mechanical energy of spinning is converted into electrical energy. These electrical impulses travel from the cells through the nervous system to the brain, where they are interpreted as circular motion.
A dancer or figure skater performing a spin keeps her eyes fixed on one point in the distance during each revolution until the last possible moment. Her head is the last part of her body to make the turn, and she immediately refocuses her eyes on the same spot as soon as her head comes around the circle. Her perilymph doesn’t get enough momentum to swirl in a circle, preventing, or at least lessening, the sensation of dizziness and the perception that the room is spinning. And that’s a good thing, too. It wouldn’t be very graceful for a dancer to stagger offstage after the grand finale!