Question: Why do I feel dizzy when I spin?

Reka Nagy answered on 14 Nov 2016:

That’s because the way your body perceives motion is via a part of the inner ear called the vestibular system.

This consists of canals capable of sensing our body’s motion in three dimensions. These canals are filled with a fluid and the movement of this fluid is detected by ‘hairs’ connected to nerve cells that carry this information to our brain.

When we start spinning, the fluid starts spinning too, telling our brains that we are, in fact, spinning. When we stop, the fluid still has some momentum so it keeps moving around, still telling our brains we are spinning even though we are not.

It’s like when you swirl water around in a cup and then put the cup down, the water will continue swirling for a while instead of stopping instantaneously.