How does paint behave when it’s flying through the air? What happens to paint when it is not in a can, on a brush, or on a canvas? A crossbow which fires a projectile at the bottom of a can of paint offers a possibility of finding out. Because of the force of the projectile, the lid of the can bursts off, and the paint leaves the can. This causes the paint to move forwards through the air, until gravity grips it once again and pulls it down.