Get Your Science On: What Keeps the Ball in the Cup?

Victoria has a simple surprising experiment. What Keeps the Ball in the Cup?

What’s Going On?

The air blowing out of the cup is at lower pressure than the atmospheric pressure. So there is a higher force pulling the ball into the cup than blowing it away.

Materials

Electric blower or inflator with tubing (we used http://goo.gl/c5ARdD)
Top of a 2-liter soda bottle
A light plastic ball or balloon