Why the Ping Pong Ball Floats in Air

A simple way to demonstrate Bernoulli’s Principle  is to blow upward through a straw at a ping pong  ball. Bernoulli’s  Principle states that the pressure and   speed of a fluid are related such that when  a fluid moves faster, its pressure decreases.    And let’s pause the video for a moment when the  ball when is to the left of the straw. When the   ping pong ball moves out of the stream of air,  or to the left in the paused demonstration,   the air to the right of the ping pong ball is  moving faster than the air to the left of the   ping pong ball. That means the pressure to  the right of the ping pong ball is less than   the pressure to the left of the ping pong  ball. That pressure difference pushes the   ping pong ball to the right. And now we can  unpause it. That makes it so the difference   in pressure on the ping pong ball always  draws the ping pong ball towards the stream   of air moving upward from the straw, as long as  I can keep blowing air through the straw. Again,   the ball stays in the stream of air above the  straw because of Bernoulli’s Principle. And …