How Does Pressure Affect the Movement of Air?
The station sign reminds students of Bernoulli’s Principle: As the speed of a moving fluid increases, the pressure within the fluid decreases. Students will suspend two ping pong balls from a horizontal dowel rod about five cm (two inches) apart and predict what will happen when air is blown between them. Then, they will take turns using the air cannon(s) to shoot a stream of air between the balls, observing and recording results. Air moving between the balls has lower pressure, so the balls are pushed into the middle by still air of higher pressure on the opposite side of the balls. (For teacher reference: this Web site illustrates how Bernoulli’s principle works, with an animation).
