"Funnel, ping pong & hose" Return to list of pracs

Aim: This activity is used to make predictions about what would happen placing a ping pong ball in a funnel attached to a hose that someone blows through.

Equipment: The equipment includes...  

• plastic hose attached to funnel;
• ping pong ball.

Method: Attach the plastic hose to the base of the funnel. Place the ping pong ball in the funnel. Ask thequestion "Would will happen to the ping pong ball when I blow through the tube?" Brainstorm all the possibilities (stays where it is but rolls around; flies out; moves up into the air and remains suspended etc). Also ask the question "What will happen to the ping pong ball when I blow through the tube but hold it upside down?"

Background knowledge: Air passes rapidly through the tube and passes around the edges of the ping pong ball. This causes a lower pressure at the hose end of the funnel. On top of the ball, slower moving air results in higher pressure. Therefore, with lower pressure below and high pressure above, the ball tends to be held tightly in the tube. Whether it is upside down or not, the ball is "sucked" into the tube.