GRAND RAPIDS — A floating ping-pong ball… How can we make a little ball float without even touching it? This month's experiment will teach us about some of the forces acting against it. Let’s get started and figure how we can learn more about pressure and motion.
Here’s what you need:
Step 1: bend the short end of the straw upward
Step 2: while blowing through the straw place the ping-pong ball in the stream of air
Step 3: continue to change the amount of pressure you force on the air stream and watch what happens to the ping-pong ball
Did you get your ping-pong ball to float?!?! Multiple forces are acting on the ping-pong ball. A force is a push or pull putting an object in motion, right? Here gravity pulls the ping-pong ball down toward earth while our breath pushes the ping-pong ball back upward. Each force has both a strength and direction. The fast air stream flowing around the aerodynamic ping-pong ball creates lower pressure directly around the ball. The higher the pressure gets surrounding the ball it forces the ball into our stream of air. When we can get these two forces to balance, the ping-pong ball floats! You can also try this with a hair dryer!