Experiment
Flying ball
Make the goop bounce with the help of static electricity!
Curriculum objectives - Science
- Asking questions and creating hypotheses about science phenomena, identifying variables and gathering data to find answers
You need:
- Hair dryer
- Ping-pong ball
This is what you do:
Connect the hair dryer and turn it on.
Set it to the highest setting and point it straight up.
Place the ping pong ball over the hair dryer and see what happens.
Observe:
Make a hypothesis about what you think will happen. What's up?
Record your observations.
Explore further:
Test your skills: see how far you can tip the hairdryer to the side before losing the ball. Why does the ball stay in the air stream?
Take a toilet paper roll and place it over the ball. What's up?
What is going on?
The ping pong ball will fly up with the air from the hair dryer until it reaches a balance point - that is where the force of gravity (pushing the ping pong ball down) equals the force of air (pushing the ping pong ball up).
The ping-pong ball stays within the column of air coming from the hair dryer due to air pressure. The air coming from the hair dryer moves faster than the air around it, and this means that it has a lower air pressure than the air around it. (We know this thanks to our old friend Bernoulli, who discovered this relationship in the 18th century). So the ball is kept within the column of lower air pressure due to the higher pressure air surrounding it.
Where else do we use air pressure to keep things afloat? Think of an airplane: the shape of the airplane wing causes air to move faster over the top of it than it does under the wing. As we saw with the table tennis ball, this means that there will be lower air pressure above the wing than below it, which will push the plane up and keep us afloat!
