Play with some pendulums using a coffee cup, a spoon, and some string.
|Tie one end of a string to a spoon.
Tie the other end to a coffee cup with a handle.
Ask a friend to help you by holding out a finger (or pencil) to hang your pendulum or use a pencil.
Make sure the coffee cup is close to your friend’s finger.
Have them put their other hand on the table under the coffee cup.
You hold the spoon end of the string to keep the cup from dropping, like this.
When you are ready, let go of the spoon.
Did the cup hit the table? If so, you need to try again.
Vary the length of the string.
If your parents aren’t happy with you playing around with the coffee cup, find some metal washers to tie to the ends of your string. Can you figure out the best ratio of washers?
What works better? A finger? A pencil?
Does this work every time? Why?