Galileo, a famous inventor who lived about 400 years ago, came up
with an idea similar to this for making a time measuring
instrument. His idea came from watching a lamp swinging back and
You will need:
- Weights (any objects which you can tie to the string)
- A piece of wood about $1.5$m long
- A hook
What to do:
- Tie a weight onto the end of the piece of string.
- Make a loop at the other end of the string.
- Screw the hook into the piece of wood and balance the wood
between the backs of two chairs.
- Put the loop of string over the hook.
You have now made a pendulum and can
begin to experiment to make a minute timer from it.
- Start the weight swinging and time how long it takes to make
$20$ swings. Use a stopwatch for this.
- Find a way to make the pendulum swing $20$ times in $20$
Experiment with different size weights.
Try different lengths of string.
Can you turn your pendulum into an accurate minute timer?
This activity features in our
December 2008 Advent Calendar.