Arrange the materials as shown in the diagram below.
The pencil should stick out over the edge of a table/desk at an angle. It should be stuck to the surface with sellotape.
The thread should be taped to the surface also and draped over the pencil.
A paper clip bent into a hook shape should be at the free end of the thread.
Put one washer on the hook.

Hold the washer in your hand, pull it to one side and let it go. Make sure that it can swing smoothly, without bumping off anything.
With your watch, find out how long it takes for your pendulum to swing over and back 10 times.

Would your pendulum take a longer or shorter time to complete 10 swings if you made the following changes?
You should discuss each of these with your partner before making a joint prediction.
 
change our prediction
add washers to the hook
 
 
 
pull the weight more to one
side before letting go
 
 
make the thread longer
 
 
 
make the thread shorter
 
 
 

Once you’ve made your predictions, go ahead and test them!
Record your results below
 
change  our prediction our result
add washers to the hook
 
 
   
pull the weight more to one side before letting go
 
   
make the thread longer
 
 
   
make the thread shorter
 
 
   

Write down what you’ve learned about pendulums on the next page.
Ask your friends to do the same investigation and find out if they get the same results.
Do your results give you any clue as to why pendulums are used in clocks?