Let's take a brief look at the chimes and try to understand the basic idea of how they work. Set up the chimes as shown below. Roll the ball and listen to the sounds.
Which chime has the highest pitch (note)? Which one has the lowest? Why?
Think of it this way. Imagine that you are holding a long, flexible stick in your hand and that you are waving it back and forth (as shown below). If you made the stick longer do you think it would go back and forth faster or slower? (It would go slower.) If you made the stick shorter would it go back and forth faster or slower? (It would go faster.)
This is similar to what happens when the ball hits the chimes. The chimes vibrate back and forth and give off sound waves, which are heard by your ears. The frequency of the sound waves corresponds to the frequency at which the chimes vibrate. Shorter chimes vibrate at higher frequencies, corresponding to higher notes. Lower chimes vibrate slower, corresponding to lower notes.
What happens if you roll the balls harder to hit the chimes harder? Do the notes change? No, but the sound is louder. This shows that the note of a given chime only depends on its length, but it will be louder if it is hit harder.