Optional Practical: Falling cotton reel (copy)
In this practical a cotton reel will be dropped down a guide rod onto a spring as shown in the photo. When the reel hits the spring it compresses it then bounces back up again. If the spring is completely compresses you will hear it hit the table with a small bang. If not completely compressed then the noise is slightly less (boing). Try dropping the reel from different heights to see if you can hear the difference.