A few years ago I received a set of tuning forks for my science lab. Other than having students just play with them and end up with a headache by the end of the day I decided to come up with a lab that would use the tuning forks and show the relationship between pitch and frequency. Tuning forks are a cheap lab equipment and students love working with them. If you have the opportunity to get some I strongly recommend it. This lab has now been updated to included working with palm pipes made out of PVC. I used the 1/2" PVC but they can also be made with 1" PVC.