Harmonics  (Anna Creekmore)

One fun one I used last week while tutoring is working with sound. 

Purpose : We were discussing the harmonics and how it all depends on the length of the pipe and if it is open or closed on the end.

Items Needed: 
1) Download the free app: ToneGenerator (or any other equivalent app)
2) Buy: Long skinny water squirters from dollar tree ($1 each), then cut the tip off with box cutter

How to: 
Do: Play a certain frequency note, find where the note is the loudest as you move the handle closer and farther apart. take a marker when you find it and make a mark, look for a second, third, etc. spot where it does the same. 

Math: Use the closed end pipe equation to solve for the length the pipe should be for the first harmonic.
Measure: what was the length from the end of the pipe to the closest "loud spot". Calculate: find % error. 

f = v/4L   v=343 m/s

Result
The other day we did it at my dining table, played a 600 Hz tone, and got a 1.2% error. Which I thought was pretty cool and my friend thought it was really cool too. If none of that made sense, I can make a video demo so that everyone could see it.