Recently I opened a drawer and found a set of “train whistles” that I made in my woodshop 30 years ago. Some of them are shown in Fig. 1. Making these is a good exercise in simple woodworking for high school physics students, and gives them something to take home. The train whistle is a first cousin of the organ pipe.1,2
The lower object in Fig. 1 is a small organ pipe. About 1990, the Kenyon physics department discovered that a local church was replacing its organ, and we bought 100 of the discarded pipes at a dollar each. When I discussed the operation of the organ pipe for my premed class, each student was given a pipe to examine, and then “toot!”
Organ pipes consist of two parts. At the lower end, there is a whistle that produces white sound—a range of different frequencies. The upper half...
