Inertia Balance
   When I came to teach at Kenyon in the fall of 1964, the first experiment used the inertia balance. Various masses were placed on the platform that was set into side-to-side oscillations, and the corresponding periods timed. A graph of the period as a function of mass was drawn, and then the students timed an unknown mass. Its period was then used to read the mass off the graph  It was an ideal first experiment -- the students did not have to know any theory, they learned something about timing operations, had a chance to graph some data and do some interpolation. Foolishly I replaced it in the next year. Today I would use it again.

   The apparatus was $35.50 in the 1950 Cenco catalogue.

Ref: William Schreiver, "A New Inertia Balance and Operational Definition of Mass", Am. Phs. Teacher, 5, 2002 (1937)
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