bc wonders if Ann teaches the pendulum is isochronous.
Bernie - you are a bit of an horologist so this is an example that
strikes home for you I suspect.
Was Galileo's observation/measurement that a pendulum is sorta
isochronous not one of his important contributions to science??
A purist knows that you need to consider the details of the support
mechanism, the thermal properties of the materials involved, the
viscosity of the air, the rotation of the earth and innumerable other
complicating factors.
But I'll maintain that it's good for young'uns to know that a
pendulum has a pretty constant period.