What factors affect the pendulum period?
In physics class, you may have learned that the period of the pendulum (the time required to complete a swing) depends only on the length of the pendulum and the acceleration of gravity. Therefore, at a fixed location on Earth, the length is considered to be the only factor determining the pendulum’s period. Since materials expand and contract with changes in temperature, the pendulum is sensitive to temperature (precision clock movements use a variety of means to compensate for this, most notably bi-metallic grids). In reality, however, there are other factors that influence a clock pendulum’s period. Wind drafts, barometric pressure, magnitude of the driving weight, escapement geometry, and shaft stiffness all have an influence on the pendulum’s period.
