Science behind the pendulum

A weight, a wire, and a rotating planet.

A simple pendulum is defined as a weight suspended from a fixed point that swings freely due to the force of gravity.

Precession period

T = 24 h / sin(φ)

φ ≈ 41.5° (Avon Lake) → T ≈ 36 h

Foucault Pendulum

Like a simple pendulum, a Foucault Pendulum is hung from a fixed point and is free to oscillate.
A Foucault Pendulum is a type of pendulum that shows the rotation of the earth by oscillating over a fixed point while the Earth rotates beneath it.
Foucault pendulums complete a full rotation in 24 hours on the North Pole and do not rotate on the equator.
Because of Avon Lake's latitude, it takes roughly 36 hours for the pendulum to complete a rotation.

A fully functioning Foucault pendulum is an autonomous system.
It has to maintain an amplitude and precession without additional interference, however, as the pendulum swings, it loses energy due to air resistance.
Additionally, the way the pendulum is held at its pivot point (where it is attached to the ceiling) can affect its rotation and introduce friction which causes the system to lose energy.

To reintroduce energy to the system, we are using an Arduino microcontroller, which turns on an electromagnet when the hall effect sensor is triggered.
The electromagnet ensures the pendulum maintains its amplitude and precession (its circular movement) by pulsing the magnet to push the bob along its path.

For the Foucault pendulum to accurately represent Earth's rotation, it must maintain a specific amplitude.
The amplitude of the pendulum is the maximum displacement of the bob from its position at equilibrium.

Precession is the illusion that the pendulum is rotating in a circle as it swings.
In actuality, the bob itself continues swinging in a line due to its inertia as the Earth completes its rotation beneath it.
Because of this motion, the pendulum will appear to move 360 degrees, but the resulting motion is a representation of the Earth's rotation.