A Short Foucault Pendulum Free of Ellipsoidal Precession

TL;DR

This paper introduces a quantitative method to eliminate ellipsoidal precession in a short Foucault pendulum, making Earth's rotation precession observable and improving the practicality and accuracy of tabletop Foucault pendula.

Contribution

A novel, robust technique to remove intrinsic ellipsoidal precession, enhancing the clarity and feasibility of observing Foucault precession in small-scale pendula.

Findings

Successfully demonstrated suppression of ellipsoidal precession in a three-meter pendulum.

Enabled clearer observation of Earth's rotation precession in short pendula.

Method is insensitive to perturbative force size and direction.

Abstract

A quantitative method is presented for stopping the intrinsic precession of a spherical pendulum due to ellipsoidal motion. Removing this unwanted precession renders the Foucault precession due to the turning of the Earth readily observable. The method is insensitive to the size and direction of the perturbative forces leading to ellipsoidal motion. We demonstrate that a short (three meter) pendulum can be pushed in a controlled way to make the Foucault precession dominant. The method makes room-height or table-top Foucault pendula more accurate and practical to build.