Measuring the Planck Length and the Speed of Gravity with a Newton Cradle and a Photogate

Abstract

We demonstrate how one can remarkably use a simple Newton’s Cradle combined with an accurate photogate (also known as time-gate or speed-gate) to deduce the speed of gravity, as well as the Planck length. We conducted 100 observations and found values quite close to those observed from other methods. The fact that we can extract the speed of gravity, as well as the Planck length, from just accurate measurements of the ball’s speed in Newton’s Cradle, is in line with the predictions from recent literature.