Fizeau's "aether-drag" experiment in the undergraduate laboratory

TL;DR

This paper presents a simple, cost-effective undergraduate experiment that demonstrates Fizeau's aether-drag effect, confirming relativistic predictions through laser interferometry with moving water.

Contribution

It introduces an accessible experimental setup for undergraduates to observe relativistic effects, combining optics, fluid mechanics, and data analysis in a practical physics lab.

Findings

Good agreement with relativistic predictions

Successful measurement of phase shift caused by moving water

Practical demonstration of relativistic effects in a macroscopic system

Abstract

We describe a simple realization of Fizeau's "aether-drag" experiment. Using an inexpensive setup, we measure the phase shift induced by moving water in a laser interferometer and find good agreement with the relativistic prediction or, in the terms of nineteenth century physics, with Fresnel's partial-drag theory. This appealing experiment, particularly suited for an undergraduate laboratory project, not only allows a quantitative measurement of a relativistic effect on a macroscopic system, but also constitutes a practical application of important concepts of optics, data acquisition and processing, and fluid mechanics.