A small tabletop experiment for a direct measurement of the speed of light

TL;DR

This paper presents a simple, accessible tabletop experiment allowing undergraduate students to directly measure the speed of light with reasonable accuracy, including optional measurements of refractive index, suitable for diverse educational settings.

Contribution

It introduces a practical, low-cost experimental setup for measuring the speed of light that is suitable for non-specialist students and includes analysis of its accuracy and limitations.

Findings

Achieved measurement accuracy within a few percent

Demonstrated the experiment's accessibility for undergraduate labs

Discussed safety and practical considerations for implementation

Abstract

A small tabletop experiment for a direct measurement of the speed of light to an accuracy of few percent is described. The experiment is accessible to a wide spectrum of undergraduate students, in particular to students not majoring in science or engineering. The experiment may further include a measurement of the index of refraction of a sample. Details of the setup and equipment are given. Results and limitations of the experiment are analyzed, partly based on our experience in employing the experiment in our student laboratories. Safety considerations are also discussed.