Clock-comparison experiment

Clock-comparison experiments are tests of the theory of relativity and may refer to:


 * Hafele–Keating experiment, comparing the drift in cesium beam atomic clocks on airplanes.
 * Hughes–Drever experiment, comparing energy levels of nucleons or electrons
 * Optical cavity tests, comparing laser frequencies
 * Pound–Rebka experiment, comparing clock rates to test gravitational redshift
 * Gravity Probe A, comparing clock rates to test gravitational redshift