Special Relativity
Light in vacuum has the same speed in every inertial frame. Use this to compare moving clocks.
↔ Drag to explore
Principles and uses
Use a light clock to examine time dilation.
Light speed in vacuum is invariant across inertial frames, while the observed path depends on relative motion.
The stationary observer sees a longer light path in the moving clock. Equal light speed makes its measured period γ=1/√(1−v²/c²) times longer.
Use it to understand the time-dilation factor and compare clocks from a specified reference frame.