This impressive demonstration shows that the simple harmonic motion of a tuning fork is really a sine wave in time. A laser beam is bounced off a mirror on the end of a tuning fork to a rotating mirror which provides the time axis. The tuning fork is driven by an interrupted magnet.
![](/sites/default/files/demomanual/harmonic_motion_and_waves/simple_harmonic_motion/laser_sine_wave_from_tuning_fork.gif)
![](/sites/default/files/demomanual/harmonic_motion_and_waves/simple_harmonic_motion/lsrsnwvs.gif)