Giant Tuning Fork - Physics Demonstrations - Giant Tuning Fork | Physics Undergraduate Labs

Strobe lights can trigger seizures in individuals with photosensitive epilepsy. Announce the use of strobe lighting before beginning and allow students who may be affected to leave or look away. Avoid prolonged exposure and do not point the strobe toward the audience.

Purpose

Stroboscopic illumination makes the 128 Hz vibrations of a giant tuning fork visible to the eye. Students observe simple harmonic motion in slow motion and connect mechanical oscillation to sound production.

Large metal tuning fork with cylindrical handle lying next to a portable strobe light unit with adjustable dial and reflector

Close-up of the two flat rectangular steel tines of the giant tuning fork

Figure 1: The giant tuning fork (128 Hz) and strobe light. Set the strobe to the 670–4170 RPM range; at around 1400 or 2000 RPM the fork's vibrations become visible in slow motion.

Figure 2: Close-up of the tuning fork tines. The tines vibrate in opposite directions at 128 Hz; their large size makes the motion visible under strobe illumination.

Giant Tuning Fork

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Safety Warnings

Warning: Strobe Light Precaution

Purpose