Physics Demo Videos: Waves and Oscillations

Physics Demo Videos: Waves and Oscillations

Videos of demonstrations illustrating concepts related to oscillations, waves, sound, and interference.

For other videos from our demonstration collection, please visit Physics Demo Videos. You may also wish to view our Video Lecture Series for short tutorials on topics from first year physics.

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Oscillations

Spring and Rotating Wheel.  The y-component of a point on a rotating wheel matches the motion of an oscillating mass on a spring.A mass hangs from a spring next to a rotating wheel
Chladni Plates. When a two dimensional object is vibrated, patterns of waves can be seen. The sand on the plate collects in the nodes, or areas of no motion, of the waves.Chladni plate shows 2D resonance

Wave propagation on a wave machine

Shive Wave Machine; wide section, single wave, free end. A wave propagates down the machine. At the free end it is reflected with the same amplitude and without inversion.
Wave machine, long rods, free end
Shive Wave Machine; wide section, single wave, fixed endA wave propagates down the machine. At the fixed end it is reflected with the same, but negative amplitude.Wave machine, fixed end
Shive Wave Machine; narrow section, single wave, free end. A wave propagates down the machine. At the free end it is reflected with the same amplitude. The wave on this section moves faster than the wave on the wider section.Wave machine, free end
Shive Wave Machine; narrow section, single wave, fixed end. A wave propagates down the machine. At the fixed end it is reflected with the same, but negative amplitude. The wave on this section with narrow rods moves faster than the wave on the wider section.Wave machine, short rods, fixed end
Shive Wave Machine; all sections, single wave, free end. A wave propagates down the machine, going from a wide section to a narrow section via a connecting section. As the sections get narrower, the wave travels faster.Long rod wave section coupled smoothly to short rod section
Shive Wave Machine; two sections, single wave, free end. When a wave hits the abrupt transition, as represented by going from the narrow to the wide section without the connecting section, most of the wave is reflected at the barrier. Compare to what happens when light travels from a medium with one index of refraction to another.Wave machines with long rods connected to section with short rods

Sound

Pasco Synthesizer: Pure Tones. A synthesizer is able to produce 'pure' tones, each being a single sine wave.Synthesizer

Waves on strings

Guitar strings: overtones. Touching a string kills all overtones except those having a node where touched.Plucking a guitar string
Guitar strings: mass per unit length. Strings of different mass per unit length yield different pitches.Plucking different strings
Guitar strings: tuning a string. Increasing tension increases the pitch.Adjusting the tuning pegs on a guitar
Guitar strings: changing length. Pressing strings down onto frets shortens the string, increasing the pitch.Guitarist is shown pressing a string down onto a fret
Guitar strings: tone. The relative intensity of different overtones changes the tone of the guitar. Strumming closer to the bridge results in more intensity in higher frequency overtones.Strumming a guitar

Waves in air columns

Pipe, closed end.   As the piston is moved out, the standing wave that is set up inside the instrument lengthens, producing a lower pitch. When the slide comes out, this changes from a closed end to an open end, and the pitch increases substantially. How much does the frequency increase?An adjustable length flute with slide
Organ pipes. Different lengths of pipe yield different pitches. Blowing harder can excite higher frequency modes.Person blowing an organ pipe

The Doppler Effect

Moving a tuning fork. Swinging a tuning fork toward the observer increases the frequency of the sound. Swing it away lowers the frequency.Instructor swings a tuning fork
Twirling a tuning fork. When the tuning fork moves toward you, the frequency of the sound you hear is higher. As it moves away ...Instructor spinning the tuning fork or a string
Doppler shift, sidewalk observer. The Doppler shift created by a passing car:
The frequency of the car's horn is higher when the car is moving towards you and us lower as it is moving away.
Approaching car
Doppler shift, observer traveling with source. Car horn as heard by a passenger in the car.Passenger listening to a car horn
Doppler shift, observer in a car meeting another car whose horn is blowing. The pitch change is even greater as the cars pass each other.Car approaching another car whose horn is blowing

Interference

Beats from two tuning forks. Tuning forks at slightly different frequency produce "beats," that is, sound whose volume varies periodically.Two tuning forks