Demos by PIRA

3A Oscillations


3A10 Pendula


  3A10.10Ball on string mounts on blackboard and pivots on lower rod.
  3A10.10Simple pendulum: Ball on a string.
  3A10.14Four pendulums on rod: Same mass, different lengths.
  3A10.17Four pendulums on rod: Same length, different masses.
  3A10.30Torsion pendulum with removable weights.

3A20 Springs & Oscillators


  3A20.10Mass on a spring.
  3A20.60Ball rolling in a spherical dish on OHP.

3A15 Physical Pendula


  3A15.20Physical pendulum: Steel bar with two pivot points.
  3A15.50"Sweet Spot": Meterstick pivot point changes with point struck.

3A40 Simple Harmonic Motion


  3A40.20Ball on turntable rotates beneath synchronized pendulum .

3A50 Damped Oscillators


  3A50.10Large damped oscillator (mass on spring) with various damping disks.

3A60 Driven Mechanical Resonance


  3A60.10Film : "Tacoma Narrows bridge collapse",silent, 4 min.
  3A60.24Driven oscillations in a multiple spring-mass system.
  3A60.40Driven harmonic oscillator: Motor driven mass on spring.
  3A60.50Unbalanced spinning wheel vibrates spring steel reeds.
  3A60.50Set of three coupled inverted pendulums on wood base.
  3A60.55Clock spring oscillator: Electrically driven and damped.
  3A60.60Inverted pendulum.

3A70 Coupled Oscillations


  3A70.10Wilberforce pendulum: Oscillates between rotation and up-down.
  3A70.20Two pendulums on a frame of flexible steel.
  3A70.25Two large pendulums coupled with spring.
  3A70.35Two balls hung on the same string, one in middle, one at the end.

3A75 Normal Modes


3A80 Lissajous Figures


  3A80.21Transparencies: Lissajous figures for OHP.
  3A80.40Lissajous figures with laser and two signal generators.
  3A80.40Lissajous Figures created with a two tuning forks with mirrors

3A95 Non-Linear Systems


  3A95.52Chaotic pendulum.

3B Wave Motion


3B10 Transverse Pulses and Waves


  3B10.10Rubber rope stretched across front of room.
  3B10.10Brass spring on white plastic sheet.
  3B10.30Torsional wave device, large or small.
  3B10.30Torison wave model.
  3B10.50Transverse wave model, hand-cranked.
  3B10.70Transverse 3-dimensional wave model, hand-cranked.

3B20 Longitudinal Pulses and Waves


  3B20.10Suspended slinky on threads for compression wave.
  3B20.35Longitudinal wave model, hand-cranked.

3B22 Standing Waves


  3B22.10Rope and strobe: Transverse standing waves, motor driven.
  3B22.60Model of longitudinal standing wave, hand-cranked.

3B25 Impedence and Dispersion


3B27 Compound Waves


3B30 Wave Properties of Sound


  3B30.01Ultrasound transducers (40 kHz) as both sources and receivers.
  3B30.20Measurement of speed of sound with microphone, speaker, oscilloscope.
  3B30.30Bell ringing in a jar evacuated with pump.
  3B30.50Breathe helium, voice pitch rises; breathe SF6, voice pitch lowers.

3B33 Phase and Group Velocity


3B35 Reflection & Refraction (Sound)


3B39 Transfer of Energy in Waves


  3B39.10Mechanical water wave model, hand-cranked.

3B40 Doppler Effect


  3B40.10Sonalert swung on the end of a string.

3B45 Shock Waves


3B50 Interference and Diffraction


  3B50.10Interference in a ripple tank uses arc lamp or incandescent light.
  3B50.12Ripple tank with plane or spherical water waves and barriers.
  3B50.55Large wood model of a double slit with hinged waves.
  3B50.55Large wood model of a double slit with hinged waves.

3B55 Interference and Diffraction Of Sound


  3B55.10Interference of sound waves from two speakers, same generator.
  3B55.40Acoustic interference with Quincke (trombone) tube and sonalert.

3B60 Beats


  3B60.10Beats with tuning forks on tuned cavities.
  3B60.20Beats from two speakers observed on an oscilloscope.

3B70 Coupled Resonators


  3B70.10One tuning fork with tuned cavity, drives another.

3C Acoustics


3C10 The Ear


  3C10.10Ear models.

3C20 Pitch


  3C20.15Galton's whistle: Compressed air whistle.
  3C20.16Steel spring pendulum, inverted, vibrates at 10 Hz.
  3C20.16Limit of audibility: Set of rods that ring at different frequencies.
  3C20.30Siren: large, electric motor driven.
  3C20.30Compressed air jet blows through spinning disk with holes.
  3C20.40Savart's wheel: Toothed wheel and cardboard or air jet.
  3C20.40Sprockets on shaft rotate against a card to make sound.

3C30 Intensity and Attenuation


3C40 Architectural Acoustics


3C50 Wave Analysis and Synthesis


  3C50.10Fourier synthesis.
  3C50.12Casio electronic synthesizer with amp and speaker.

3C55 Music Perception and the Voice


3D Instruments


3D20 Resonance in Strings


  3D20.10Sonometer: Resonant chamber with bowed strings (2).

3D22 Stringed Instruments


3D30 Resonance Cavities


  3D30.35Twirling Tube
  3D30.40Helmholtz Resonators with tuning forks and a candle
  3D30.40Helmholtz resonators drive radiometer vanes, using tuning forks.
  3D30.50Reuben's tube: Standing sound waves in flames along a large pipe.
  3D30.60Kundt's tube: Powder in tube shows standing waves.
  3D30.70Hoot Tube

3D32 Air Column Instruments


  3D32.10Set of eight organ pipes to make a major scale.
  3D32.25Tunable organ pipe.

3D40 Resonance in Plates, Bars, Solids


  3D40.10Xylophone.
  3D40.20Longitudinal wave apparatus: Ball bounces off end of stroked rod.
  3D40.30Chladni's disc: Bowed disk forms patterns in sprinkled salt.
  3D40.31Chladni's Figures: Vibrational modes of a metal plate
  3D40.51Large glass bowl with ping pong balls and violin bow.
  3D40.55Beaker is broken by sound from speaker.

3D46 Tuning Forks


  3D46.15Tuning forks, various.
  3D46.40Giant tuning fork, barely audible, displayed with stroboscope.

3D50 Electronic Instruments


3E Sound Reproduction


3E10 Audio System


3E20 Loudspeakers


3E30 Microphones


3E40 Amplifiers


3E60 Recorders


3E80 Digital System