sound

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Boomwhackers

boomwhackers

  • Length of each tube determines tube’s resonance pitch. The longer the tube the lower the pitch. Tone produced by whacking a tube reveals its note of resonance. Resonance pitch can be changed by attaching the plastic end-cap.
  • For additional demo ideas and see: boomwhackers
  • Located in L02, section C2.
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Temperature and Sound

Sound and Temperature Pipes

Copper pipes chime when hit (hang by loop and tap with hard object). Pipes are identical in size and composition, and are therefore identical in pitch.

To see how temperature affects pitch, dip one pipe in liquid nitrogen and cool for 1 minute. Tap both pipes to hear differences in pitch. Caution: DO NOT TOUCH COLD PIPE WITH BARE HANDS. USE CRYO GLOVES. 

Pipes located in L02, section C-1. Ask for assistance with LN2.

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Sound of g

sound of g 1

sound of g 3

sound of g 2

  • Nuts are tied to two separate ropes. Spacing between nuts on rope 1 is constant; spacing between nuts on rope 2 goes as the square of the distance from the end of the rope.
  • Hang ropes vertically and drop onto wooden platform. When rope 1 falls sound made by nuts (hitting board) increases in frequency, indicating acceleration of rope. When rope 2 falls, the nut-hitting-board sound is periodic, due to r^2 spacing.
  • Note: When hanging string, first nut (on bottom of string) rests upon board. So first nut does not fall- merely used as an a position anchor.
  • Located in L02, section B3.

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Dog Whistle

 

Dog Whistle Demo Picture

  • Determine the highest frequency of audible sound. Adjustable
    whistle produces mostly frequencies inaudible to us. Lowering the pitch brings
    the sound into most people’s audible range.
  • Located in L02,

 

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Resonance Tube

 

Resonance Tube Demo Picture

  • Purpose: Demonstrate resonance and measure speed of sound.
  • Two different resonance tubes are shown above.

For Smaller Tube

  • Strike tuning fork on rubber pad; place fork near larger
    opening of tube; slide inner tube in and out until resonance is heard. Use
    tube length and frequency to determine speed of sound.

For larger Tube

  • Use speaker and function generator to find resonant frequency
    of tube. Once resonance is found, use vernier microphone to locate nodes and
    anti-nodes.Use tube length and frequency to determine speed of sound.
  • Located in L02,

 

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Beats Demo

beats3

beats2

beats1

  • Listen to beat frequencies through speakers, while simultaneously seeing waves with oscilloscope. Use scope’s math function to add waves together. Resultant wave (shown in red, above) displays beats.
  • Demo consists of 2 function generators, 2 speakers, and one
    oscilloscope.
  • Located in L02, section C2; Oscilloscope located in L35,
    section F4

 

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Doppler Rocket

 

Doppler Rocket Demo Picture

Two people required to use this demo. Each person holds set of handles, and unwinds rope (about 20 m) . When one set of handles is quickly separated (handles initially held together, then quickly pulled apart) the football shaped “rocket” is forced to slide down the ropes. The rocket contains a noise maker (turned on manually) that exhibits Doppler shift when in motion. Users take turns launching and catching the rocket. Doppler affect can be heard by audience members in close proximity.

See: https://www.pasco.com/prodCatalog/WA/WA-9826_doppler-rocket/

  • Located in L02, section C2

 

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Wave on Loop

 

Wave on Loop Demo Picture

Wave on Loop Demo Picture 2

  • This demonstration has been used to explain how sound can
    be used to break a wine glass, or to help illustrate principles behind the
    Bohr model of the hydrogen atom.
  • There are two configurations of loops from which to choose:
    parallel to the floor or perpendicular to the floor.
  • When changing accessories to the oscillator be careful to
    lock the piston (as the oscillator is quite delicate).

Location

  • Mechanical oscillator, wire loop, and
    function generator located in L02, section C2, in “Chladni plates”
    box.