Wave Motion

PIRA classification 3B

Please note that these tables have not yet been edited to match the equipment that is available within the UW-Madison lecture demo lab. There maybe many items listed within these tables that we either "can not do" or have available.

3B10. Transverse Pulses and Waves

 PIRA # Demonstration Name Subsets Abstract 3B10.01 Klein-Gordon equation wave model A physical realization of the Klein-Gordon equation. Sort of looks like half a bell labs model but the rods hang down out of a horizontal coil spring. 3B10.05 the wave - transverse Have students in the class do the standard stadium wave. 3B10.10 pulse on a rope pira200 Give a heavy piece of stretched rope a quick pulse. 3B10.10 pulse on a rope Create pulses and waves by hand on a long rope stretched across the lecture bench. 3B10.10 pulse on a rope A heavy piece of stretched rope is given a quick pulse. 3B10.10 shake a rope Fix one end of a rope and shake the other. 3B10.10 pulse on a spring Two students stretch a spring and one student hits it to give a transverse pulse. 3B10.10 wave on a rope A long rope is attached to a wall. 3B10.11 slow pulse Epoxy split-shot fishing sinkers on model airplane elastic (1/16" x 3/16") every inch to give a wave speed of about 15 m/sec. 3B10.12 speed of a pulse - stretched string Mount two small pieces of paper on a stretched string so they will interrupt a photocell gate when a pulse from plucking passes by. 3B10.12 speed of a pulse in a rope Microswitches at two ends of a stretcher rope trigger a timer as a pulse passes. Weights are used at one end to vary the tension. 3B10.13 pulse speed on a string A pulse on a steel string passes between two magnets and an oscilloscope is used to measure the time between voltage peaks due to the passing pulse. 3B10.15 rope Use pairs of ropes or tubes to compare speed of pulses as tension and mass per unit length are changed. 3B10.15 tension dependence of wave speed Hold a rubber tube under different tensions and send a pulse along it. 3B10.16 speed of torsional waves 3B10.16 wave speed Show the difference in wave speed and pulse shape on Shive machines with long and short rods. 3B10.17 speed of a slinky pulse Critically damp one end of a stretched slinky by hooking over a steel bar. Measure mass per unit length, time a pulse, etc. 3B10.18 speed of pulses on ropes Pluck two ropes of different mass per unit length, each under the same tension, and compare the speed of the pulses. 3B10.19 chain Transverse pulses and waves are demonstrated on a tilted board. ALSO - hanging slinky. 3B10.20 slinky on the table Create pulses and waves by hand on a slinky stretched down the lecture bench. 3B10.20 slinky on the table A transverse pulse is sent down a slinky on the table. 3B10.25 standing pulse A pulse in a loaded rubber tube driven by a motorized pulley remains almost stationary. 3B10.25 standing pulse An endless belt running at constant speed over two pulleys is struck with a sharp blow and the pulse is nearly stationary. Picture. Reference AJP 16(4)248; Sutton p.139. 3B10.25 stationary pulse A 12' loop of bead chain is suspended over and driven by a large motorized pulley. Ball bearing rollers deform the chain and the pulse moves slowly. 3B10.25 stopping a pulse Run a belt over a pulley at a high enough speed so a wave traveling along it appears to stand still. 3B10.25 stationary transverse wave An endless belt running over two pulleys. Reference: AJP 16(4),248. 3B10.25 pulse on moving chain A motor drives a large loop of chain suspended between horizontal pulleys. 3B10.26 stopping a pulse Suspend a heavy cord formed into a circle from strings below a rotating disc. Spin at speed sufficient that a pulse will appear stationary. 3B10.30 Shive (Bell Labs) wave model pira200 Excite a horizontal torsional wave machine by hand. The other end is open, clamped, or critically damped. 3B10.30 Bell Labs wave machine Bell Telephone Company wave machine - source of film, booklet, and apparatus (as of 1963). 3B10.30 Bell Labs model A long article on the Bell Labs torsional wave model. 3B10.30 torsional waves Show a torsional wave on a Shive wave machine. 3B10.31 toothpick wave machine A method of looping No. 32 rubber bands through toothpicks to make a traveling wave machine. 3B10.31 horizontal torsion bars Use soda straws and seamless elastic to make an inexpensive bell wave motion machine. 3B10.31 horizontal torsion bars Wood dowels are mounted to a section of steel tape. 3B10.32 traveling wave A torsion wave machine hangs from the ceiling. Also, a rope from the ceiling. 3B10.40 Kelvin wave machine A ladder style hanging wave apparatus with strings for the two sides. 3B10.41 stationary pulse - lariat A variable speed motor driven brass chain lariat is struck with a stick and the pulse is stationary at all speeds. simpler version also shown. Diagram and construction details. 3B10.41 hanging torsional waves A vertical torsion wave machine made with electrical terminal clips on a rubber tape. Pictures. 3B10.45 damped Kelvin wave machine A long steel band with metal crossbars carrying balls on the ends is suspended from a copper disc between the poles of an electromagnet. 3B10.50 vertical rods wave model A wave template is slid under an array of vertical rods. 3B10.51 transverse wave machine A cheap modern version of a nineteenth century wave machine with vertical rods driven from the bottom by an eccentric. 3B10.51 vertical rods wave model The bottoms of a series of identical rods rest on a series of discs mounted eccentrically on a common shaft. The tops of the rods execute a wave when the shaft is rotated. 3B10.53 wave generator Picture of a series of balls at different phase angles that seem to be connected to rotating rods. Demonstrates both transverse and longitudinal waves. 3B10.55 transverse waves on the overhead Four demos: a rotating coil, wave templates, a sinusoidal wave plotter, and a superposition wave adder. 3B10.56 project rotating wire A wire spiral is rotated by a motor and projected to demonstrate transverse waves. Construction details. 3B10.60 water waves Water waves in a long trough with glass sides. Put a cork in to show particle motion. Show standing waves with proper timing. 3B10.65 traveling wave on a scope Show a traveling wave near 60 Hz on a line triggered scope and switch to internal triggering to stop the wave, then hold a slit in front of the traveling wave. 3B10.70 pendulum waves A row of rods with balls on the ends are hung from pivots that can swing either in the plane of the row or perpendicular to it. Adjustable collars permit varied coupling. Read it. 3B10.75 uncoupled pendulum waves A set of pendula, started in phase, exhibit a sequence of traveling waves, standing waves, and random motion. Each in the set of successively shorter pendula executes one additional oscillation in the same time interval. 3B10.75 pendulum waves The apparatus from AJP 59(2),186. 3B10.80 solitons in a wave tank A 5.5 m wave tank is described along with analysis. 3B10.85 non-recurrent wavefronts See Mechanical Universe #18 ch 3-5, film loop Ealing #217.

3B20. Longitudinal Pulses and Waves

 PIRA # Demonstration Name Subsets Abstract 3B20.05 the wave - longitudinal Not the standard stadium wave. The students bump into each other to propagate the wave. 3B20.10 hanging slinky pira200 A long slinky is supported on bifilar suspension every four inches. 3B20.10 hanging slinky Compression pulses are sent along a hanging slinky. 3B20.10 hanging slinky Time a longitudinal pulse and compare to calculated. ALSO normal mode. 3B20.10 hanging slinky A long helical spring suspended every few turns with a bifilar suspension. Directions for making the spring. 3B20.10 longitudinal slinky waves Show longitudinal waves on a bifilar suspended slinky with paper flags every fifth coil. 3B20.11 stretched slinky Students stretch a slinky and send longitudinal waves down from one end. 3B20.12 wave cutoff with a hanging slinky Waves do not propagate below a critical frequency if the slinky is supported by short strings. 3B20.13 storing slinky Store a slinky around a #6 dry cell. 3B20.20 longitudinal wave on the air track A pulse is sent down a set of gliders coupled with springs on the air track. 3B20.21 traveling & standing waves/air track Complete discussion of traveling and standing waves on an air track with the critical point being the special mass and damping necessary for the last glider in the traveling case. 3B20.25 air tube magnetic waves An air tube support magnetically coupled beads for demonstrating longitudinal waves. Replacing half the beads with larger mass demonstrates a different medium. 3B20.30 springy snow fence The Pasco longitudinal wave machine has vertical rods pivoted at the center and coupled with springs. 3B20.30 longitudinal wave model The Pasco device. 3B20.35 longitudinal wave machine 3B20.40 ball and spring waves A series of croquet balls are hung from bifilar suspensions and connected with coil springs. Balls of different mass can be used. 3B20.45 hanging magnets About twenty magnets on bifilar suspension are used to show longitudinal waves. 3B20.50 hear the reflection Stretch a stiff helical spring across the room to a sounding board and listen as a longitudinal pulse strikes. 3B20.60 speed of particles, waves A line of sticks with small gaps is pushed from one end. 3B20.70 Crova's disc Non-concentric circles ruled into a plexiglass disc appear to be compressions when projected through a slit. 3B20.70 Crova's Disc A projection Crova's disc.

3B22. Standing Waves

 PIRA # Demonstration Name Subsets Abstract 3B22.10 pira200 A DC motor is driven at variable speeds to generate standing waves on an attached rope. 3B22.11 Melde's driver Bend the clapper away from the magnet of a 110 V ac buzzer. 3B22.11 Melde's driver Use a dc to ac vibrator-converter for generating ac power from batteries to drive the string. 3B22.11 driving mechanism for Melde's A quiet double solenoid driver for Melde's operates at line frequency. 3B22.11 speaker driven string Couple a loudspeaker cone to a string for a variable driver. Use two drivers to show beats. 3B22.11 Melde's driver for OH projector A quiet electromagnetically driven string driver suitable for use on the overhead projector. 3B22.11 Melde's with fluorescent light On the colors seen with fluorescent light illumination. 3B22.11 hair cutter driver A hair cutter powered with a variance is modified to drive a string. 3B22.11 Melde's A Melde's driver. Reference: AJP 20(5),310. 3B22.12 Melde's - tuning fork A tuning fork drives a string into resonances with varied tension. 3B22.12 Melde's - tuning fork Vary the tension of yarn driven by an electrically driven tuning fork. 3B22.12 tuning fork Melde's An electrically driven tuning fork sets up standing transverse waves in a string. 3B22.13 piano wire A motor driven, variable frequency oscillator gives transverse impulses to a stretched piano wire. 3B22.14 electromagnetically excited wire An electromagnet is placed at the center of a stretched wire and connected to a signal generator to produce several modes of oscillations. 3B22.14 AC driven wire The tension is changed on a wire carrying AC in the field of a magnet and the fundamental and various harmonics are shown. 3B22.14 wire standing waves Use iron wire and an electromagnet or AC current and a magnet to generate standing waves in wire. 3B22.15 three tensions standing waves 3B22.15 rubber tube standing waves A long rubber tube driven by a variable speed motor. 3B22.16 phase changes in Melde's Show two positions of max amplitude, one red and one blue, with fluorescent lighting and a vibrator synchronous to the lamp flutter. 3B22.17 mutiple Melde's The same motor drives two horizontal strings and one vertical string of equal length. All strings are in resonance. 3B22.18 AC heated stretched nichrome wire Standing waves are produced by stretching nichrome wire and heating with AC. 3B22.21 air driven rubber tube Standing waves are produced in a stretched rubber tube by a jet of air. 3B22.22 nice wave machine A weighted rubber tube is hung horizontally from the ends of short pivoted and counterweighted bars. Friction adjustments at the pivots allow any amount of energy to be absorbed. When driven from one end, many wave properties may be shown. 3B22.25 stroboscopic projection with wire Waves in a wire are stroboscopically projected. 3B22.25 projecting a standing wave on a wire A rotating mirror arrangement projects the shape of a standing wave on a wire. 3B22.30 Shive /Bell Labs standing waves 3B22.30 Bell Labs standing waves Excite the Bell Labs machine at various rates to obtain standing waves with one, two, and three nodes. 3B22.30 standing waves Drive the Shive wave machine by hand to produce standing waves. 3B22.40 vertical vibrating bar Vibrate a yardstick or meterstick by hand through the fundamental and first overtone. Due to the rule, the position of the node can be measured easily. 3B22.40 transverse waves in a rod Hold a long rod at the center or at an end and vibrate it at the natural frequency with the other hand. ALSO - chalk squeak and breaking. 3B22.41 vertical steel bar Melde's A vertical steel bar is clamped vertically and driven mechanically through the first three harmonics. 3B22.45 free boundary hanging tube A support designed to excite a hanging tube while maintaining free boundary conditions. 3B22.50 slinky standing waves Drive a hanging slinky by hand to produce standing waves. 3B22.51 hanging spring standing waves A solenoid drives a magnet attached to a hanging spring. 3B22.51 hanging slinky standing waves A motor oscillator drives a hanging slinky. 3B22.52 driven jolly balance spring waves A tuning fork drives a jolly balance spring to produce standing longitudinal waves. A lantern projector with a rotating disk slows the motion stroboscopically. 3B22.60 longitudinal standing waves Excite the Pasco longitudinal waves machine to get standing waves. 3B22.65 magnetostrictive standing waves A feedback circuit to a coil around a nickel rod drives magnetostrictive standing waves indicated by a ball bouncing at one end. 3B22.70 soap film standing waves/oscillations Large wire frames dipped in soap film are manipulated by hand to produce standing waves. Nice pictures. 3B22.75 standing waves Use a sensitive flame to detect standing waves from a loudspeaker between two boards. 3B22.90 traveling and standing wave models A projection device that gives the appearance of waves traveling in opposite directions and the sum of the waves. 3B22.90 crank wave model Wire helixes turned about their axes in a lantern projector appear as waves traveling in opposite directions. An additional bent wire shows the resulting standing wave. 3B22.99 analog computer simulation An analog computer used with a dual trace storage scope to demonstrate traveling and standing waves.

3B25. Impedance and Dispersion

 PIRA # Demonstration Name Subsets Abstract 3B25.10 impedance matching - Shive model 3B25.10 impedence matching - Bell model Two sections of a horizontal torsion machine with different lengths are joined abruptly for unmatched coupling and with a section of gradually lengthening rods for matched coupling. 3B25.10 wave reflection at a discontinuity Two Bell Labs torsion machines with different length rods are hooked together. 3B25.10 wave coupling Shive wave machines with long and short rods are coupled abruptly or with a tapered section. 3B25.15 impedence mismatching in rope Pulses are sent down a cord with part of its length half the diameter of the other part. 3B25.20 reflection - Shive model 3B25.20 reflection - Bell labs 3B25.20 reflection of waves A pulse sent down a Shive wave machine reflects from either a fixed or free end. 3B25.25 spring wave reflection Reflections from a long horizontal brass spring with fixed and free ends. 3B25.26 fixed and free rope reflection Tie a rope to a bar with a loose knot or tie it to a clamp. 3B25.30 dispersion in a plucked wire A crystal phonograph cartridge attached to one end of a long stretched wire will pick up the reflected waves when plucked. 3B25.35 acoustic coupling with speaker 3B25.35 acoustic coupling Sound a 2" loudspeaker alone and with an exponential horn. 3B25.40 soundboard 3B25.50 dispersion in a plucked wire 3B25.51 slinky-whistler dispersion An analysis of and directions for performing the slinky-whistler dispersion. 3B25.55 dispersion A long helical coil of fine wire transmits sound slowly. Speak into a sound box on one end and somewhat distorted sound emerges. 3B25.62 echoes in a pipe A 10" dia 85' tube yields five clearly discernible echoes. 3B25.65 chirped handclaps Clap your hands while standing next to a corrugated wall. 3B25.65 racquetball court whistlers Whistlers rise in frequency in the racquetball court. 3B25.66 chirp radar Modify a simple microwave Doppler shift apparatus to study chirp concepts. 3B25.66 dechirping slinky whistlers Record a single whistler on the Mac, play it backwards into the whistler-phone, and hear a "ch". 3B25.67 comment on "culvert whistlers" A comment clarifies the relationship between culvert whistlers and ionospheric whistlers. 3B25.67 culvert whistlers revisited An analysis of "echo tube" corridor demonstrations that also deals with ionospheric whistlers, tweeks and chirped handclaps. 3B25.67 culvert whistlers Long article on culvert whistlers. 3B25.80 shear, Lamb, and Rayleigh waves A panametrics 5022 P/R pulser/receiver driving a piezoelectric transducer in a water bath directed at solid blocks is used with an oscilloscope to show traces of different waves.

3B27. Compound Waves

 PIRA # Demonstration Name Subsets Abstract 3B27.10 slinky and soda cans Persons at each end of a stretched slinky generate a pulse. The addition of the pulses kicks one soda can out from a line of cans placed along the slinky. Also cancel opposite pulses. 3B27.15 wave superposition Start positive pulses from each end of a Shive wave machine. 3B27.20 adding waves apparatus A framework allows brass tubes representing two sine waves to be combined point by point to give the resultant. Projected on the overhead. 3B27.21 harmonic sliders A template with a sine wave shape is slid under a set of vertical wood bars cut to various lengths to forming a different sine waves. 3B27.21 adding waves A machine with pins cut to form a sine wave riding on a plate machined to a sine wave. Picture. Construction details in appendix, p. 635. 3B27.21 wave addition model Stack several sets of vertical rods that describe sine waves to show the resultant. 3B27.22 carousel waves 630 knitting needles are mounted on a bicycle wheel riding on a second coaxial bicycle wheel with a sine wave cam. Pictures. Construction details in appendix, p. 639. 3B27.23 wood block interference A framework holds wood blocks cut to length to form a sine wave. A template in the shape of another wave is pushed against the bottom of the blocks. 3B27.30 beat pendula Two physical pendula with slightly different periods oscillate in parallel planes and the sum is shown by reflecting a laser beam off mounted mirrors. 3B27.30 sand pendulum compound wave A compound sand pendulum with both oscillations in the same plane dumps onto an endless belt. 3B27.31 beat pendula Three mirrors are mounted on two pendula of slightly different frequencies. Two show the motion of each pendulum and one shows the combination. Pictures, Diagram. Construction details in appendix, p. 625. 3B27.32 recording beat pendula Inductive pickup of the position of two pendula of slightly different frequencies. Construction details. 3B27.33 photo of beat pendula Lenses on beat pendula focus spots of light on moving photographic paper. 3B27.35 turntable oscillators A phono turntable drives a horizontal platform in SHM, and two can demonstrate beats and Lissajous figures. 3B27.40 beats Light is reflected off mirrors on two slightly different tuning forks to a rotating mirror and onto a screen. 3B27.45 beat lights The output of an audio oscillator is added to line frequency through a step-up transformer with 15W lamps as indicators.

3B30. Wave Properties of Sound

 PIRA # Demonstration Name Subsets Abstract 3B30.55 temp and speed of sound Two whistles of the same pitch are blown and one is then heated with a match. 3B30.55 sound velocity at different temperatures Blow two identical organ pipes from the same source, then heat the air going to one of the pipes with a Bunsen burner. 3B30.56 velocity of sound with temperature Attach a whistle to a coil of copper tubing placed in liquid nitrogen. 3B30.60 speed of sound in rod and air Hit a twelve foot aluminum rod on one end with a hammer. Trigger an oscilloscope with a microphone at the hammer end display the signal from microphones at the end of the rod and at the same distance. 3B30.61 velocity of sound in a rod A timer is triggered by metal balls bouncing off brass blocks mounted one meter apart on a brass rod when one end of the rod is struck with a hammer. 3B30.62 direct speed of sound in a rod A bell clapper hits one end of a rod and triggers an oscilloscope, a phonograph needle and crystal pickup on the other end generates a signal that is displayed on the scope. 3B30.65 music box Sound is transmitted through a long wood rod from a music box in the basement to a sounding box in the classroom. 3B30.65 transmission of sound through wood A long 1"x1" wood bar is placed on top of a music box in the basement, through a hole in the floor, to a sounding box in the classroom. 3B30.66 medium and speed of sound Stand near a railroad track and listen as a hammer is struck against the rail 200' away.

3B33. Phase and Group Velocity

 PIRA # Demonstration Name Subsets Abstract 3B33.10 group velocity on scope Two sine waves of almost equal frequencies and their sum are displayed on a oscilloscope. 3B33.10 wave and group velocity on scope Directions for showing wave and group velocities on the oscilloscope. 3B33.10 phase and group velocity This article spells out the subtleties for getting both traces to move in one direction. 3B33.10 phase and group velocity An oscilloscope shows signals from two oscillators and the sum. 3B33.10 group and phase velocity Two sine waves are added and displayed on an oscilloscope. Picture, Diagram. 3B33.11 group velocity Measuring group velocity using two sine waves and an oscilloscope. Diagram. 3B33.12 group velocity - gated pulse An amplifier circuit is given that gates a sine wave generator with a square wave generator. The resulting packets of sine waves are found to be superior to the beat method. 3B33.18 group and phase vel.- apple peeler This group and phase velocity device was made from an apple peeler. 3B33.20 two combs Superimpose two combs on the overhead projector to show phase and group velocity. 3B33.20 two combs This was published in AJP,21,388 (1953). 3B33.20 two combs Move two combs across each other on an overhead projector to demonstrate phase and group velocity. Picture. 3B33.21 phase and group velocity with bars Two sheets of bars of ratio 9:10 are superimposed on the overhead projector. A revolving model works too. 3B33.22 densimeter comb Two densimeter plates are used in place of combs. Pictures. 3B33.25 phase and group velocity on the OH A sheet with black bands is pulled across an overhead projector covered except for slits parallel, perpendicular, and at 45 degrees to the motion. Picture, diagram, construction details in appendix, p. 635. 3B33.30 R H Good software Free Apple II software showing, among other things, group and wave velocity. This is the best Apple II software ever written. 3B33.31 group velocity software A short review of group velocity that happens to mention some software. 3B33.40 group and phase velocity in a pool Make a large scale demonstration in a fountain pool (14' x 25' x 1').

3B35. Reflection and Refraction (sound)

 PIRA # Demonstration Name Subsets Abstract 3B35.10 gas lens Hydrogen and carbon dioxide balloons are used as diverging and converging lenses. Picture. 3B35.10 refraction lens - CO2 Make an acoustical lens by cementing the edges of two circular sheets of cellophane and filling the space between with CO2. 3B35.20 refraction prism - CO2 Direct a beam of sound through a prism of CO2. 3B35.22 refraction with CO2 Set up a source, reflector, and detector. Then pour CO2 into the path of the incident beam to scatter the sound. 3B35.30 parabolic reflector and sound source 3B35.30 curved reflectors Place a watch at the focal point of a mirror and project the beam around the class. 3B35.35 directional transmission A Galton whistle at the focus of a parabolic mirror produces a beam detected by a microphone placed at the focus of a second parabolic mirror. 3B35.36 curved reflectors Place a whistle and sensitive flame several meters apart, then place a parabolic reflector behind the whistle. 3B35.37 reflection of sound waves A whistle and detector are placed in a line parallel with a reflector. Precautions may have to be taken to insure directionality of the sound waves. 3B35.39 curved reflectors Take a field trip a dome to observe the "whispering gallery" effect. 3B35.50 wave properties of sound Using a shrill whistle of wavelength from 2-8 cm, many properties of waves usually shown only with optics can be demonstrated. Many diagrams. 3B35.60 refraction of water waves Plane waves refract in a tank with deep and shallow sections.

3B39. Transfer of Energy in Waves

 PIRA # Demonstration Name Subsets Abstract 3B39.10 water wave model A row of short rods mounted on the side of a box rotate at the same rate with equal phase shift between successive rods. The combined motion simulates a traveling water wave. 3B39.10 water wave model showing phase vel. Balls that rotate vertically on the end of rods hooked to horizontal shafts and are coupled together with a regular phase difference. 3B39.12 water wave model A set of 28 rotating arms driven in circular motion with constant successive phase difference. Pictures. Construction details in appendix, p.644. 3B39.14 rotating phasors Synchronous motors drive a set of balls in a circle with phase relationship such that the balls describe a sine wave. 3B39.20 dominoes 3B39.30 multiple wave types A machine demonstrates transverse, longitudinal, and water wave motion. Picture. Construction details in Appendix, p.636. 3B39.52 seismograph The output from seismographs are shown on an oscilloscope.

3B40. Doppler Effect

 PIRA # Demonstration Name Subsets Abstract 3B40.10 pira200 A battery powered buzzer on a string is swung around in a horizontal circle. 3B40.11 doppler speaker on turntable A battery operated oscillator drives a speaker mounted on a 3' turntable. 3B40.11 doppler effect Mount two speakers on a rotating frame and attach to an audio oscillator through slip rings. 3B40.13 intermittent doppler speaker A rotating speaker is switched on and off so sound is emitted only when the speaker is moving towards or away from the observer and arranged so the cone of sound is directed at the observer only. Reference: AJP 21(5)407. 3B40.15 doppler whistle A whistle on the end of a tube is blown while swung around in a horizontal circle. 3B40.15 doppler whistle A small whistle at the end of a rubber tube is twirled around the head while being blown. 3B40.15 doppler whistle A compressed air whistle on the end of a rubber tube is twirled around the head. 3B40.16 doppler rocket A whistling rocket mounted on a rod is rotated in a three foot radius circle. 3B40.18 doppler effect A moving tuning fork, rotating reed, rotating whistle, and rotating speaker all show the Doppler effect. 3B40.20 doppler spear Stroke a twelve foot aluminum rod until it sings, then hold it at the midpoint and thrust it toward the class. 3B40.25 An adjustable speed motor rotates an arm with a reed at the end. 3B40.30 doppler beats A naked tuning fork is moved back and forth in front of a wall; a poster board is moved back and forth behind a fork. Reference: AJP 10(2),120. 3B40.30 doppler beats The complete discussion of Doppler beats: swinging tuning forks and speakers of equal or unequal frequencies, moving reflector. Diagrams. 3B40.32 doppler radio on air track Modulate an rf generator and tune two transistor radios to the frequency. Mount one on an air track and listen to the beats with the stationary radio. 3B40.33 moving detector doppler A moving microphone detector is tuned to the Doppler shifted frequency of a loudspeaker. 3B40.35 doppler speakers The difference tone between a stationary speaker and a pendulum speaker is amplified through a third speaker. Diagrams. Reference: AJP 12(1),23. 3B40.50 doppler effect analog A student drops paper riders on an endless string over two pulleys and the instructor picks them up while walking toward the student.

3B45. Shock Waves

 PIRA # Demonstration Name Subsets Abstract 3B45.10 ripple tank film loops A 3:45 film loop shows doppler effect and shock waves. 3B45.10 ripple tank film loop - shock waves The film loop lasts 3:45. 3B45.11 continuous ripple-tank doppler A loudspeaker wave generator is used with a large slowly turning disk of water for continuous generation of Doppler and shock waves. Only the small portion of the disk of interest is illuminated at one time. 3B45.13 shock wave in water A film of water flowing down an incline is interrupted by a point producing waves. 3B45.15 shock waves in ripple tank 3B45.15 ripple tank doppler and bow shock Mount a burette on a carriage over a large pan of water. 3B45.20 pop the champagne cork Pop a plastic cork out of a water filled champagne bottle by hitting the base on a pine board. 3B45.30 solition tank 3B45.31 nonpropagating hydrodynamic solitons Theory and apparatus for producing solitons of (0,1) and (0,2) modes are discussed. 3B45.35 water trough tidal bore Water in a long tank is given a sudden impulse with a paddle and a shock wave is produced. 3B45.40 tsunami tank A simple sloping tank with ground glass side for recording the peak profile. 3B45.60 supersonic jet Schleirin optics are used to project the flow of a supersonic jet. 3B45.65 shock waves in argon An elaborate setup to introduce helium into a low pressure argon tube and cause a yellow glow from the compressed argon.

3B50. Interference and Diffraction

 PIRA # Demonstration Name Subsets Abstract 3B50.10 ripple tank - single slit The film loop lasts 3:30. 3B50.10 ripple tank - single slit Diffraction from a plane wave passing through a single slit on the ripple tank. 3B50.10 single slit diffraction of water wav Ripple tank single slit diffraction with varying slit and wavelength. 3B50.12 ripple tank diffraction Use the ripple tank to show radiation patterns from different baffle, pipe, and horn configurations. 3B50.20 ripple tank - two point Two point sources show interference. A plane wave through a slit shows diffraction. 3B50.20 ripple tank - double source A ripple tank with two point sources in phase. 3B50.20 ripple tank - two point Waves produced by audio oscillators drive beads attached to earphone diaphragms. Picture. More. 3B50.25 ripple tank - double slit Interference from a plane wave passing through a double slit in the ripple tank. 3B50.25 double slit interference of water wa Ripple tank double slit interference with varying wavelength and slit separation. 3B50.28 mechanical double slit Lead shot drops from two hoppers and shows a single distribution with no interference pattern. 3B50.30 ripple tank - film loops 3B50.40 Moire pattern transparencies pira200 A double slit representation of Moire patterns from two sheets of semicircular ruled transparencies. 3B50.40 Morie pattern transparencies Transparencies with identical circular patterns are placed on top of each other with a slight offset. 3B50.40 Moire pattern Moire patterns from two sheets of semicircular ruled transparencies form a double slit representation. 3B50.40 Moire pattern Two transparencies of equally spaced circles on the overhead. 3B50.42 Morie pattern - complete treatment All you ever wanted to know about Morie patterns. 3B50.43 Moire' pattern Electronic chassis covers (with holes kind) are mounted several inches apart and the pattern changes as your viewing distance changes. 3B50.43 Moire pattern Moire patterns with chassis boxes. Pictures. 3B50.50 double slit transparency Two strips of clear acetate with identical sine waves are pivoted from two points representing two slits to demonstrate constructive and destructive interference. 3B50.51 two ropes Two ropes mounted on the wall 3' apart and painted with 6" black and white sections are stretched and crossed by the demonstrator to simulate constructive or destructive interference. 3B50.55 interference model Painted wave trains on wood lath are attached to magnets for use on a steel blackboard 3B50.80 ripple tank scattering A brass disc is used as an obstacle for various wavelength plane waves to show scattering.

3B55. Interference and Diffraction of Sound

 PIRA # Demonstration Name Subsets Abstract 3B55.10 pira200 Two speakers driven from a common source are mounted at the ends of a 1 m rotatable bar. 3B55.11 interference Investigate the diffraction pattern from two rectangular aperture megaphones hooked to the same source. 3B55.12 speaker bar, etc. A set of interference from two coherent sources demonstrations: slides, ripple tank, speaker bar, microwave, homemade handout optics double slits. 3B55.13 interference Send a parallel beam against a board with two slits and investigate the result with a sensitive flame. 3B55.14 speaker bar room acoustics problems The effects of reflections from the room surfaces are often underestimated. 3B55.15 speakers on a bar Mount twelve 3" diameter speakers on a bar with a 25' radius. 3B55.30 baffle and speaker Hold up a 1" speaker oscillating at 350 Hz, then add a baffle in front of the speaker. 3B55.30 baffle and speaker Play a small speaker with a tape player. Intensity increases with the addition of a baffle with speaker cone size hole. 3B55.31 baffles and resonators A baffle is held between the forks of a tuning fork on a resonator box with the open end facing toward and away from the class. 3B55.31 interference of a tuning fork Hold a tuning fork in the hand with and without a cardboard baffle. 3B55.40 trombone / Quinckes' tube pira200 A speaker drives two tubes, one variable , that come together into a common horn. 3B55.40 trombone A horn driver is connected to tubing that splits into two variable path lengths and is recombined at a horn. 3B55.40 trombone Two identical trombone slide assemblies are connected in parallel between a driver and detector. One of the slides is lengthened to produce a path length difference of one half wavelength. 3B55.40 trombone Two "U" tubes , one of them of variable length, are both connected to the same source and ear piece. 3B55.41 large trombone interference A large trombone interferometer made out of 1' copper tubing. 3B55.42 Herschel divided tube Interference of sound in a double tube, one side of variable length. Made of Plexiglas. 3B55.45 Acoustical Interferometer A speaker is mounted at one end of telescoping plastic tubes, and a microphone is mounted at one end of the inner tube. 3B55.51 diffraction A board with a variable slit is placed in a parallel sound beam. The detector is moved about and the slit width is varied. 3B55.51 diffraction A whistle and parabolic mirror form a parallel beam. Interrupt the beam with a barrier and move the detector back until it responds again. Or - use successively smaller barriers until the detector responds but is still in the shadow of the barrier. 3B55.55 diffraction pattern of a piston A speaker cone is removed and replaced with a Lucite disc. The intensity is measured with a microphone as the speaker assembly is rotated. 3B55.55 diffraction Attach a megaphone of rectangular cross section 3/2 wavelength by wavelength/3 to a whistle. A detector off to the side is placed so it will respond only when the long dimension is vertical. 3B55.58 hearing around a corner Things aren't simple, seeing and hearing are different. 3B55.60 diffraction fence 3B55.60 diffraction of sound The beam from a Galton whistle at the focus of a parabolic mirror is passed through a picket fence to a detector. 3B55.60 diffraction with a wire mesh Parabolic reflectors are used to produce parallel sound waves that are directed through an audio diffraction grating to a movable microphone. 3B55.80 diffraction of coherent and incoherent Plot the intensity vs. angle of four speakers driven by four oscillators and by a single oscillator. 3B55.90 Lecture Demo Guy At the drop of a hat, Lecture Demo Guy will appear and interfere with the task at hand. 3B55.91 diffraction by ultrasound in liquid The physical origin of the "shadow" seen in the visual display of standing wavefronts in liquids. 3B55.92 ultrasound camera A description with construction details of a ultrasonic camera for demonstrating real image formation and Fraunhofer and Fresnel diffraction. Pictures and Diagrams.

3B60. Beats

 PIRA # Demonstration Name Subsets Abstract 3B60.10 Two tuning forks differing in frequency by about 1 Hz are mounted on resonance boxes and set to vibrate together creating beats. A microphone and oscilloscope can be used to display the resultant waveform. 3B60.11 beat bars Two identical bars mounted on resonator boxes are detuned by a movable weight on one. listen to the beats and show on an oscilloscope. 3B60.11 beat bars The standard tunable bars on a resonance box. 3B60.15 Two tunable organ pipes of similar frequency are played simultaneously creating beats. 3B60.16 Kipp singing tubes beats Two Kipp singing tubes are tuned to produce beats. 3B60.17 Galton whistle beats Two Galton whistles can be adjusted to produce "dog beats". 3B60.20 beats on scope pira200 Two audio transformers are fed thru an audio interstage transformer to an oscilloscope and audio amp. 3B60.20 beats on scope Dual function generators are used to generate a beat pattern that can be amplified and listened to and/or displayed on a scope. 3B60.20 beats on scope The output of two audio transformers is fed into the secondary of an audio interstage transformer and from there to both an oscilloscope and an audio output transformer. 3B60.20 beats on scope An interstage audio transformer and an audio output transformer couple two oscillators to an oscilloscope and speaker. 3B60.20 beats with speaker and oscilloscope Two function generators are used to make beats that are displayed on a scope and amplified to a speaker. 3B60.22 beat oscillator switch A circuit to switch between inputs or the sum of the inputs to allow either the individual frequencies or the beats to be heard. 3B60.30 beats vs. diff.tone see 3C55.35 3B60.31 reply to beats misconceptions Beat notes are what the misconceptions are about, beats are just combined frequencies. 3B60.31 beats vs. difference tones Hey, guys, simple "mixture" of frequencies gives difference tones. Beats are only present when modulation operations are used. 3B60.38 beat demodulation Two oscillators drive a loudspeaker, switch a diode into the circuit and the modulation frequency can be detected. 3B60.40 ripple tank beats Two point sources in a ripple tank run at different frequencies. Theory included. 3B60.40 ripple tank beats Beats are demonstrated as a moving interference pattern in the ripple tank by using two separate point source generators with variable frequency controls.

3B70. Coupled Resonators

 PIRA # Demonstration Name Subsets Abstract 3B70.10 coupled tuning forks Two matched tuning forks are mounted on resonance boxes. Hit one and the other vibrates too. 3B70.10 resonance in forks Two identical tuning forks on resonance boxes - strike one and the other starts vibrating. 3B70.10 sympathetic vibrations Two tuning forks on resonance boxes: hit one and the other vibrates too. Several hints on showing this effect. 3B70.20 coupled speaker/tuning forks Drive a tuning fork on a resonant box with a speaker. 3B70.25 sympathetic vibrations in forks A horn driver directed at a box coupled to a tuning fork produces sympathetic vibrations which are detected by a crystal pickup and shown on an oscilloscope.

fw: WaveMotion (last edited 2018-07-18 18:47:14 by srnarf)