#acl Narf:read,write,delete,revert,admin FacultyGroup:read,write All:read ||<25% style="text-align:center">[[PiraScheme#WavesSound|Table of Waves and Sound]] ||<25% style="text-align:center">[[Acoustics|Waves and Sound(3C): Acoustics]] ||<25% style="text-align:center">[[SoundReproduction|Waves and Sound(3E): Sound Reproduction]] ||<25% style="text-align:center">[[Demonstrations|Lecture Demonstrations]] || == Instruments == ''PIRA classification 3D'' = 3D20. Resonance in Strings = ||<10% style="text-align:center">'''PIRA #''' ||'''Demonstration Name''' ||'''Subsets'''||<60% style="text-align:center">'''Abstract''' || ||3D20.10 ||sonometer || ||A sounding box with strings, tuning machines, and adjustable bridges. || ||3D20.10 ||sonometer || ||A long spruce box with three strings, tuning machines, and adjustable bridges. || ||3D20.11 ||vertical sonometer || ||A vertical sonometer allows tension to be applied by simply hanging weights. || ||3D20.14 ||tuning fork driven sonometer || ||Place a tuning fork on the bridge of a tuned sonometer and observe the motion of a small piece of paper placed on the wire at its center. || ||3D20.15 ||harmonics on a string || ||Pluck a string at different distances from the end or pluck while touching at various nodes. || ||3D20.20 ||modes of string oscillation on scope || || || ||3D20.20 ||modes of string oscillation || ||Use voltages generated by magnets placed across steel strings attached to an oscilloscope to view string motion. || ||3D20.20 ||sonometer || ||An electromagnetic pickup is used to display the waveform of the sonometer string on an oscilloscope. || ||3D20.21 ||guitar and scope || ||Show the output of an electric guitar on an oscilloscope. || ||3D20.30 ||bowed string || ||An overhead projector is modified for strobe projection and the string is bowed with a motorized "O" ring. || ||3D20.30 ||sonometer wire motion || ||Demonstrate the motion of a sonometer wire by stroboscopic shadow projection or using a light beam and revolving mirror. || ||3D20.30 ||string in a projector || ||The motion of a string is shown by placing any portion in a lantern projector limited by a slit. The difference in bowing, plucking, and striking can be demonstrated. || ||3D20.31 ||optical detection of string motion || ||An optical detection system for showing the position of a vibrating string. || ||3D20.35 ||resonance of strings || ||A tuning fork is held against a three string sonometer with one string tuned to the fork frequency. Only the tuned string will vibrate. || ||3D20.36 ||simulated piano string coupling || ||A classroom device that simulates the coupled motion of piano strings and theory of the device. || ||3D20.45 ||longitudinal vibrations in strings || ||Stroke a string attached to a diaphragm across the open end of a cylinder. By jerking, you can make it bark like a dog. || ||3D20.52 ||aeolian harp || ||Mount strings vertically on a rotating table to give the sound of strings excited by the wind. || ||3D20.52 ||aeolian scope || ||A sort of aeolian stethoscope. || ||3D20.60 ||rubber-band harp || ||The pitch of a rubber-band changes only slightly with great increase in length (tension). || = 3D22. Stringed Instruments = ||<10% style="text-align:center">'''PIRA #''' ||'''Demonstration Name''' ||'''Subsets'''||<60% style="text-align:center">'''Abstract''' || ||3D22.10 ||violin || || || ||3D22.20 ||cigar box cello || ||A wooden cigar box serves as sounding box for a one string violin. || ||3D22.20 ||cigar box cello || ||A one string violin made with a cigar box body. || = 3D30. Resonance Cavities = ||<10% style="text-align:center">'''PIRA #''' ||'''Demonstration Name''' ||'''Subsets'''||<60% style="text-align:center">'''Abstract''' || ||3D30.10 ||vertical resonance tube || ||Draw a glass tube out of a water bath while holding a tuning fork over one end. || ||3D30.10 ||veritcal resonance tube || ||The length of a glass tube is varied by pulling it out of a water reservoir. A tuning fork is used as a frequency source. || ||3D30.10 ||vertical resonance tube modification || ||Design of a clamp to hold the tuning fork and resonance tube, and a bracket for the water reservoir. || ||3D30.10 ||vertical resonance tube || ||A glass tube is drawn out of a water bath while holding a tuning fork over one end. || ||3D30.10 ||vertical resonance tube || ||Use a tuning fork to excite the air column in a vertical tube as it is pulled out of a water bath. || ||3D30.11 ||vertical resonance tube || ||Blow across the mouth of bottles or a adjustable air column. || ||3D30.12 ||vertical resonance tube || ||A vertical tube is mounted over a siren disk. || ||3D30.14 ||open tube resonance || ||A length of open tube adjusted by a paper extension and excited by a tuning fork. || ||3D30.15 ||resonance tube with piston || ||Mount a microphone on a piston that slides in a glass tube and close the other end of the tube with a speaker. || ||3D30.16 ||horizontal resonance tube || ||A plunger on a rod is used to change the effective length of a horizontal glass tube as a tuning fork supplies the exciting frequency. || ||3D30.16 ||organ pipe velocity nodes || ||Lower a ring with a membrane and sand into a pipe with a clear side to observe velocity nodes and antinodes. || ||3D30.17 ||modes of a bottle || ||A thorough discussion of modes of various bottles working up to a 3-D model. || ||3D30.19 ||low frequency generator || ||A special tip for an air jet that produces many frequencies of low intensity useful for exciting enclosed air columns. || ||3D30.20 ||open and closed tubes 256/512 || || || ||3D30.20 ||resonance tube 256/512 || ||A tube is cut to length to resonate at 256 Hz when closed and 512 Hz when open. || ||3D30.21 ||conical pipes || ||Corrections for the effective length of open and closed circular pipes are given. A conical pipe discussion with several interesting demonstrations is listed. || ||3D30.35 ||[[Corrugaphone]] || || || ||3D30.35 ||Hummer tube || ||The complete explanation on singing corrugated pipes. || ||3D30.35 ||freq tube dash pot || ||A freq tube is attached to coffee can moved up and down in a pail of water. || ||3D30.35 ||freq tube || ||Open tubes of corrugated plastic are whirled around. || ||3D30.40 ||Helmholtz resonators || ||A set of spherical resonators made of spun brass. || ||3D30.40 ||Helmholtz resonators || ||A small vane is rotated when placed near the small opening of a resonating Helmholtz cavity. || ||3D30.40 ||acoustic resonator || ||This picture appears to be of a Helmholtz resonator. || ||3D30.40 ||Helmholtz resonators || ||Two resonators are matched to two tuning forks. || ||3D30.41 ||tuning a resonance box || ||The hole size of a resonance box is adjusted to maximize resonance with a tuning fork. || ||3D30.43 ||Fizeau resonance box || ||A toothed wheel is used to produce a high pitched sound and an adjustable resonance box with a sensitive flame detector is used to determine speed of sound. || ||3D30.45 ||ploop tubes || ||Stoppers are removed from a set of tubes of varying length. || ||3D30.45 ||ploop tubes || ||Pull stoppers out of test tubes filled with water to different depths. || ||3D30.50 ||Ruben's tube || ||The standard Reuben's tube. || ||3D30.50 ||Ruben's tube || ||A gas filled tube with flames from a row of holes along the top and a speaker at one end. || ||3D30.50 ||Ruben's tube || ||Directions for building a Ruben's tube. Picture, Diagrams. || ||3D30.50 ||Ruben's tube || ||Drill a line of holes along a downspout and drive one end with a loudspeaker and introduce gas in the other. Flames indicate nodes and antinodes. || ||3D30.50 ||Ruben's tube || ||A horn driver is used as a sound source. || ||3D30.55 ||Rubens tube comment || ||A comment on AJP 53,1110 (1985). || ||3D30.55 ||Rubens tube flame structure || ||An examination of the structure of the flames in the normal mode (flame maxima at pressure nodes). || ||3D30.55 ||Ruben's tube nodes || ||The pressure is measured at each flame hole and the results are that the flames are larger at the pressure antinodes. || ||3D30.55 ||Ruben's tube nodes || ||A comment on a note that the tube can be operated with flame maxima at either pressure node or pressure antinode. || ||3D30.60 ||[[KundtsTube|Kundt's Tube]] ||pira200||Sawdust in a tube makes piles when driven by rubbing a rod attached to a disc. || ||3D30.60 ||Kundt's tube || ||Standard Kundt's tube: glass tube with cork dust, stroke a rod to excite air in tube. || ||3D30.60 ||Kundt's tube || ||Stroke a rod to excite cork dust in a tube. || ||3D30.61 ||horn driven Kundt tube || ||Investigation of striations in an electrically driven Kundt tube. || ||3D30.61 ||Kundt's tube || ||The cork dust in Kundt's tube is excited by a horn driver. || ||3D30.62 ||Kundt's tube || ||A variation of Kundt's tube with an organ pipe made with one side of rubber or cellophane and sprinkled with sand while laid on its side. || ||3D30.63 ||Kundt's tube on the overhead || ||A Kundt's tube is modified for use on the overhead projector. || ||3D30.64 ||evacuate Kundt's tube || ||Show the effect of pressure variation on the speed of sound by partially evacuating the Kundt's tube. || ||3D30.65 ||hot wire Kundt's tube || ||Cooling of a glowing wire down the center of a tube indicates standing waves. || ||3D30.65 ||horizontal resonance tube - wire || ||A nichrome wire stretched down the middle of a glass tube and heated electrically will glow to show standing waves. || ||3D30.65 ||hot wire pipe || ||Blow a whistle at one end of a tube with a hot wire running down the axis to show areas of low and high luminosity. || ||3D30.66 ||Kundt's tube - impedance measurement || ||Use the oscilloscope to show variation of impedance in the driving coil with changes in tube length. || ||3D30.69 ||pressure distribution in a cavity || ||Liquid deformation on the bottom of an acoustic cavity shows the time-dependent pressure distribution in a standing sound wave. || ||3D30.70 ||hoot tubes ||pira200||A Bunsen burner heats a screen in the bottom of a large open vertical tube. || ||3D30.70 ||hoot tubes || ||Large glass tubes sound when a wire mesh at one end is heated with a Bunsen burner. || ||3D30.70 ||hoot tubes || ||A Bunsen burner heats a screen in the bottom of a large open tube. || ||3D30.70 ||hoot tubes || ||Singing tubes excited by hot gauze. || ||3D30.70 ||hoot tubes || ||Hints for making a singing tube work with only flame excitation. || ||3D30.70 ||singing pipes || ||Two metal tubes and a glass one. || ||3D30.71 ||hoot tube || ||Insert a fisher burner in a tube. || ||3D30.72 ||hoot tubes || ||The gauze in a hoot tube is held at the bottom of the tube and the flame is lit above it. || ||3D30.73 ||Rijke Tube - electrical heating || ||Construction of electrically heated Rijke tubes, tuning a T shaped tube. || ||3D30.74 ||variable hoot tubes || || || ||3D30.75 ||Knipp tubes || ||Knipp tubes are a special form of singing tube made by holding a short length of glass tube in the closed end of a larger tube. Picture. Ref. F.R.Watson, "Sound"p.214. || ||3D30.77 ||hot chocolate effect || ||Tap on a tall cylinder full of water and then repeat with hot water so there are lots of bubbles. The pitch descends three octaves and rises as the bubbles float up. || ||3D30.77 ||hot chocolate effect - comment || ||A few explanations from a physical chemist. || ||3D30.77 ||hot chocolate effect || ||Tap on the bottom of an empty glass, a full glass (higher pitch), and a glass full of tiny bubbles (pitch raises as glass clears. Methods of generating bubbles with beer and hot water. More. || <> = 3D32. Air Column Instruments = ||<10% style="text-align:center">'''PIRA #''' ||'''Demonstration Name''' ||'''Subsets'''||<60% style="text-align:center">'''Abstract''' || ||3D32.10 ||tin flute || ||Open and close holes on a tin flute to find pressure nodes and antinodes. || ||3D32.10 ||organ pipes with holes || ||Show open and closed pipes of various lengths and one with holes bored in the side to give the diatonic scale. || ||3D32.10 ||resonance tubes (three lengths) || ||Blow air out of a flat nozzle across a set of three different length tubes. || ||3D32.13 ||shrieker || ||Insert a 1/2" dia. tube 12" long into a bottle of water and blow across. || ||3D32.15 ||slide whistle || ||Use a high quality sliding whistle made for band. || ||3D32.15 ||variable pitch whistle || ||A whistle with a sliding piston. || ||3D32.15 ||slide whistle || ||The variable length organ pipe. || ||3D32.16 ||bird call || ||Directions for making a bird call. Diagram. || ||3D32.20 ||organ pipes with holes || || || ||3D32.24 ||[[Organ_Pipes]] || ||A collection of open, closed, and variable length organ pipes. || ||3D32.25 ||[[OpenClosedOrganPipes|Open and Closed End Organ Pipes]] || ||Three organ pipes, open and closed. || ||3D32.27 ||"C" bazooka || ||A 1.314 m brass tube sounds the note "C" when blown with the lips. || ||3D32.30 ||slide whistle || || || ||3D32.35 ||demonstration trumpet || ||Interchangeable mouthpiece, leadpipe, cylindrical section, and bell allow one to show the function of the various parts of the brass instruments. || ||3D32.36 ||hose in the bell || ||With a garden hose in the bell of a trombone (flush with the end), the tones are: 3:5:7:9:11 and without the hose: 2:3:4:5:6. || ||3D32.40 ||demonstration trumpet || || || ||3D32.40 ||PVC instruments, etc. || ||Very good instructions on making various instruments out of PVC. Also using a computer with a synthesizer to study scales. || = 3D40. Resonance in Plates, Bars, Solids = ||<10% style="text-align:center">'''PIRA #''' ||'''Demonstration Name''' ||'''Subsets'''||<60% style="text-align:center">'''Abstract''' || ||3D40.10 ||glockenspiel || ||A small xylophone can be played to demonstrate the musical scale. || ||3D40.10 ||xylophone || ||A small xylophone. || ||3D40.10 ||xylophone bars || ||Use a microphone and oscilloscope to display the waveforms of various notes on a xylophone. || ||3D40.11 ||rectangular bar oscillations || ||Strike a three foot rectangular bar on different faces and on the end. Listen to the different frequencies. || ||3D40.12 ||high frequency metal bars || ||Hold a metal rod at the midpoint and strike at the end. Two rods an octave apart are shown. || ||3D40.15 ||musical sticks || ||A set of wood sticks play a major scale when dropped on the lecture table. || ||3D40.15 ||musical sticks || ||A set of wood sticks is cut so they sound the musical scale when dropped. || ||3D40.15 ||musical sticks || ||Directions for making musical sticks. || ||3D40.15 ||musical sticks || ||A set of sticks give a complete scale when dropped. || ||3D40.16 ||musical nails || || || ||3D40.20 ||singing rod || ||Hold a long aluminum rod at the midpoint and stroke with rosened fingers. || ||3D40.20 ||singing rod ||pira200||A long aluminum rod will sing when held at the center and stroked with a rosin coated leather. || ||3D40.20 ||singing rods || ||Hold a long aluminum rod at the midpoint and stroke with rosined fingers. || ||3D40.21 ||singing rod || ||Stroke a 1/2" x 72" aluminum rod while holding at nodes to produce different harmonics. || ||3D40.23 ||bow the vertical rod || ||A long thin rod attached to a short thick rod clamped vertically is bowed and plucked while held at various positions. || ||3D40.24 ||regenerative feedback in rod || ||A detector at one end, speaker at the other, and an amplifier in between provides a regenerative feedback system for exciting a rod in the fundamental frequency. || ||3D40.24 ||speed of sound in a rod || ||Stroke a loud rod to get a squeal, tune a oscillator and speaker to get rid of beats, and calculate the velocity. || ||3D40.24 ||speed of sound in a metal wire || ||Wire is stretched tightly and stroked with a wet sponge. || ||3D40.24 ||velocity of sound in a rod || ||A rod clamped in the middle is excited by a coil at one end tuned until a Lissajous pattern is formed on an oscilloscope with the signal from a microphone placed at the other end. || ||3D40.24 ||singing rod || ||A rod is excited electromagnetically at one end and the motion is detected in the same manner at the other end for quantitative studies. || ||3D40.27 ||singing rod || ||Find Young's modulus by finding the sag in a rod and then compare the frequency of the fundamental mode with theory. || ||3D40.30 ||Chladni plate ||pira200||Strike or bow a horizontal metal plate covered with sand while touching the edge at various nodal points. Alternatively, the plate can be excited using a mechanincal vibrator and frequency generator. || ||3D40.30 ||Chladni plate || ||A brass plate clamped horizontally in the center is bowed while the edges are touched to provide user selected nodes. Banding sand shows patterns of oscillations. || ||3D40.30 ||Chladni plates || ||Bow the Chladni plate while damping at node locations with a finger. || ||3D40.30 ||Chladni plates || ||Excite the Chladni plates with a cello bow. Picture. || ||3D40.30 ||Chladni plate || ||A horizontal metal plate covered with sand is struck or bowed while touching the edge at various nodal points. || ||3D40.30 ||Chladni plates || ||Bow circular and square Chladni plates. || ||3D40.30 ||Chladni plates || ||A plate is driven by magnetostriction in the 10 to 30 Khz range. || ||3D40.31 ||Chladni plates || ||Sprinkled sand shows standing waves on a circular metal plate driven at the center by an oscillator. || ||3D40.31 ||Chladni plates || ||Drive a Chladni plate from the center. || ||3D40.32 ||[[ChladniPlateViolin|Chladni Plate: Violin]] || ||Directions for making a loudspeaker driven Chladni plate for the overhead projector. || ||3D40.32 ||Chladni plates || ||Chladni plates are driven from above by a loudspeaker. Pictures. || ||3D40.33 ||thick Chladni plate || ||A circular disc of 1/2" aluminum exhibits a single pattern. || ||3D40.34 ||Chladni plates || ||After some interesting historical and general comments, nonflat plates (cymbals, gongs, etc.) are examined. || ||3D40.35 ||2-D flame table || ||Two-dimensional rectangular and circular flame tables, extensions of the one-dimensional Rubens tube, are shown in some lower order modes || ||3D40.35 ||flaming birthday cake || ||Flames from a two dimensional array driven by a speaker show many resonant modes. || ||3D40.36 ||2D flame table analysis || ||An analysis of the two dimensional flame table. || ||3D40.40 ||Chladni figures - tympani head || ||Drive a timpani head with a loudspeaker. || ||3D40.40 ||standing waves on a drum || ||A speaker drives a circular rubber membrane under tension while illuminated with a strobe. || ||3D40.40 ||standing waves in a drum || ||A circular rubber membrane with a pattern is illuminated with a strobe and driven from below by a 12" loudspeaker. Pictures. || ||3D40.40 ||drumhead || ||A speaker drives a drumhead. || ||3D40.41 ||vibrations in a circular membrane || ||The eigenfrequencies of (21) agree closely with the theoretical values. Air damping is removed by using a wire mesh driven magnetically. || ||3D40.45 ||bubble membrane modes || ||Use a large right angle PVC fitting. || ||3D40.45 ||soap film membrane modes || ||Light from a slide projector is reflected off a soap film with a black cloth and speaker behind. || ||3D40.45 ||bubble membrane modes || ||A simple technique to drive bubble membranes of various shapes with a speaker. || ||3D40.50 ||musical goblets || ||Rub the edge of a goblet with a wet finger. || ||3D40.50 ||glass tumbler || ||Rub a finger dipped in vinegar around the top of a crystal goblet. || ||3D40.51 ||standing waves in a bowl || ||A 15 l flask is cut in half to form a bowl which is bowed to produce standing waves. Suspended ping pong balls indicate nodes and loops. || ||3D40.51 ||bowing the bowl || ||Suspend four pith balls so they touch the edge of a bowl and bow between two of the balls. || ||3D40.52 ||"whispering" waves in a wineglass || ||A thorough discussion of surface waves in vessels, including ethylene glycol in a trifle dish. || ||3D40.52 ||wineglass acoustics || ||A study of wineglass acoustics. || ||3D40.53 ||wine glass waves, etc. || ||Seven questions about wine glass waves are answered. Pictures of a glass harmonica and a Chinese "water spouting basin". || ||3D40.55 ||[[BreakingGlass|Breaking Glass with Sound]] ||pira200||A large 2" horn driver is used with an audio amplifier is used to break glassware/Stemware at it's resonant frequency by the use of an adjustable function generator to deliver a pure tone. Strobe light can be added to show the oscillations of the glass before it shatters. || ||3D40.60 ||wind chimes || ||Directions for making wind chimes. Some discussion of the perception of complex tones. || ||3D40.60 ||aeolian "bull roarer" || ||The Australian "bull-roarer" produces a loud noise due to eddies in the air. || ||3D40.65 ||bull roarer || || || ||3D40.90 ||spherical oscillations movie || ||A description by the author of a computer generated movie of spherical oscillations. || = 3D42. Percussion Instruments = ||<10% style="text-align:center">'''PIRA #''' ||'''Demonstration Name''' ||<60% style="text-align:center">'''Abstract''' || <> = 3D46. Tuning Forks = ||<10% style="text-align:center">'''PIRA #''' ||'''Demonstration Name''' ||'''Subsets'''||<60% style="text-align:center">'''Abstract''' || ||3D46.15 ||[[Tuning_Fork_Sets]] || ||Various sets of tuning forks are shown. || ||3D46.16 ||[[Tuning_Fork_Waveforms]] || ||Use a microphone and an oscilloscope to display the waveforms of tuning forks of varying frequencies. || ||3D46.20 ||Tuning Forks || ||Strike two tuning forks. Hold one against the table and the other in the air. When the first is no longer audible, hold the second on the table. || ||3D46.21 ||tuning forks || ||Compare losses of tuning forks of steel and alloy, on and off a resonator box. || ||3D46.22 ||adjustable tuning fork || ||Adjust masses on each tine of a large fork and show the waveform on an oscilloscope. Mistuned forks damp quickly. || ||3D46.25 ||modulation of sound waves || ||Two tuning forks of slightly different frequencies mounted on resonant boxes couple when the amplitude is varied by an oscillating barrier between them. || ||3D46.30 ||low frequency tuning fork || ||Tuning fork motion can be studied with a large fork. || ||3D46.31 ||project a tuning fork || ||Stroboscopically shadow project a vibrating tuning fork on a screen. || ||3D46.40 ||vowel tuning forks || ||A set of tuning forks made to give sounds that sound like the vowels. || ||3D46.45 ||quadrupole nature of a tuning fork || ||Hold a tuning fork close to the ear and rotate it. || ||3D46.90 ||frequency standard tuning forks || ||Driven precision tuning forks of 400 and 100 Hz are used as secondary frequency standards. || ||3D46.90 ||Electronically driven tuning fork || ||A tube circuit for driving a tuning fork. || ||3D46.90 ||electrically driven fork || ||A vacuum tube circuit for driving tuning forks. || = 3D50. Electronic Instruments = ||<10% style="text-align:center">'''PIRA #''' ||'''Demonstration Name''' ||<60% style="text-align:center">'''Abstract''' || ||3D50.10 ||keyboards || || [[Demonstrations]] [[Instructional|Home]]