PORTAL_Acoustics - Wikiparency

**Acoustics** is the science of mechanical waves in gases, liquids and solids — how they are made, how they travel, and how they are heard — and this portal is its front door on Wikitube: the vibration spine of the Centers of Excellence, article face [[Acoustics]]. It runs from the [[Oscillation|oscillation]] itself, through the [[Wave|wave]], [[Sound|sound]] and the [[Acoustic_wave_equation|wave equation]], into rooms, walls and water, the [[Hearing|ear]] and [[Musical_acoustics|music]], and out to the working world of every Minnesota State Center — engine knock, [[Ultrasound|ultrasound]], room treatment, grain-bin monitors, the hum of a transformer. Thirty sections, thirty microsims, thirty Main articles. Sibling spines: [[PORTAL_WT!Thury_Hydrodynamics_Compendium]] (fluids) and [[PORTAL_Signal_Processing]] (signals). Index: [[PORTAL_INDEX]] · systems root: [[PORTAL_Systems]]. ## How to read this page The page runs in five parts, from the thing that oscillates, through the wave that carries it, into rooms and materials, then the ear and music, and finally the trades that put sound to work. Each section is a short summary of a subject that has its own full article, named in the line under the heading; follow that link for the depth and the sources. Each section ends by naming the neighbors it connects to, so the page can be read straight through as one argument or entered anywhere. The plan behind the spine is `_registry/plans/PORTAL_ACOUSTICS_SECTIONS.md`. Every section also carries one microsim, and the thirty together are a set: `acoustics/` on the Wikitube three.js host, built from one portal pack and the `wt-acoustic.js` framework, so every one carries the same three lines — the equation it obeys, a readout of the numbers it is computing, and a caption that changes with the state you put it in. Drag to orbit, press *r* to reset, *space* to pause. Sound has no audio here; the picture carries the concept, and where a sim simplifies the physics it says so on screen with the word *illustrative*. Each See-also article under a hatnote inherits its section's sim as a variant, so a reader who follows a link into the depth finds the same instrument, retuned. The three older stations at the foot of the page (Movement I, Movement II, the Centers table and the player gallery) are kept as they were. **On the spine:** [[Acoustics]] · [[Sound]] · [[Wave]] · [[Oscillation]] · [[Vibration]] · sibling spines [[PORTAL_WT!Thury_Hydrodynamics_Compendium]] (fluids) and [[PORTAL_Signal_Processing]] (signals). ## Part I — The vibration: what oscillates Before there is a wave there is something that swings. Part I is the mechanics of that swing: a restoring force and an inertia, damping that eats it, a drive that feeds it, the resonance where feeding wins, and the strings and structures whose natural frequencies are the notes of the rest of the page. ### Oscillation  *Microsims from the articles this section links:* <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Simple_harmonic_motion.html" data-title="Simple harmonic motion"></div>  *Main article: [[Oscillation]] · See also: [[Simple_harmonic_motion]], [[Normal_mode]]* An oscillation is a motion that repeats about a resting point. A mass on a spring and a bob on a string look nothing alike, yet each is pulled back toward rest by a force that grows with the displacement, so each obeys the same equation and each traces the same closed curve in the phase plane of position against velocity. The period of the spring is set by mass and stiffness, the period of the pendulum by its length alone, and neither depends on how far it was pulled — the property that made the pendulum a clock. Energy trades back and forth between kinetic and potential and the total stays put. Everything later on this page is a variation on this one motion, coupled to a neighbor or spread along a medium.[^ups15] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Oscillation.html" data-title="Oscillation"></div> *Try: raise the spring constant and watch the spring's period fall while the pendulum's stays put; then lengthen the pendulum and watch the reverse. Widen the release angle and read how the pendulum's period grows past the small-angle value.* Connects to: [[#Damped and driven|Damped and driven]] · [[#Resonance|Resonance]] · [[#Strings|Strings]] · [[#Wave|Wave]] ### Damped and driven  *Microsims from the articles this section links:* <div class="wt-simrow"> <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/matter/Harmonic_oscillator.html" data-title="Harmonic oscillator · matter"></div> <div class="wt-sim" data-src="https://editor.p5js.org/sciencenibber/full/4YJFtvZAg" data-title="Harmonic oscillator · p5.js"></div> <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Damping.html" data-title="Damping · acoustics"></div> <div class="wt-sim" data-src="https://editor.p5js.org/sciencenibber/full/fZGuoWUHS" data-title="Damping · p5.js"></div> <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Q_factor.html" data-title="Q factor"></div> </div>  *Main article: [[Harmonic_oscillator]] · See also: [[Damping]], [[Q_factor]]* Real oscillators lose energy, and the rate at which they lose it is captured by one dimensionless number, the damping ratio. Below one the motion rings down inside a shrinking envelope; at one it returns to rest as fast as it can without overshooting; above one it creeps back. Shake the oscillator at a steady frequency and the story splits in two: a transient in which its own decaying ring-down beats against the forced motion, and a steady state in which it swings at the drive's frequency with an amplitude and a phase lag set by how close the drive sits to the natural frequency. The quality factor Q, the inverse of twice the damping ratio, says how many cycles the free ring-down lasts and how tall and narrow the steady-state peak will be.[^ups15] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Harmonic_oscillator.html" data-title="Harmonic oscillator"></div> *Try: set the drive to 0.85 of the natural frequency and watch the transient beats settle; then slide the damping ratio from 0.05 to 1 and read Q, the steady amplitude and the phase lag fall together.* Connects to: [[#Oscillation|Oscillation]] · [[#Resonance|Resonance]] · [[#Vibration|Vibration]] · [[#Acoustic resonance|Acoustic resonance]] ### Resonance *Main article: [[Resonance]] · See also: [[Sympathetic_resonance]], [[Tuning_fork]]* Push an oscillator at its own natural frequency and small pushes accumulate into a large swing: that is resonance, and one curve describes it for every linear system there is. The peak gain equals Q; the width of the peak at half power is the natural frequency divided by Q; and the phase of the response walks through a quarter cycle as the drive crosses the peak. A wine glass has a Q in the hundreds, so a tone held at its ring frequency can drive its rim through a strain the glass cannot survive — the party trick and the bridge failure are the same physics. The sections on rooms, strings, tubes and the ear are each a catalogue of what resonates and at what frequency.[^ups15] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Resonance.html" data-title="Resonance"></div> *Try: leave the sweep on and watch the drive walk through the peak; raise Q from 30 to 300 and watch the peak sharpen and the glass rim reach breaking strain at a lower drive level.* Connects to: [[#Damped and driven|Damped and driven]] · [[#Strings|Strings]] · [[#Acoustic resonance|Acoustic resonance]] · [[#Thermoacoustics|Thermoacoustics]] · [[#Oscillation|Oscillation]] ### Vibration  *Microsims from the articles this section links:* <div class="wt-simrow"> <div class="wt-sim" data-src="https://editor.p5js.org/sciencenibber/full/TFprpY6vu" data-title="Vibration"></div> <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/engineering/Vibration_isolation.html" data-title="Vibration isolation"></div> </div>  *Main article: [[Vibration]] · See also: [[Vortex-induced_vibration]], [[Vibration_isolation]]* A structure has as many natural frequencies as it has ways to move. Two masses on three springs are the smallest case: they can swing in step at one frequency or in opposition at a higher one, and any other motion is a mixture of the two that hands its energy back and forth between the masses. Real machines have thousands of such modes, and modal analysis is the trade of finding them before a passing truck or a spinning shaft does. The same theory answers the practical question of isolation: mount a machine on a spring soft enough that the disturbing frequency is more than about 1.4 times the mount's natural frequency and the mount transmits less than it receives, with damping helping at resonance and hurting above it.[^ups15] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Vibration.html" data-title="Vibration"></div> *Try: choose mode 1, then mode 2, then "both" and watch the energy trade between the masses; raise the coupling spring and read the two mode frequencies separate. Move the drive ratio past 1.4 and watch the transmissibility marker drop into the isolation band.* Connects to: [[#Damped and driven|Damped and driven]] · [[#Strings|Strings]] · [[#Soundproofing|Soundproofing]] · [[#Infrasound|Infrasound]] ### Strings *Main article: [[String_vibration]] · See also: [[Harmonic]], [[Fundamental_frequency]], [[Overtone]]* A string pinned at both ends can only hold standing waves that fit a whole number of half-wavelengths between the posts. Tension and mass per unit length fix the wave speed along the string; the length fixes which wavelengths fit; together they give a fundamental and a ladder of harmonics at exact multiples of it. A violin A-string 0.32 m long tuned to 440 Hz carries waves at about 282 m/s and needs a tension near 52 N to do it.[^gea] That whole-number ladder is why plucked and bowed strings sound musical, and why the next parts of this page can talk about harmonics, timbre and intervals with straight faces. <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/String_vibration.html" data-title="String vibration"></div> *Try: step the mode number from 1 to 8 and watch the nodes appear; raise the tension and the whole harmonic comb slides up the log-frequency axis; switch from the violin string to the bass string and it slides down.* Connects to: [[#Oscillation|Oscillation]] · [[#Resonance|Resonance]] · [[#Standing waves|Standing waves]] · [[#Musical acoustics|Musical acoustics]] · [[#Vibration|Vibration]] · [[#Beats|Beats]] ## Part II — The wave: how sound travels An oscillation coupled to its neighbors becomes a wave, and a wave in an elastic medium is sound. Part II is the physics of the travelling disturbance: the equation it obeys, the speed it moves at, how much of it there is, and what happens when two of them meet or the source moves. ### Wave  *Microsims from the articles this section links:* <div class="wt-simrow"> <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/matter/Wave.html" data-title="Wave"></div> <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Mechanical_wave.html" data-title="Mechanical wave"></div> </div>  *Main article: [[Wave]] · See also: [[Mechanical_wave]], [[Longitudinal_wave]]* A wave is a disturbance that travels while the medium stays home. The same function y(x, t) can drive a rope, whose beads move across the direction of travel, or a column of air, whose particles move along it; the first is transverse, the second longitudinal, and sound in a fluid is always the second. Two waves in the same medium simply add: pulses pass through one another and emerge unchanged, and where they overlap they reinforce or cancel. Frequency, wavelength and speed are tied by c = fλ, so a medium that carries sound faster stretches every wavelength in proportion.[^ups16] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Wave.html" data-title="Wave"></div> *Try: watch the tagged bead and the tagged column: each only oscillates in place while the pattern moves on. Switch the wave to "pulses, opposite" and watch two pulses cancel as they cross, then reappear.* Connects to: [[#Oscillation|Oscillation]] · [[#The acoustic wave equation|The acoustic wave equation]] · [[#Sound|Sound]] · [[#Standing waves|Standing waves]] ### The acoustic wave equation  *Microsims from the articles this section links:* <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Wave_equation.html" data-title="Wave equation"></div>  *Main article: [[Acoustic_wave_equation]] · See also: [[Wave_equation]], [[One-way_wave_equation]]* Conservation of mass and Newton's second law, written for small disturbances of a fluid, combine into one statement: the second time derivative of pressure equals the speed of sound squared times the Laplacian of pressure. Everything sound does in a room follows from that equation and the walls. Here it is solved in advance on a grid — a pressure puff released at rest in a two-dimensional box — and played back: the ring spreads at c, folds back off rigid walls, leaks out of an absorbing side, squeezes through a slit and fans out again as if the slit were a new source, or interferes with a second puff along a nodal line. The bake is the solver; the browser only interpolates.[^ups16] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Acoustic_wave_equation.html" data-title="Acoustic wave equation"></div> *Try: switch the room from closed box to open side to slit to two sources and watch the microphone trace on the right change with it; slow the playback to see the reflection fold.* Connects to: [[#Wave|Wave]] · [[#Sound|Sound]] · [[#Speed of sound|Speed of sound]] · [[#Acoustic resonance|Acoustic resonance]] ### Sound  *Microsims from the articles this section links:* <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Acoustic_wave.html" data-title="Acoustic wave"></div>  *Main article: [[Sound]] · See also: [[Acoustic_wave]], [[Particle_velocity]]* Sound in air is a longitudinal pressure wave: each parcel of air sways a few micrometres back and forth along the direction of travel, and where parcels crowd together the pressure is high, where they thin out it is low. Displacement and pressure are the same wave read two ways, a quarter of a cycle apart. At 20 °C the disturbance travels at 343 m/s in air, at about 1,480 m/s in water and near 6 km/s in steel, and because c = fλ the same 340 Hz tone that spans a metre in air spans seventeen in steel.[^ups17] The audible band, roughly 20 Hz to 20 kHz, is the ear's, not the wave's; Part V follows sound above and below it. <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Sound.html" data-title="Sound"></div> *Try: watch a single white tracer particle: it only sways about its home while the bands of compression march right. Switch the medium from air to helium to water to steel and read the wavelength stretch with the speed.* Connects to: [[#Wave|Wave]] · [[#The acoustic wave equation|The acoustic wave equation]] · [[#Speed of sound|Speed of sound]] · [[#Sound pressure and the decibel|Sound pressure and the decibel]] · [[#Transducers|Transducers]] ### Speed of sound *Main article: [[Speed_of_sound]] · See also: [[Sound_speed_gradient]], [[Refraction]]* Sound moves at the square root of a stiffness over a density. In an ideal gas that becomes √(γRT/M): the speed rises with temperature and falls with molecular mass, which is why helium carries sound almost three times faster than air and why a cold morning slows every sound by a few metres per second. Liquids and solids are stiffer by orders of magnitude, so water and steel outrun air even though they are far denser. Where the speed changes across a medium — warm air over cold ground, the ocean's thermocline — the wave bends toward the slower side, the refraction that carries a distant train's whistle at night and traps sound in the deep-ocean channel of Part V.[^ups17] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Speed_of_sound.html" data-title="Speed of sound"></div> *Try: restart the race and watch the steel front cross before the air front has gone a metre; drop the gas temperature to −40 °C and read the air speed fall; put helium in tube 1 and watch it nearly triple.* Connects to: [[#The acoustic wave equation|The acoustic wave equation]] · [[#Sound|Sound]] · [[#Doppler|Doppler]] · [[#Underwater acoustics|Underwater acoustics]] · [[#Infrasound|Infrasound]] · [[#Thermoacoustics|Thermoacoustics]] ### Sound pressure and the decibel  *Microsims from the articles this section links:* <div class="wt-simrow"> <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Decibel.html" data-title="Decibel · acoustics"></div> <div class="wt-sim" data-src="https://editor.p5js.org/sciencenibber/full/24mafFmdO" data-title="Decibel · p5.js"></div> </div>  *Main article: [[Sound_pressure]] · See also: [[Decibel]], [[Sound_intensity]]* The quietest sound a young ear can hear is a pressure swing of twenty millionths of a pascal; the loudest it can bear is a million times that. A ratio that wide is handled on a logarithmic scale, and the decibel of sound pressure level is twenty times the base-ten logarithm of the pressure over that threshold. Intensity, power per unit area, goes as pressure squared, so ten times the intensity is ten decibels and twice the pressure is six. A small source spreads its power over a growing sphere: intensity falls as the inverse square of distance, pressure as the inverse, and every doubling of distance costs six decibels. Two equal sources add three.[^ups17] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Sound_pressure.html" data-title="Sound pressure"></div> *Try: walk the listener from 1 m to 16 m and watch the meter drop 6 dB at each of the marked doublings; switch on the second source and read the meter add 3 dB while the field shows the interference between them.* Connects to: [[#Sound|Sound]] · [[#Attenuation|Attenuation]] · [[#Reverberation|Reverberation]] · [[#Hearing|Hearing]] · [[#Transducers|Transducers]] ### Standing waves *Main article: [[Standing_wave]] · See also: [[Kundt's_tube]], [[Wave_interference]]* A wave running one way and its reflection running the other add to a pattern that does not travel at all: nodes that never move and antinodes that swing twice as far. In a tube the ends decide which wavelengths fit — a tube open at both ends holds every harmonic of its fundamental, a tube closed at one end only the odd ones — and that rule is the whole theory of flutes, clarinets and organ pipes. Kundt found in 1866 that cork dust in such a tube gathers at the nodes, which turned the standing wave into a ruler for the speed of sound.[^ups17] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Standing_wave.html" data-title="Standing wave"></div> *Try: step the mode number and watch the cork dust settle at the new nodes; close one end and read the harmonic number jump to odd values only; lower the reflected amplitude below 1 and the nodes stop being silent.* Connects to: [[#Strings|Strings]] · [[#Wave|Wave]] · [[#Acoustic resonance|Acoustic resonance]] · [[#Thermoacoustics|Thermoacoustics]] ### Beats *Main article: [[Beat_(acoustics)]] · See also: [[Combination_tone]], [[Missing_fundamental]]* Two tones a few hertz apart slide in and out of step. Where they agree they add, half a beat later they cancel, and the loudness swells and fades at exactly the difference of the two frequencies. That swelling is how piano tuners hear a string drift and how an engine's two cylinders announce that they are slightly out of tune with each other. Past a difference of about fifteen hertz the ear stops counting beats and hears roughness instead, the sensation that Part IV turns into a theory of consonance.[^ups17] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Beat_(acoustics).html" data-title="Beat (acoustics)"></div> *Try: set the difference to 2 Hz and watch the long trace swell twice a second; push it past 15 Hz and watch the roughness readout climb as the beats blur.* Connects to: [[#Musical acoustics|Musical acoustics]] · [[#Noise|Noise]] · [[#Hearing|Hearing]] · [[#Strings|Strings]] ### Doppler  *Microsims from the articles this section links:* <div class="wt-simrow"> <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/matter/Doppler_effect.html" data-title="Doppler effect"></div> <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/Sonic_boom.html" data-title="Sonic boom"></div> <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Sonic_boom.html" data-title="Sonic boom · acoustics"></div> </div>  *Main article: [[Doppler_effect]] · See also: [[Sonic_boom]], [[Shock_wave]]* A source that moves crowds the wavefronts ahead of it and spreads the ones behind, so a listener ahead hears a higher pitch and one behind a lower; the observed frequency is f(c + v_o)/(c − v_s). Seen from the source itself the rings it has already emitted drift backward, bunching ahead and opening out behind. At Mach 1 the fronts ahead stack on top of one another; past it the source outruns its own sound and the fronts fold into a cone whose half-angle is the arcsine of 1/M — the shock a listener on the ground hears as a boom. The same shift, read from an echo, measures blood flow in Part V.[^ups17] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Doppler_effect.html" data-title="Doppler effect"></div> *Try: slide the Mach number from 0 to 0.9 and read the frequency ahead climb toward infinity while the one behind settles; push past 1 and watch the rings fold into the cone and the cone angle appear.* Connects to: [[#Speed of sound|Speed of sound]] · [[#Ultrasound|Ultrasound]] · [[#Underwater acoustics|Underwater acoustics]] · [[#Bioacoustics|Bioacoustics]] · [[#Sound localization|Sound localization]] ## Part III — Rooms and materials Once sound exists it meets things: walls, water, tissue, the air itself. Part III is the physics of the meeting — what resonates, what reflects, what is absorbed along the way, how long a room rings, how a wall stops it, and what to do about the noise that gets through. ### Acoustic resonance *Main article: [[Acoustic_resonance]] · See also: [[Helmholtz_resonance]], [[Resonator]]* A closed box of air only rings at the frequencies whose half-wavelengths fit between its walls: f = (c/2)√((l/Lx)² + (m/Ly)² + (n/Lz)²), one frequency for every triple of whole numbers. In a 5 m room the lowest sits near 34 Hz, and below a few hundred hertz the modes are sparse enough to hear one by one, which is why small rooms boom at particular bass notes. Above the Schroeder frequency they crowd into a statistical blur and the room can be treated by the reverberation theory of a later section. A bottle is the other kind of resonator, a slug of air in the neck bouncing on the spring of the air in the body.[^ups17] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Acoustic_resonance.html" data-title="Acoustic resonance"></div> *Try: step the mode numbers l and m and watch the pressure surface gain nodal lines; stretch the room length and read the mode frequency fall and the bars on the 0–200 Hz axis crowd together.* Connects to: [[#Damped and driven|Damped and driven]] · [[#Resonance|Resonance]] · [[#Standing waves|Standing waves]] · [[#Reverberation|Reverberation]] · [[#The acoustic wave equation|The acoustic wave equation]] · [[#The voice|The voice]] · [[#Thermoacoustics|Thermoacoustics]] ### Acoustic impedance *Main article: [[Acoustic_impedance]] · See also: [[Reflection_(physics)]], [[Acoustic_transmission_line]]* What a wave does at a boundary depends on one property of each medium, the characteristic impedance Z = ρc, density times sound speed. The fraction of intensity reflected is ((Z₂ − Z₁)/(Z₂ + Z₁))², and it does not care which medium is the denser: air against water sends 99.9 percent back, which is why an ultrasound probe needs gel and why a swimmer hears almost nothing of the pool deck. Tissue against bone reflects about half, tissue against tissue almost nothing, and that ladder of mismatches is the contrast in every ultrasound image. At an angle the transmitted beam bends by Snell's law, and past a critical angle it does not enter at all.[^ultra] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Acoustic_impedance.html" data-title="Acoustic impedance"></div> *Try: pair soft tissue with bone and read R near 50 percent; pair air with water and watch almost nothing get through; tilt the incidence angle past the critical angle and watch the transmitted wave vanish.* Connects to: [[#Attenuation|Attenuation]] · [[#Soundproofing|Soundproofing]] · [[#Ultrasound|Ultrasound]] · [[#Underwater acoustics|Underwater acoustics]] ### Attenuation *Main article: [[Acoustic_attenuation]] · See also: [[Stokes's_law_of_sound_attenuation]], [[Absorption_(acoustics)]]* Sound loses a fixed fraction of its energy per unit distance to viscosity, heat conduction and molecular relaxation, so its amplitude falls exponentially and its level falls on a straight line in decibels. The loss grows with frequency, roughly as a power law: in soft tissue about half a decibel per centimetre per megahertz, so a 10 MHz probe that resolves a tenth of a millimetre cannot see more than a few centimetres deep, while a 2 MHz probe sees the whole abdomen coarsely. In air the same law is why thunder rumbles from afar (the crack is gone) and why the previous Part's infrasound crosses continents.[^ultra] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Acoustic_attenuation.html" data-title="Acoustic attenuation"></div> *Try: raise the frequency from 2 to 15 MHz and watch the pulses die within the first centimetres while the maximum-depth readout collapses; switch the medium to bone and then to water.* Connects to: [[#Sound pressure and the decibel|Sound pressure and the decibel]] · [[#Acoustic impedance|Acoustic impedance]] · [[#Ultrasound|Ultrasound]] · [[#Underwater acoustics|Underwater acoustics]] ### Reverberation  *Microsims from the articles this section links:* <div class="wt-sim" data-src="https://editor.p5js.org/sciencenibber/full/MjYYSnoPW" data-title="Reverberation"></div>  *Main article: [[Reverberation]] · See also: [[Room_acoustics]], [[Architectural_acoustics]]* A clap in a room does not stop; it bounces, losing a fraction of its energy at every surface, and dies away at a steady number of decibels per second. Wallace Sabine, measuring Harvard's unusable Fogg lecture hall with an organ pipe and a stopwatch in the 1890s, found that the time for the sound to fall by sixty decibels is proportional to the room's volume and inversely to its total absorption: T₆₀ = 0.161 V/A. A concert hall wants about two seconds, a classroom about half a second, and every acoustic panel, curtain and audience member is a term in A.[^sabine] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Reverberation.html" data-title="Reverberation"></div> *Try: enlarge the room and watch T₆₀ grow; switch the walls from plaster to acoustic panel and watch the decay line steepen; seat an audience on the floor and read how much of the absorption they supply.* Connects to: [[#Sound pressure and the decibel|Sound pressure and the decibel]] · [[#Acoustic resonance|Acoustic resonance]] · [[#Soundproofing|Soundproofing]] · [[#Noise control|Noise control]] ### Soundproofing *Main article: [[Soundproofing]] · See also: [[Acoustic_panel]], [[Flanking_transmission]]* A wall stops sound by being heavy. The pressure wave has to shake the panel, and a massive panel barely moves, so the transmission loss of a single leaf climbs by about six decibels for every doubling of its surface mass or of the frequency — the mass law. It fails in two places: at the coincidence frequency, where the bending wave in the panel keeps step with the sound wave in air and the wall goes briefly transparent, and wherever sound finds a way around the wall through a duct, a ceiling or a shared floor, the flanking paths that decide most real rooms. Two light leaves with an air gap beat one heavy one above their mass–air–mass resonance.[^cremer] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Soundproofing.html" data-title="Soundproofing"></div> *Try: read the quiet-room level with a gypsum panel, then switch to brick; toggle the double leaf and widen the air gap; switch on the flanking path and watch the ceiling route cap the loss at 45 dB no matter the wall.* Connects to: [[#Vibration|Vibration]] · [[#Acoustic impedance|Acoustic impedance]] · [[#Reverberation|Reverberation]] · [[#Noise control|Noise control]] ### Noise control *Main article: [[Noise_control]] · See also: [[Active_noise_control]], [[Noise_pollution]]* Noise is fought at the source, along the path, or at the receiver. Along the path the workhorse is the barrier: a wall between source and listener forces the sound over its top edge, and the extra length of that detour, counted in half-wavelengths, is the Fresnel number that sets the depth of the acoustic shadow — Maekawa's curve gives about 13 dB at N = 1 and levels off near 24. High frequencies are stopped well and low ones barely, which is why a highway wall silences tyre hiss and not the bass of a diesel. At the receiver, active cancellation adds an inverted copy of the noise; it works only when the copy is right to within a few degrees of phase and a few percent of amplitude, which is why it lives inside headphones and not in concert halls.[^maekawa] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Noise_control.html" data-title="Noise control"></div> *Try: raise the barrier and watch the shadow deepen behind it; drop the frequency to 150 Hz and watch the shadow fill back in; then set the anti-noise phase error to 20° and read how little cancellation survives.* Connects to: [[#Reverberation|Reverberation]] · [[#Soundproofing|Soundproofing]] · [[#Noise|Noise]] · [[#Infrasound|Infrasound]] ## Part IV — Hearing and music Sound becomes hearing in a coiled tube smaller than a fingertip, and hearing becomes music by rules that the physics of Parts I and II set long before any culture chose them. Part IV is the ear, the two-eared brain, the harmonic series, the voice, and the sounds that are not tones at all. ### Hearing *Main article: [[Hearing]] · See also: [[Equal-loudness_contour]], [[Cochlea]]* In the cochlea a tone launches a travelling wave along the basilar membrane that grows, peaks and dies at one place: high frequencies near the base, low ones near the apex, on a logarithmic map that Greenwood fitted in 1990 and that packs ten octaves into 35 millimetres. How loud a tone seems depends on where it lands. The equal-loudness contours of ISO 226 show the ear most sensitive between 2 and 5 kHz, where the ear canal resonates, and needing sixty decibels more at 20 Hz to sound as loud as a quiet 1 kHz tone. Age steals the top of the map first.[^greenwood] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Hearing.html" data-title="Hearing"></div> *Try: sweep the tone from 100 Hz to 8 kHz and watch the peak of the travelling wave march from apex to base; hold the level at 40 dB and read the loudness in phon drop as you go below 200 Hz.* Connects to: [[#Sound pressure and the decibel|Sound pressure and the decibel]] · [[#Beats|Beats]] · [[#Sound localization|Sound localization]] · [[#Musical acoustics|Musical acoustics]] · [[#The voice|The voice]] · [[#Noise|Noise]] · [[#Transducers|Transducers]] ### Sound localization *Main article: [[Sound_localization]] · See also: [[Head-related_transfer_function]], [[3D_sound_localization]]* Two ears a head apart hear a source twice: the nearer ear first, and louder. The delay, up to about 0.65 milliseconds for a source straight to one side, follows Woodworth's geometry of a wave wrapping around a sphere; the level difference comes from the head's shadow and grows with frequency. Rayleigh's duplex theory of 1907 assigned the low frequencies to the delay and the high ones to the level, and the brain uses both, plus the pinna's own filtering, to place a sound in three dimensions from two signals.[^rayleigh] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Sound_localization.html" data-title="Sound localization"></div> *Try: swing the source from straight ahead to 90° and watch the interaural delay climb to its maximum; raise the frequency to 6 kHz and watch the level difference take over as the main cue.* Connects to: [[#Hearing|Hearing]] · [[#Underwater acoustics|Underwater acoustics]] · [[#Bioacoustics|Bioacoustics]] · [[#Doppler|Doppler]] ### Musical acoustics *Main article: [[Musical_acoustics]] · See also: [[Timbre]], [[Consonance_and_dissonance]]* A musical tone is a stack of harmonics at whole-number multiples of a fundamental, and its timbre is how strong each one is: a clarinet's odd harmonics against a sawtooth's full ladder. Sound two such tones together and some of their partials land close enough to beat; Plomp and Levelt showed in 1965 that the roughness of those near-misses, summed over all the pairs, dips exactly at the intervals every musical culture calls consonant — the octave, the fifth, the fourth, the thirds. Equal temperament spreads the twelve semitones evenly and lands within a few cents of those ratios, close enough to fool the ear on most of them.[^plomp] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Musical_acoustics.html" data-title="Musical acoustics"></div> *Try: slide the interval from 0 to 12 semitones and watch the roughness curve dip at the fifth and the major third and peak at the minor second; switch the timbre to clarinet and watch the dips move.* Connects to: [[#Strings|Strings]] · [[#Beats|Beats]] · [[#Hearing|Hearing]] · [[#The voice|The voice]] ### The voice *Main article: [[Formant]] · See also: [[Source–filter_model]], [[Ohm's_acoustic_law]]* The vocal folds buzz out a train of pulses whose spectrum is every harmonic of the pitch, falling steadily with frequency. The vocal tract above them is a tube about 17 cm long, closed at the glottis, with resonances near 500, 1500 and 2500 Hz that the tongue and lips move about; those resonances, the formants, lift some harmonics and sink others, and the pattern of the first two is the vowel. Peterson and Barney measured the pattern for American English in 1952 and it has been the map of vowel space ever since. Change the pitch and the vowel stays; change the tract and the vowel changes — source and filter are separate.[^peterson] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Formant.html" data-title="Formant"></div> *Try: switch the vowel from "heed" to "hod" to "who'd" and watch the marker cross the F1–F2 chart; raise the pitch and watch the harmonics thin out under the same formant envelope.* Connects to: [[#Musical acoustics|Musical acoustics]] · [[#Acoustic resonance|Acoustic resonance]] · [[#Hearing|Hearing]] · [[#Bioacoustics|Bioacoustics]] ### Noise *Main article: [[Noise]] · See also: [[Colors_of_noise]], [[Pink_noise]]* Noise is a random signal, described not by a waveform but by how its power spreads over frequency. White noise has the same power in every hertz; pink noise has the same power in every octave, which is why it sounds balanced to an ear that hears in octaves; brown noise piles its power into the bass and wanders like a drunk; blue and violet tilt the other way. The slopes are ±3 dB per octave for each step of the exponent, and a measured spectrum of a seeded sequence falls on its ideal line only when averaged, which is the first lesson of every spectrum analyser.[^thinkdsp] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Noise.html" data-title="Noise"></div> *Try: step the colour from white to pink to brown and watch the octave-band bars go from rising to flat to falling; change the seed and watch the waveform change while the spectrum does not.* Connects to: [[#Beats|Beats]] · [[#Noise control|Noise control]] · [[#Hearing|Hearing]] · [[#Infrasound|Infrasound]] ## Part V — Acoustics at work The eight Minnesota State Centers of Excellence each have an acoustic trade surface, and Part V is where the spine touches them: the probe in the HealthForce bay and the flaw detector on the Advanced Manufacturing floor, the sonar and the whale, the wind turbine and the transformer, the engine that sings, the bat, and the loudspeaker. ### Ultrasound  *Microsims from the articles this section links:* <div class="wt-simrow"> <div class="wt-sim" data-src="https://editor.p5js.org/sciencenibber/full/DhWu_2JUd" data-title="Ultrasound"></div> <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Medical_ultrasound.html" data-title="Medical ultrasound"></div> <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Ultrasonic_testing.html" data-title="Ultrasonic testing"></div> </div>  *Main article: [[Ultrasound]] · See also: [[Medical_ultrasound]], [[Ultrasonic_testing]]* Above 20 kHz sound is ultrasound, and at a few megahertz its wavelength in tissue is under a millimetre, short enough to image with. A probe sends a short pulse, every change of impedance along its path returns an echo, and the round-trip time gives the depth at 1,540 m/s. The trade is fixed by attenuation: higher frequency sharpens the picture and shortens the reach, so an abdominal probe works near 3 MHz and a superficial one near 12. The same pulse–echo through steel finds cracks and measures wall thickness, the nondestructive testing of the Advanced Manufacturing Center.[^ultra] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Ultrasound.html" data-title="Ultrasound"></div> *Try: raise the probe frequency and watch the axial resolution improve while the bone echo drops out of reach; thicken the fat layer; switch time-gain compensation on and watch the deep echoes come back up to the display.* Connects to: [[#Doppler|Doppler]] · [[#Acoustic impedance|Acoustic impedance]] · [[#Attenuation|Attenuation]] · [[#Bioacoustics|Bioacoustics]] · [[#Transducers|Transducers]] ### Underwater acoustics  *Microsims from the articles this section links:* <div class="wt-simrow"> <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/flight/Underwater_acoustics.html" data-title="Underwater acoustics"></div> <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Sonar.html" data-title="Sonar · acoustics"></div> <div class="wt-sim" data-src="https://editor.p5js.org/sciencenibber/full/JUw9ofgG6" data-title="Sonar · p5.js"></div> </div>  *Main article: [[Underwater_acoustics]] · See also: [[Sonar]], [[Animal_echolocation]]* In the ocean the speed of sound first falls with depth as the water cools and then rises again as the pressure grows, so there is a minimum near a kilometre down. Sound bends toward slower water, and a fan of rays from a source near that depth curls back toward the axis from above and below and cycles along it for thousands of kilometres with almost no loss: the SOFAR channel that Ewing and Worzel used to find downed airmen and that whales use to call across a basin. Munk's canonical profile of 1974 is the standard model of it, and every sonar range prediction starts by tracing rays through such a profile.[^munk] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Underwater_acoustics.html" data-title="Underwater acoustics"></div> *Try: put the source at 1,300 m and watch the whole fan stay trapped around the axis; raise it to 50 m under the summer profile and watch the rays dive and leave a shadow zone at the surface.* Connects to: [[#Speed of sound|Speed of sound]] · [[#Doppler|Doppler]] · [[#Acoustic impedance|Acoustic impedance]] · [[#Attenuation|Attenuation]] · [[#Sound localization|Sound localization]] ### Infrasound *Main article: [[Infrasound]] · See also: [[Aeolian_sound]], [[Mains_hum]]* Below 20 Hz we stop hearing sound as a tone, but it is still sound and its wavelength is enormous: at 2 Hz one cycle in air is 171 m long, longer than most buildings. Because air hardly absorbs it — thousandths of a decibel per kilometre against tens for the top of the audible band — infrasound from volcanoes, storms, wind turbines and nuclear tests crosses continents, and a global network of microbarometers listens for the last of these. At the other end of the same scale, the 120 Hz hum of a transformer core is the sound of magnetostriction at twice the line frequency, the Energy Center's own note.[^garces] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Infrasound.html" data-title="Infrasound"></div> *Try: set the frequency to 2 Hz and compare the wave with the turbine and the house; raise it to 100 Hz and watch the wave shrink to a few metres and the absorption over 10 km climb from nothing to noticeable.* Connects to: [[#Vibration|Vibration]] · [[#Speed of sound|Speed of sound]] · [[#Noise control|Noise control]] · [[#Noise|Noise]] ### Thermoacoustics *Main article: [[Thermoacoustics]] · See also: [[Rijke_tube]], [[Sound_amplification_by_stimulated_emission_of_radiation]]* Heat can drive sound and sound can pump heat. Rijke's tube of 1859, a vertical pipe open at both ends with a hot wire gauze inside, sings on its own when the gauze sits a quarter of the way up: Rayleigh's criterion says that heat added to the air while it is being compressed feeds the standing wave, and heat added while it expands drains it, so the same gauze moved to the upper half silences the tube. The modern descendants are thermoacoustic engines with no moving parts and refrigerators driven by a loudspeaker.[^rayleigh1878] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Thermoacoustics.html" data-title="Thermoacoustics"></div> *Try: leave the gauze at a quarter of the length and watch the note grow; slide it to three quarters and watch the growth rate turn negative and the tube die; switch the heater off and watch it coast down.* Connects to: [[#Resonance|Resonance]] · [[#Standing waves|Standing waves]] · [[#Acoustic resonance|Acoustic resonance]] · [[#Speed of sound|Speed of sound]] ### Bioacoustics *Main article: [[Bioacoustics]] · See also: [[Heart_sounds]], [[Otoacoustic_emission]]* Animals were the first sonar engineers. A bat sends out a sweep from about 80 down to 40 kHz and listens: the echo's delay gives the range at 2d/c, its pitch shift gives the target's speed, and the sweep's bandwidth sets how finely two echoes can be told apart. Griffin worked this out in the 1940s with a microphone that could hear what the bat heard. The same listening runs the other way in a clinic — heart sounds through a stethoscope, the faint otoacoustic emissions a healthy cochlea sends back out of the ear — and in a barn, where the Northern Agricultural Center reads herd health by ear and grain-bin level by echo.[^griffin] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Bioacoustics.html" data-title="Bioacoustics"></div> *Try: move the moth from 1 to 8 m and read the echo delay grow; give it a speed toward the bat and read the Doppler shift; shorten the call and watch the blind range shrink.* Connects to: [[#Doppler|Doppler]] · [[#Sound localization|Sound localization]] · [[#The voice|The voice]] · [[#Ultrasound|Ultrasound]] ### Transducers  *Microsims from the articles this section links:* <div class="wt-sim" data-src="https://editor.p5js.org/sciencenibber/full/MOYGtBLpj" data-title="Loudspeaker"></div>  *Main article: [[Loudspeaker]] · See also: [[Microphone]], [[Sound_level_meter]]* Every measurement and every reproduction of sound passes through a transducer, and the loudspeaker is the textbook case. A cone in a wall behaves as a piston of radius a: when the wavelength is much longer than the cone it radiates the same in every direction, and when the cone spans several wavelengths the sound squeezes into a beam whose width shrinks as 1/ka. A woofer is omnidirectional at 100 Hz and a searchlight at 5 kHz, which is why crossovers hand the treble to a smaller driver. Turn the piston around and the same pattern is a microphone's pickup, and a sound level meter is that microphone with the ear's weighting curve in front of the meter.[^kinsler] <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Loudspeaker.html" data-title="Loudspeaker"></div> *Try: at 150 Hz the pattern is a circle; raise the frequency to 5 kHz and watch the beam narrow and sidelobes appear; move the listener to 45° and read how many decibels off-axis they lose.* Connects to: [[#Sound|Sound]] · [[#Sound pressure and the decibel|Sound pressure and the decibel]] · [[#Hearing|Hearing]] · [[#Ultrasound|Ultrasound]] ## Notes [^ups15]: OpenStax, *University Physics Volume 1* (2016), Chapter 15, Oscillations (15.1–15.6): simple harmonic motion, energy, the pendulum, damped and forced oscillations. Portal Books shelf, book 077. [^ups16]: OpenStax, *University Physics Volume 1* (2016), Chapter 16, Waves (16.1–16.6): travelling waves, the wave equation, superposition, standing waves. Book 077. [^ups17]: OpenStax, *University Physics Volume 1* (2016), Chapter 17, Sound (17.1–17.8): sound waves, speed of sound (Table 17.1), intensity and the decibel, normal modes, beats, the Doppler effect, shock waves. Book 077. [^gea]: J. Gea-Banacloche, *University Physics I: Classical Mechanics* (2019), section 12.5.2, the violin string example (L = 0.32 m, 440 Hz, c = 282 m/s, T = 52.5 N). Book 076. [^ultra]: A. Thapaliya, A. Sithole, M. Welsh and G. Dana, *Ultrasound Physics and its Application in Medicine* (2024), sections 1.8 (reflection at an interface), 2.11 (attenuation) and 4.3 (pulse–echo imaging). Book 091. [^sabine]: W. C. Sabine, "Reverberation," *The American Architect and Building News* (1900), collected in *Collected Papers on Acoustics* (Harvard University Press, 1922). [^cremer]: L. Cremer, "Theorie der Schalldämmung dünner Wände bei schrägem Einfall," *Akustische Zeitschrift* 7 (1942), 81–104 — the coincidence effect; the mass law in its standard field-incidence form. [^maekawa]: Z. Maekawa, "Noise reduction by screens," *Applied Acoustics* 1 (1968), 157–173. https://doi.org/10.1016/0003-682X(68)90020-0 [^greenwood]: D. D. Greenwood, "A cochlear frequency-position function for several species — 29 years later," *Journal of the Acoustical Society of America* 87 (1990), 2592–2605. https://doi.org/10.1121/1.399052 ; ISO 226:2003, *Acoustics — Normal equal-loudness-level contours*. [^rayleigh]: Lord Rayleigh, "On our perception of sound direction," *Philosophical Magazine* 13 (1907), 214–232; R. S. Woodworth, *Experimental Psychology* (1938), the spherical-head interaural delay. [^plomp]: R. Plomp and W. J. M. Levelt, "Tonal consonance and critical bandwidth," *Journal of the Acoustical Society of America* 38 (1965), 548–560. https://doi.org/10.1121/1.1909741 ; the roughness curve drawn in the sim uses Sethares's parameterisation (1993) and is marked illustrative. [^peterson]: G. E. Peterson and H. L. Barney, "Control methods used in a study of the vowels," *Journal of the Acoustical Society of America* 24 (1952), 175–184. https://doi.org/10.1121/1.1906875 ; G. Fant, *Acoustic Theory of Speech Production* (1960). [^thinkdsp]: A. B. Downey, *Think DSP: Digital Signal Processing in Python* (2012), Chapter 4, Noise. Book 058. [^munk]: W. H. Munk, "Sound channel in an exponentially stratified ocean, with application to SOFAR," *Journal of the Acoustical Society of America* 55 (1974), 220–226. https://doi.org/10.1121/1.1914492 [^garces]: M. A. Garcés, "On infrasound standards, part 1: time, frequency, and energy scaling," *InfraMatics* 2 (2013), 13–35; ISO 9613-1:1993 for atmospheric absorption. [^rayleigh1878]: Lord Rayleigh, "The explanation of certain acoustical phenomena," *Nature* 18 (1878), 319–321; P. L. Rijke, "Notiz über eine neue Art, die in einer an beiden Enden offenen Röhre enthaltene Luft in Schwingungen zu versetzen," *Annalen der Physik* 183 (1859), 339–343. [^griffin]: D. R. Griffin, *Listening in the Dark: The Acoustic Orientation of Bats and Men* (Yale University Press, 1958). [^kinsler]: L. E. Kinsler, A. R. Frey, A. B. Coppens and J. V. Sanders, *Fundamentals of Acoustics* (4th ed., Wiley, 2000), the radiation of a circular piston (standard form); the sim sums 48 in-phase point sources and is marked illustrative in the near field. --- ## The original stations (kept) *Everything below this line is the portal as it stood before the 2026-09-12 rewrite — Movement I (three.js), Movement II (the p5.js editor stations), the Centers of Excellence crossings, the sign system and the generated player gallery. Nothing was removed.* ## Movement I — three.js microsims (first, per the spine rule)  *Microsims from the articles this section links:* <div class="wt-simrow"> <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/S_wave.html" data-title="S wave"></div> <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/Gravitational_wave.html" data-title="Gravitational wave"></div> <div class="wt-sim" data-src="https://editor.p5js.org/sciencenibber/full/pQPM1m6eN" data-title="Wave"></div> <div class="wt-sim" data-src="https://editor.p5js.org/sciencenibber/full/Q21EyK7NF" data-title="Oscillation"></div> </div>  | # | Station | Sim (three.js, netlify) | Explanatory spine | |---|---------|------------------------|-------------------| | 1 | [[Wave]] | `https://wikitube-3d-microsims.netlify.app/S_wave.html` | The S-wave sim shears a 3-D lattice sideways: the medium carries the disturbance while every particle comes home — the founding act of acoustics, rendered in depth. | | 2 | `Gravitational_wave` | `https://wikitube-3d-microsims.netlify.app/Gravitational_wave.html` | The limiting case that proves the spine: spacetime itself as the medium. Strain ellipses breathe in 3-D — listening at the largest possible scale. | | 3 | [[Oscillation]] | *build target — three.js pendulum-lattice* | The unit cell of sound: restoring force + inertia. Wave 2 build target on the [[Reveal|reveal]] lane. | | 4 | `Acoustic_resonance` | *build target — three.js modal room* | Standing waves in a box: the room modes every HealthForce ultrasound bay and Transportation cab share. | ## Movement II — p5.js microsims with explanatory text  *Microsims from the articles this section links:* <div class="wt-simrow"> <div class="wt-sim" data-src="https://editor.p5js.org/sciencenibber/full/90jeLsBsW" data-title="Acoustic wave"></div> <div class="wt-sim" data-src="https://editor.p5js.org/sciencenibber/full/Rnmcsvwbo" data-title="Mechanical wave"></div> <div class="wt-sim" data-src="https://editor.p5js.org/sciencenibber/full/YWAQ06VnR" data-title="Plane wave"></div> <div class="wt-sim" data-src="https://editor.p5js.org/sciencenibber/full/CN9h2kEA0" data-title="Sound"></div> </div>  The GENERATIVE Audio room already ships **21 live p5.js sims** (legacy `AUDIO_PORTAL`, 3 movements — the inline-embed model this portal inherits). Featured stations, fork links live: | # | Station | Sim (p5.js, /full embed) | Explanatory spine | |---|---------|--------------------------|-------------------| | 1 | `Acoustic_wave` | `https://editor.p5js.org/sciencenibber/full/90jeLsBsW` | Radial pressure wavefronts from a point source; scrub frequency and medium (air/water/steel), watch λ contract to keep c = f·λ, and hear the tone. | | 2 | `Mechanical_wave` | `https://editor.p5js.org/sciencenibber/full/Rnmcsvwbo` | Transverse and longitudinal side by side: one set of sliders drives the same y(x,t)=A·sin(kx−ωt) through both canonical mechanical-wave families at once. | | 3 | `Plane_wave` | `https://editor.p5js.org/sciencenibber/full/YWAQ06VnR` | The plane-wave idealization in two panels: a rasterized 2-D field p(x,y,t) and its 1-D slice, both driven by one propagating cosine. | | 4 | `Sound` | `https://editor.p5js.org/sciencenibber/full/CN9h2kEA0` | 220 air particles oscillate longitudinally, making bands of compression (red) and rarefaction (blue) visible above the analytic acoustic-pressure curve. | | 5 | [[Wave]] | `https://editor.p5js.org/sciencenibber/full/pQPM1m6eN` | The wave concept anatomized: a spatial snapshot brackets one wavelength and the amplitude, with a time view beneath — the same sinusoid, read two ways. | | + | — | *16 more in the Audio room gallery* | Migration of the full 21-sim gallery = Wave C of the run plan (`RUN_PLAN_acoustics_thury_coe`). | ## The Eight Centers of Excellence — acoustic crossings  *Microsims from the articles this section links:* <div class="wt-sim" data-src="https://editor.p5js.org/sciencenibber/full/rGvUcgG8H" data-title="Wave equation"></div>  Every Center of Excellence has an acoustic trade-surface; each row names its bridge article (blue = already local; `code` = wave-2 mint or WT! flagship build). | Center (WT! flagship — Wave A) | Host | Acoustic bridge | |---|---|---| | [[WT!Engineering_Center_of_Excellence]] | MSU Mankato | [[Wave_equation]] · `Vibration` — modal analysis, structural resonance | | [[WT!Advanced_Manufacturing_Center_of_Excellence]] | MSU Mankato | `Ultrasonic_testing` — NDT, chatter control on the spindle | | [[WT!Transportation_Center_of_Excellence]] | Dakota County TC | `Doppler_effect` · `Muffler` — exhaust tuning, cab NVH | | [[WT!Energy_Center_of_Excellence]] | Minnesota West CTC | [[Oscillation]] · `Transformer_hum` — grid acoustics, turbine monitoring | | [[WT!IT_Center_of_Excellence]] | Metropolitan State | `Digital_signal_processing` — codecs, rooms that talk to machines | | [[WT!HealthForce_Center_of_Excellence]] | Winona State | `Medical_ultrasound` · `Auscultation` — the stethoscope to the probe | | [[WT!Northern_Agricultural_Center_of_Excellence]] | Central Lakes (AgCentric) | `Bioacoustics` — herd health by ear, grain-bin level by echo | | [[WT!Southern_Agricultural_Center_of_Excellence]] | South Central College | `Noise_control` — barn ventilation, implement cab damping | **⊙ The Center Circle:** [[WT!Space_Mining_In_Minnesota]] — not a ninth Center but the hub the eight ring around (legacy precedent: the CoE portal's own "0 · FEATURED"). Seismology as acoustics: [[Wave]] mechanics through regolith; `S_wave` is its native sim. All roads on this spine lead back to it. ## Sign system This spine reads and writes `acoustic_diagrams` (11 rooms bridge it) — waveforms, spectrograms, staff-adjacent notation. Registry face: legacy `ICON_MASTER` (migrates in Wave C). --- *Spine portal, curated (WIKI_RULES §7, §14 all-blue applies to articles, not portal scaffolds — unbuilt links here are intentional forward-refs). Assets: netlify three.js roster + p5 sciencenibber gallery. Run plan: `_registry/plans/RUN_PLAN_acoustics_thury_coe.md`.* Third sibling spine: [[PORTAL_Signal_Processing]] (291 p5 sims, 9 movements).  ## Play every microsim on this page <p class="microsim-gallery-note">Every microsim linked from this portal, embedded live. <strong>40 players</strong> — 13 threejs · 27 p5js. 2 are staged but not yet deployed and show as placeholders.</p> <ul class="microsim-gallery"> <li class="microsim-card" data-lib="threejs"> <iframe src="https://wikitube-3d-microsims.netlify.app/polytope4d.html" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Four-dimensional polytopes — threejs microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!Three_js_Microsim_Master_Class">Four-dimensional polytopes</a></div><div class="ms-sub">threejs · <a href="https://wikitube-3d-microsims.netlify.app/polytope4d.html" target="_blank" rel="noopener">open full-screen</a> · on <a href="https://en.wikitube.io/wiki/WT!Three_js_Microsim_Master_Class">Three.js Microsim Master Class</a></div></div> </li> <li class="microsim-card" data-lib="threejs"> <iframe src="https://wikitube-3d-microsims.netlify.app/Klein_bottle.html" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Klein bottle — threejs microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!Three_js_Microsim_Master_Class">Klein bottle</a></div><div class="ms-sub">threejs · <a href="https://wikitube-3d-microsims.netlify.app/Klein_bottle.html" target="_blank" rel="noopener">open full-screen</a> · on <a href="https://en.wikitube.io/wiki/WT!Three_js_Microsim_Master_Class">Three.js Microsim Master Class</a></div></div> </li> <li class="microsim-card" data-lib="threejs"> <iframe src="https://wikitube-3d-microsims.netlify.app/Platonic_solid.html" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Platonic solids — threejs microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!Three_js_Microsim_Master_Class">Platonic solids</a></div><div class="ms-sub">threejs · <a href="https://wikitube-3d-microsims.netlify.app/Platonic_solid.html" target="_blank" rel="noopener">open full-screen</a> · on <a href="https://en.wikitube.io/wiki/WT!Three_js_Microsim_Master_Class">Three.js Microsim Master Class</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/90jeLsBsW" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Acoustics — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/Acoustics">Acoustics</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/90jeLsBsW" target="_blank" rel="noopener">open in the p5 editor</a> · on <a href="https://en.wikitube.io/wiki/WT!Engineering_Center_of_Excellence">Engineering Center of Excellence</a>, <a href="https://en.wikitube.io/wiki/WT!P5_js_Microsim_Master_Class">p5.js Microsim Master Class</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/CN9h2kEA0" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Acoustics — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/Acoustics">Acoustics</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/CN9h2kEA0" target="_blank" rel="noopener">open in the p5 editor</a> · on <a href="https://en.wikitube.io/wiki/WT!Energy_Center_of_Excellence">Energy Center of Excellence</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/Rnmcsvwbo" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Acoustics — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/Acoustics">Acoustics</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/Rnmcsvwbo" target="_blank" rel="noopener">open in the p5 editor</a> · on <a href="https://en.wikitube.io/wiki/WT!Advanced_Manufacturing_Center_of_Excellence">Advanced Manufacturing Center of Excellence</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/YWAQ06VnR" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Acoustics — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/Acoustics">Acoustics</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/YWAQ06VnR" target="_blank" rel="noopener">open in the p5 editor</a> · on <a href="https://en.wikitube.io/wiki/WT!Transportation_Center_of_Excellence">Transportation Center of Excellence</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/mdgpEb9UH" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Acoustics — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/Acoustics">Acoustics</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/mdgpEb9UH" target="_blank" rel="noopener">open in the p5 editor</a> · on <a href="https://en.wikitube.io/wiki/WT!Northern_Agricultural_Center_of_Excellence">Northern Agricultural Center of Excellence</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/pQPM1m6eN" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Acoustics — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/Acoustics">Acoustics</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/pQPM1m6eN" target="_blank" rel="noopener">open in the p5 editor</a> · on <a href="https://en.wikitube.io/wiki/Wave">Wave</a>, <a href="https://en.wikitube.io/wiki/WT!IT_Center_of_Excellence">IT Center of Excellence</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/YQ1jdugGs" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Advanced Manufacturing Center of Excellence — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!Advanced_Manufacturing_Center_of_Excellence">Advanced Manufacturing Center of Excellence</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/YQ1jdugGs" target="_blank" rel="noopener">open in the p5 editor</a> · on <a href="https://en.wikitube.io/wiki/WT!HealthForce_Center_of_Excellence">HealthForce Center of Excellence</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/tqkls7TH0" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Advanced Manufacturing Center of Excellence — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!Advanced_Manufacturing_Center_of_Excellence">Advanced Manufacturing Center of Excellence</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/tqkls7TH0" target="_blank" rel="noopener">open in the p5 editor</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/tHGSVAofH" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Aliasing — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!P5_js_Microsim_Master_Class">Aliasing</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/tHGSVAofH" target="_blank" rel="noopener">open in the p5 editor</a> · on <a href="https://en.wikitube.io/wiki/WT!P5_js_Microsim_Master_Class">p5.js Microsim Master Class</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/FrVY75N0P" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Energy Center of Excellence — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!Energy_Center_of_Excellence">Energy Center of Excellence</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/FrVY75N0P" target="_blank" rel="noopener">open in the p5 editor</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/XyMhYXxqj" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Energy Center of Excellence — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!Energy_Center_of_Excellence">Energy Center of Excellence</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/XyMhYXxqj" target="_blank" rel="noopener">open in the p5 editor</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/LrZ3_kDcz" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Engineering Center of Excellence — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!Engineering_Center_of_Excellence">Engineering Center of Excellence</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/LrZ3_kDcz" target="_blank" rel="noopener">open in the p5 editor</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/suggb6pQy" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Engineering Center of Excellence — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!Engineering_Center_of_Excellence">Engineering Center of Excellence</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/suggb6pQy" target="_blank" rel="noopener">open in the p5 editor</a> · on <a href="https://en.wikitube.io/wiki/WT!Transportation_Center_of_Excellence">Transportation Center of Excellence</a>, <a href="https://en.wikitube.io/wiki/WT!Space_Mining_In_Minnesota">Space Mining In Minnesota</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/EKxWMazJF" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="HealthForce Center of Excellence — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!HealthForce_Center_of_Excellence">HealthForce Center of Excellence</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/EKxWMazJF" target="_blank" rel="noopener">open in the p5 editor</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/lmVzpqGH4" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="HealthForce Center of Excellence — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!HealthForce_Center_of_Excellence">HealthForce Center of Excellence</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/lmVzpqGH4" target="_blank" rel="noopener">open in the p5 editor</a> · on <a href="https://en.wikitube.io/wiki/WT!Northern_Agricultural_Center_of_Excellence">Northern Agricultural Center of Excellence</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/HVNGd9nMv" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Histogram — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!P5_js_Microsim_Master_Class">Histogram</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/HVNGd9nMv" target="_blank" rel="noopener">open in the p5 editor</a> · on <a href="https://en.wikitube.io/wiki/WT!P5_js_Microsim_Master_Class">p5.js Microsim Master Class</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/87KvqaOYZ" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="IT Center of Excellence — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!IT_Center_of_Excellence">IT Center of Excellence</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/87KvqaOYZ" target="_blank" rel="noopener">open in the p5 editor</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/jDSVr9k4y" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="IT Center of Excellence — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!IT_Center_of_Excellence">IT Center of Excellence</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/jDSVr9k4y" target="_blank" rel="noopener">open in the p5 editor</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/7S176uP2p" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Northern Agricultural Center of Excellence — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!Northern_Agricultural_Center_of_Excellence">Northern Agricultural Center of Excellence</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/7S176uP2p" target="_blank" rel="noopener">open in the p5 editor</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/Q21EyK7NF" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Oscillation — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/Oscillation">Oscillation</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/Q21EyK7NF" target="_blank" rel="noopener">open in the p5 editor</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/gECvsn3vl" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Southern Agricultural Center of Excellence — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!Southern_Agricultural_Center_of_Excellence">Southern Agricultural Center of Excellence</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/gECvsn3vl" target="_blank" rel="noopener">open in the p5 editor</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/o-xhfXiSJ" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Southern Agricultural Center of Excellence — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!Southern_Agricultural_Center_of_Excellence">Southern Agricultural Center of Excellence</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/o-xhfXiSJ" target="_blank" rel="noopener">open in the p5 editor</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/pC6Yt_OQu" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Southern Agricultural Center of Excellence — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!Southern_Agricultural_Center_of_Excellence">Southern Agricultural Center of Excellence</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/pC6Yt_OQu" target="_blank" rel="noopener">open in the p5 editor</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/7nmV7CQZc" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Space Mining In Minnesota — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!Space_Mining_In_Minnesota">Space Mining In Minnesota</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/7nmV7CQZc" target="_blank" rel="noopener">open in the p5 editor</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/jQW91Jdyf" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Space Mining In Minnesota — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!Space_Mining_In_Minnesota">Space Mining In Minnesota</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/jQW91Jdyf" target="_blank" rel="noopener">open in the p5 editor</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/8AMqqIG1_" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Transportation Center of Excellence — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!Transportation_Center_of_Excellence">Transportation Center of Excellence</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/8AMqqIG1_" target="_blank" rel="noopener">open in the p5 editor</a></div></div> </li> <li class="microsim-card" data-lib="p5js"> <iframe src="https://editor.p5js.org/sciencenibber/full/rGvUcgG8H" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Wave equation (p5.js) — p5js microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/Wave_equation">Wave equation (p5.js)</a></div><div class="ms-sub">p5js · <a href="https://editor.p5js.org/sciencenibber/full/rGvUcgG8H" target="_blank" rel="noopener">open in the p5 editor</a> · on <a href="https://en.wikitube.io/wiki/Wave_equation">Wave equation</a></div></div> </li> <li class="microsim-card" data-lib="threejs"> <iframe src="https://wikitube-3d-microsims.netlify.app/Deep_inelastic_scattering.html" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Deep inelastic scattering — threejs microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!IT_Center_of_Excellence">Deep inelastic scattering</a></div><div class="ms-sub">threejs · <a href="https://wikitube-3d-microsims.netlify.app/Deep_inelastic_scattering.html" target="_blank" rel="noopener">open full-screen</a> · on <a href="https://en.wikitube.io/wiki/WT!IT_Center_of_Excellence">IT Center of Excellence</a></div></div> </li> <li class="microsim-card is-pending" data-lib="threejs"> <div class="ms-placeholder">Staged, not yet deployed — <code>Eddy_(fluid_dynamics).html</code></div> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!Transportation_Center_of_Excellence">Eddy (fluid dynamics)</a></div><div class="ms-sub">threejs · awaiting CDN deploy · on <a href="https://en.wikitube.io/wiki/WT!Transportation_Center_of_Excellence">Transportation Center of Excellence</a>, <a href="https://en.wikitube.io/wiki/WT!Southern_Agricultural_Center_of_Excellence">Southern Agricultural Center of Excellence</a></div></div> </li> <li class="microsim-card" data-lib="threejs"> <iframe src="https://wikitube-3d-microsims.netlify.app/Energy_conservation.html" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Energy conservation — threejs microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!Energy_Center_of_Excellence">Energy conservation</a></div><div class="ms-sub">threejs · <a href="https://wikitube-3d-microsims.netlify.app/Energy_conservation.html" target="_blank" rel="noopener">open full-screen</a> · on <a href="https://en.wikitube.io/wiki/WT!Energy_Center_of_Excellence">Energy Center of Excellence</a></div></div> </li> <li class="microsim-card" data-lib="threejs"> <iframe src="https://wikitube-3d-microsims.netlify.app/Geophysical_fluid_dynamics.html" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Geophysical fluid dynamics — threejs microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!IT_Center_of_Excellence">Geophysical fluid dynamics</a></div><div class="ms-sub">threejs · <a href="https://wikitube-3d-microsims.netlify.app/Geophysical_fluid_dynamics.html" target="_blank" rel="noopener">open full-screen</a> · on <a href="https://en.wikitube.io/wiki/WT!IT_Center_of_Excellence">IT Center of Excellence</a>, <a href="https://en.wikitube.io/wiki/WT!Northern_Agricultural_Center_of_Excellence">Northern Agricultural Center of Excellence</a>, <a href="https://en.wikitube.io/wiki/WT!Space_Mining_In_Minnesota">Space Mining In Minnesota</a></div></div> </li> <li class="microsim-card" data-lib="threejs"> <iframe src="https://wikitube-3d-microsims.netlify.app/Gravitational_wave.html" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Gravitational wave — threejs microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/Acoustics">Gravitational wave</a></div><div class="ms-sub">threejs · <a href="https://wikitube-3d-microsims.netlify.app/Gravitational_wave.html" target="_blank" rel="noopener">open full-screen</a> · on <a href="https://en.wikitube.io/wiki/Acoustics">Acoustics</a>, <a href="https://en.wikitube.io/wiki/WT!Transportation_Center_of_Excellence">Transportation Center of Excellence</a>, <a href="https://en.wikitube.io/wiki/WT!Southern_Agricultural_Center_of_Excellence">Southern Agricultural Center of Excellence</a></div></div> </li> <li class="microsim-card" data-lib="threejs"> <iframe src="https://wikitube-3d-microsims.netlify.app/Hydrodynamics.html" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Hydrodynamics — threejs microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!Engineering_Center_of_Excellence">Hydrodynamics</a></div><div class="ms-sub">threejs · <a href="https://wikitube-3d-microsims.netlify.app/Hydrodynamics.html" target="_blank" rel="noopener">open full-screen</a> · on <a href="https://en.wikitube.io/wiki/WT!Engineering_Center_of_Excellence">Engineering Center of Excellence</a>, <a href="https://en.wikitube.io/wiki/WT!Energy_Center_of_Excellence">Energy Center of Excellence</a>, <a href="https://en.wikitube.io/wiki/WT!HealthForce_Center_of_Excellence">HealthForce Center of Excellence</a></div></div> </li> <li class="microsim-card is-pending" data-lib="threejs"> <div class="ms-placeholder">Staged, not yet deployed — <code>Moiré_pattern.html</code></div> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!Advanced_Manufacturing_Center_of_Excellence">Moiré pattern</a></div><div class="ms-sub">threejs · awaiting CDN deploy · on <a href="https://en.wikitube.io/wiki/WT!Advanced_Manufacturing_Center_of_Excellence">Advanced Manufacturing Center of Excellence</a></div></div> </li> <li class="microsim-card" data-lib="threejs"> <iframe src="https://wikitube-3d-microsims.netlify.app/Porous_medium.html" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Porous medium — threejs microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!Advanced_Manufacturing_Center_of_Excellence">Porous medium</a></div><div class="ms-sub">threejs · <a href="https://wikitube-3d-microsims.netlify.app/Porous_medium.html" target="_blank" rel="noopener">open full-screen</a> · on <a href="https://en.wikitube.io/wiki/WT!Advanced_Manufacturing_Center_of_Excellence">Advanced Manufacturing Center of Excellence</a>, <a href="https://en.wikitube.io/wiki/WT!Space_Mining_In_Minnesota">Space Mining In Minnesota</a></div></div> </li> <li class="microsim-card" data-lib="threejs"> <iframe src="https://wikitube-3d-microsims.netlify.app/S_wave.html" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="S wave — threejs microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/Acoustics">S wave</a></div><div class="ms-sub">threejs · <a href="https://wikitube-3d-microsims.netlify.app/S_wave.html" target="_blank" rel="noopener">open full-screen</a> · on <a href="https://en.wikitube.io/wiki/Acoustics">Acoustics</a>, <a href="https://en.wikitube.io/wiki/WT!Engineering_Center_of_Excellence">Engineering Center of Excellence</a>, <a href="https://en.wikitube.io/wiki/WT!HealthForce_Center_of_Excellence">HealthForce Center of Excellence</a>, <a href="https://en.wikitube.io/wiki/WT!Northern_Agricultural_Center_of_Excellence">Northern Agricultural Center of Excellence</a>, <a href="https://en.wikitube.io/wiki/WT!Space_Mining_In_Minnesota">Space Mining In Minnesota</a></div></div> </li> <li class="microsim-card" data-lib="threejs"> <iframe src="https://wikitube-3d-microsims.netlify.app/Vapour_pressure_of_water.html" loading="lazy" frameborder="0" sandbox="allow-scripts allow-same-origin" title="Vapour pressure of water — threejs microsim"></iframe> <div class="ms-meta"><div class="ms-title"><a href="https://en.wikitube.io/wiki/WT!Energy_Center_of_Excellence">Vapour pressure of water</a></div><div class="ms-sub">threejs · <a href="https://wikitube-3d-microsims.netlify.app/Vapour_pressure_of_water.html" target="_blank" rel="noopener">open full-screen</a> · on <a href="https://en.wikitube.io/wiki/WT!Energy_Center_of_Excellence">Energy Center of Excellence</a></div></div> </li> </ul>   **Craft standard:** Both craft standards apply here — [[WT!Three_js_Microsim_Master_Class|three.js]] and [[WT!P5_js_Microsim_Master_Class|p5.js]].  --- *Repopulated 2026-09-19 · append-only · source: _tools/generate/g34_portal_section_sims.py@00a28cb2 (players of the linked articles, each URL 200-checked) · 137 added · 0 deletions*