327 plain definitions for the vocabulary the rest of the site assumes: waves, apparatus, rigs, optics, sound, and the claims that swirl around all of it. Written to be read cold, and to say what a word means rather than what it is marketed as.
A lookup table that maps input RGB values to output RGB values on a three-dimensional lattice, interpolating between the points. Cubes of 33 by 33 by 33 stored as .cube files are common. It is how log footage is converted to a display look, whether as an on-set preview or the basis of a grade.
Research from Li-Huei Tsai's lab at MIT in which mice, and later small groups of people, receive light flicker, clicks or whole-body vibration at 40 Hz. Mouse studies from 2016 onwards reported less Alzheimer's pathology; two small human trials (43 and 15 participants) found it safe with encouraging signs, which Tsai herself called 'not sufficient evidence of efficacy'. It is sensory stimulation, not cymatics.
A tuning with A set to 432 Hz instead of 440 Hz, about 32 cents flat. Advocates say it is ancient, natural, aligned with the Schumann resonance and yields prettier cymatic figures. None of this holds up: ancient cultures could not measure frequency, Verdi backed 435 Hz, the Schumann link relies on rounding, and any plate shows figures at whatever frequency it resonates. The few small studies are mixed.
See A440 concert pitch, Schumann resonance, Solfeggio frequencies
4K UHD is 3840 by 2160 pixels, exactly double 1080p in each direction, with a cinema variant of 4096 by 2160. 8K UHD is 7680 by 4320, about 33 million pixels. Higher resolution helps fine ripple and grain detail but multiplies storage, encoding time and delivery bandwidth.
See Aspect ratio, Bit rate
Consumer 4K, or UHD, is 3840 by 2160 pixels, about 8.3 million, exactly four times the pixel count of 1080p; cinema DCI 4K is 4096 by 2160. 8K UHD doubles both dimensions again to 7680 by 4320. Higher resolution reveals fine ripple structure but needs more light, storage and bandwidth.
See Aspect ratio, Bit rate, Video codec
The best-known Solfeggio frequency, marketed as the 'love' or 'DNA repair' tone. It is roughly a sharp C in 440 Hz tuning. The DNA claim rests on no accepted biology; the handful of published experiments are mostly in vitro and tentative. Listening to a 528 Hz tone is harmless but there is no evidence it does what is claimed.
A filter applied to sound-level readings so that they roughly follow the ear's sensitivity, which falls off at low and very high frequencies. Occupational noise limits are written in dBA. Because it discounts bass, an A-weighted meter can under-report the low-frequency energy that a subwoofer-driven cymatics rig actually puts out.
See Decibel, Hearing safety, Loudness
The standard that fixes the A above middle C at 440 Hz, agreed at a London conference in 1939 and later published as ISO 16. It is not universal: continental European orchestras commonly play between 440 and 444 Hz, and period ensembles often use a baroque pitch of 415 Hz.
See 432 Hz, Equal temperament, Pitch
The convention that the A above middle C is 440 Hz. It emerged in the American music trade in the 1920s and 1930s, was recommended by ISO in 1955 and formalised as ISO 16 in 1975. Earlier standards included the French 435 Hz of the 1860s. It is a shared reference for playing together, not a claim about nature.
See 432 Hz, Equal temperament, Hertz
A measure of how much a medium resists being set into sound motion; for a plane wave it is the medium's density times its speed of sound. Where impedance changes sharply, as between air and water, most sound energy reflects rather than passing through, which is why driving a liquid from a loudspeaker through the air is inefficient.
Holding small objects in mid-air at the pressure nodes of an intense ultrasonic standing wave. Arrays of 40 kHz transducers, such as the University of Bristol's TinyLev design from 2017, can be built from off-the-shelf parts and have levitated droplets, polystyrene beads and insects. It is a genuine demonstration of sound moving matter, unlike most 'frequency' claims.
The small steady push that a sound wave exerts on a surface or an object in its path, over and above the oscillating sound pressure. It is what allows acoustic levitation of small beads at the nodes of a standing wave, and it contributes to particles and droplets drifting to particular positions in strong sound fields.
A steady flow set up in a fluid by strong sound or vibration, as distinct from the back-and-forth motion of the wave itself; it arises from the wave's energy being absorbed near boundaries or in the bulk. It drives fine powders to the antinodes of a Chladni plate and produces slow circulation in liquid cymatics vessels.
The model for mixing light rather than pigment. Red, green and blue combine at full intensity to make white, and pairs give yellow, cyan and magenta. It is the model behind every RGB LED ring and every display: what you set in code is a mix of three emitters, not a paint colour.
German researcher and photographer, born in Überlingen in 1951, who has worked on cymatics since 1993 building on Chladni and Jenny. He photographs water surfaces driven by sine tones, music and overtone chanting, published Wasser Klang Bilder in 2002 and Water Sound Images in English, and gives lectures and live water-sound concerts.
A false low-frequency pattern created when something is sampled too slowly, which happens whenever the sampled frequency exceeds half the sampling rate. In video, temporal aliasing gives wagon-wheel and frozen-ripple effects; in images, spatial aliasing shows as moire. Cymatics footage is prone to it because the plate vibrates faster than any ordinary frame rate.
The size of a vibration: how far a point moves from its rest position, or how much a pressure or voltage swings. It can be quoted as peak, peak-to-peak or RMS values. In cymatics amplitude decides whether sand merely jiggles, walks to the nodes or bounces off the plate, and whether a liquid stays flat or breaks into Faraday waves.
See Frequency, Faraday wave
A place in a standing wave where the medium moves the furthest, midway between nodes. On a Chladni plate the antinodes are the areas that shed sand; very fine powders can behave the opposite way and gather at the antinodes, carried there by air currents that the vibrating plate sets up.
An Italian open-source hardware and software company, and by extension its family of single-board microcontrollers and the environment used to program them in C and C++. Boards run from 8-bit AVR parts to 32-bit ARM ones and expose digital and analogue pins, which makes them the usual starting point for a homemade LED or strobe controller.
A royalty-free protocol from Artistic Licence, introduced in 1998, that carries DMX512 and RDM over ordinary Ethernet using UDP on port 6454. Later versions address up to 32,768 universes. It lets one network cable replace many DMX runs, which matters as soon as a rig has more LED channels than a single universe holds.
A pleasant tingling that starts on the scalp and spreads down the neck in some people, triggered by whispering, tapping, scratching and close personal attention in videos. The name was proposed by Jennifer Allen in 2010. Brain-imaging work suggests it is real for those who feel it, roughly half of people; research remains limited and it makes no cymatic or healing claims.
The ratio of an image's width to its height. 16:9 is standard for television and most web video, 9:16 is vertical phone video, 1:1 is square and 2.39:1 is widescreen cinema. Circular plates and dishes sit awkwardly in wide frames, so many cymatics clips are cropped square or vertical for social platforms.
Any vibration in the audible band of roughly 20 Hz to 20 kHz. Below about 32 Hz lie the lowest organ pedal notes, 32 to 512 Hz carries rhythm and bass, 512 Hz to 2 kHz speech intelligibility, and above 8 kHz the brilliance of bells and cymbals. Most water and plate cymatics lives in the bottom two octaves of this band.
See Hearing range, Hertz, Infrasound
Computer hardware that moves audio in and out of a machine with low-latency conversion and proper line and microphone connections, rather than the basic playback a built-in sound chip offers. For a cymatics rig it is the usual way to send a clean, level-controlled drive signal to the power amplifier and to record what a microphone hears.
One sound making another harder or impossible to hear. It is strongest when the two are close in frequency (within the ear's critical band) and also works briefly in time before and after a loud event. Lossy audio codecs exploit it; sound-bath and sleep-noise products rely on it to cover tinnitus or room noise.
An open, royalty-free video codec from the Alliance for Open Media, whose specification was released in 2018. Testing cited by Wikipedia showed bitrates around half those of x264 for similar quality. Chrome and Firefox play it, which makes it attractive for lightweight web loops, though encoding is slow and some older devices cannot decode it.
Lighting the subject from behind, so the source and the camera face each other. It separates the subject from its background, makes translucent things glow and turns thin edges into bright rims. A soap film or shallow water dish lit from behind shows interference colours and wave structure that front light washes out.
Lighting the subject from behind, with the camera facing towards the light. It rims edges, separates subject from background and, at high ratios, produces a silhouette. Shooting a water dish or a bubble against a diffused panel is the standard way to turn surface shape into brightness.
The slow pulsing in volume heard when two tones of slightly different frequency sound together; the pulse rate equals the difference between them. Piano and organ tuners count beats to set intervals, and on a rig the effect makes a near-miss frequency audible before you can see it.
See Binaural beats, Consonance and dissonance, Critical band
The slow rise and fall in loudness heard when two tones of nearly equal frequency sound together; the beat rate equals the difference between the two frequencies. On a plate or liquid, two close drive frequencies make patterns pulse or swap at the beat rate. Binaural beats, one tone per ear, are a perceptual effect; evidence for claimed health benefits is inconclusive.
See Interference, Frequency
A family of mathematical functions that describe the radial part of vibration in circular geometry. The modes of a circular membrane or plate are built from Bessel functions, and the radii at which nodal circles appear are set by where those functions cross zero. They are the reason circular Chladni figures and drumhead patterns look the way they do.
An illusion heard on headphones when each ear gets a slightly different tone, say 520 and 530 Hz: the brainstem combines them into a 10 Hz throb. Products claim the throb pulls brainwaves to a chosen band. A 2023 systematic review of fourteen studies found five in favour, eight against and one mixed, and called the evidence inconclusive.
The science of how animals, including humans, produce, transmit and hear sound, from bat echolocation above 100 kHz to elephant rumbles near 15 Hz that travel through the ground. It provides real examples of vibration carrying information through bodies and substrates, a useful corrective to vaguer claims about 'vibrational' communication.
A property of materials whose refractive index depends on the polarisation and direction of the light, such as calcite and stressed plastics. Between crossed polarising filters a birefringent object shows vivid colour fringes that map its internal stress, a technique called photoelasticity. Vibrating acrylic vessels and films can be imaged this way.
The amount of data used per second of video, usually in megabits per second. Higher bitrates preserve fine detail and smooth gradients; lower ones shrink files but introduce artefacts. Variable bitrate spends more data on busy frames, which suits cymatics footage where a whole surface of fine ripples changes every frame.
The final stage of a draining soap film, where it is so thin that reflections from its two faces cancel and it appears black against a dark background. Wikipedia gives common black films as around 50 nm thick and Newton black films as around 4 nm. On a vibrating film the black region often marks where bursting is imminent.
Parts of the body do have measurable mechanical resonances: a seated torso around 3 to 6 Hz, a standing body near 12 Hz, the eyeball about 18 Hz, the chest wall 18 to 41 Hz according to a 2025 meta-analysis of 96 studies, with wide variation by posture and method. These are engineering figures for vibration exposure, not evidence that any musical frequency 'tunes' an organ.
See Infrasound, Vibrotactile perception, Vibroacoustic therapy
How the edges of a plate, membrane or vessel are held, which decides which modes are possible and at what frequencies. A membrane fixed all round must have a node at its rim; a plate held only at its centre has free edges and a node at the mount. Change the mounting and the same plate gives different figures.
See Plate, Node, Normal mode
The original way to excite a Chladni plate: a violin bow is drawn firmly across the plate's edge until it rings at one of its resonances, and the sand rearranges. Where you bow, and where you touch the edge with a finger to damp it, selects which mode sounds. It is quick and needs no electronics, but a driver gives repeatable frequencies.
Named ranges of rhythmic electrical activity measured on the scalp: delta about 1 to 4 Hz (deep sleep), theta 4 to 8 Hz (memory), alpha 8 to 12 Hz (relaxed wakefulness, eyes closed), beta 13 to 30 Hz (movement and thinking) and gamma above 30 Hz (attention and cognition). They are statistical descriptions of EEG, not frequencies you can play and expect the brain to copy.
The idea that brain rhythms follow a flickering light or pulsing sound, and that a desired mental state can be induced this way. Some specific effects are being researched seriously, including 40 Hz stimulation and delta-rate sound during sleep, but the broad commercial claims run far ahead of the evidence.
See Binaural beats, Isochronic tones, 40 Hz gamma stimulation
Cymatics done on a soap film or bubble instead of a plate or dish. A film on the end of a tube, or a free bubble near a speaker, vibrates with the sound; lower frequencies raise three-dimensional shapes while higher ones give flat swirling designs, and the film's changing thickness shows as interference colour.
See Thin-film cymatics, High-performance bubble, Spherical cymatics
Comparing an instrument's readings against a standard of known accuracy, and correcting them where needed; proper calibration is traceable back to a national standard. For a cymatics rig it means confirming that the frequency the generator claims is the frequency it delivers, and that a level meter reads true.
A short surface wave on a liquid whose restoring force is surface tension rather than gravity; on water this means wavelengths below roughly 1.7 cm. The fine ripples on a ringing wine glass, and the small cells of high-frequency water cymatics, are capillary waves, so adding a surfactant or changing the liquid alters their size and speed.
The bright, sharp-edged pattern formed where a curved reflecting or refracting surface concentrates light rays: the shifting web on the floor of a swimming pool, or the cusp of light inside a drinking glass. A vibrating water surface projects caustics onto a screen below, which is one way to record ripples.
The bright, shifting web of light formed where rays reflected or refracted by a curved surface bunch together, as on the floor of a swimming pool. A rippled water surface lit from above or below throws caustics onto any surface beneath or behind it, and these often show a cymatic pattern more clearly than the water itself.
A logarithmic unit for very small pitch differences: 100 cents make a semitone and 1,200 make an octave. Trained listeners can distinguish differences of around five or six cents in favourable conditions. Cents are the natural way to describe how far a tuning such as 432 Hz sits from the 440 Hz standard (about 32 cents flat).
The pattern formed when sand or salt is sprinkled on a vibrating plate: the grains are shaken off the moving regions and collect on the nodal lines, drawing the still lines of the mode being excited. Ernst Chladni published the method in 1787, bowing metal plates; today plates are usually driven by a loudspeaker or shaker at chosen frequencies.
A flat metal or composite plate, usually fixed at its centre, that is set vibrating so a sprinkled tracer such as sand reveals its vibration pattern. Chladni bowed his plates by hand; since the twentieth century a loudspeaker-style driver fed by a signal generator has been the usual way to hold the plate at one exact frequency.
A packaged classroom or studio set for Chladni figures: typically a 24 cm square plate and a 24 cm round plate, a bottle of extra-fine sand and a shaker, with a mechanical wave driver and sine generator either included or bought separately. Newer consumer versions build in Bluetooth and an app of preset frequencies.
An empirical rule giving the frequencies of a circular plate's modes from the number of nodal diameters (m) and nodal circles (n): frequency is proportional to (m + 2n) raised to a power, with the constants depending on the plate. It is a useful guide to where the next pattern will appear when sweeping a circular Chladni plate.
The natural vibration patterns of a stretched circular skin such as a drumhead, each labelled by two numbers: how many nodal diameters cross it and how many nodal circles ring it. Their frequencies are not harmonic, and modes with at least one nodal diameter come in degenerate pairs that can combine into rotating patterns.
An amplifier whose output transistors act as switches rather than as linear gain devices, producing a pulse train that a low-pass filter turns back into audio. Because the devices are either fully on or fully off, efficiencies well over 90 per cent are common, so class-D amplifiers run cool and small — useful in portable and enclosed rigs.
What happens when an amplifier is driven beyond its maximum output: the peaks of the waveform are flattened off. In the frequency domain the signal moves towards a square wave and gains strong high harmonics. A clipped sine no longer excites a single mode cleanly, so the pattern on the plate blurs.
See Gain, Distortion, Square wave
A 0 to 100 score of how faithfully a light source shows the colours of objects compared with a reference such as daylight. Many LEDs have spiky spectra and score poorly, especially on saturated reds. For camera work the Television Lighting Consistency Index (TLCI) uses a camera rather than a human observer as its reference.
A way of describing the colour of nominally white light by comparing it with a glowing black body, expressed in kelvin. Wikipedia gives a candle at about 1,850 K, an incandescent lamp at about 2,400 K and daylight at 6,500 K. Confusingly, low kelvin values look warm and orange while high values look cool and blue.
Visible damage left by lossy compression: blocky flat patches where quantisation is coarse, ringing around sharp edges, posterised bands in gradients, and mosquito noise shimmering around detail. Smooth colour gradients on a soap film and fine sand grain are exactly the content that compresses worst.
See Bit rate, H.264, Moiré pattern
Visible errors left by lossy video compression when the bitrate is too low: square blocks, stepped banding in smooth gradients, ringing and shimmering mosquito noise around edges. Fine repeating ripples and soft colour gradients on water or film are exactly the content codecs handle worst, so they need generous bitrates or 10-bit encoding.
See Bit rate, Video codec, Moire
Consonant intervals sound smooth and settled, dissonant ones rough or tense. Simple frequency ratios tend to be consonant; Helmholtz traced roughness to beating between nearby partials within the ear's critical band. What counts as dissonant also shifts with culture and period, so a plate figure cannot by itself declare a chord 'harmonious'.
See Interval, Beats, Harmonic series
The connection by which vibration passes from one part of a system to another: from loudspeaker to air to plate, from shaker to vessel to liquid, or between two plates on a shared frame. Weak coupling loses energy and blurs patterns; strong coupling lets one resonance pull another off frequency. Mounting details are largely questions of coupling.
Faraday's own word for the fine rippled texture he saw on liquids resting on vibrating plates in 1831, caused by capillary waves. Lord Rayleigh kept the term in his 1883 paper on the crispations of fluid on a vibrating support. It survives as a period name for what are now called Faraday waves.
The bandwidth of the ear's internal filter around a given frequency, a concept introduced by Harvey Fletcher in 1933. Tones falling inside the same band are not fully separated: they mask one another and beat, producing the roughness heard as dissonance. The band widens as frequency rises.
The CymaScope makers' name for a single photographed sound pattern on water, presented as a geometric image. Its form depends mainly on the frequencies in the sound and the diameter of the cuvette. The claim that the pixel is the size of a water molecule is marketing language; the picture is a Faraday-wave surface lit and photographed.
See CymaScope, Faraday waves
A commercial instrument developed in the UK by acoustics engineer John Stuart Reid that channels sound into a shallow fused-quartz cuvette of pure water, lights the surface and photographs the resulting pattern, which the makers call a CymaGlyph. It is a refined speaker-and-dish rig; the site's claims that images carry therapeutic infrared modulations are not established science.
A large hand-forged bronze singing bowl, about 43 cm across, sold by Peter Hess and Kymat, that is filled with water and struck gently with a mallet so standing waves and patterns appear on the surface. It is the acoustic, no-electronics version of a speaker dish; the maker's claims about calming and concentration are wellness marketing rather than measured effects.
See Kymat, Cymatic vessel
A loose phrase with two uses: a device built to render sound visible in real time, such as the commercial CymaScope, which imprints tones on a water surface, or a musical instrument coupled to a plate or vessel so that playing it drives a visible pattern. Neither sense implies anything beyond ordinary resonance; the value is in what the image shows about the sound.
Any container of liquid built or chosen to be vibrated for cymatics: a bottle cap, a petri dish, a bronze bowl, or the fused-quartz cuvette in a CymaScope. Its diameter, depth and rim shape set which standing-wave patterns can fit, so changing the vessel changes the pictures even at the same frequency.
See Speaker-mounted dish, Dish and membrane choices, Cymatic bowl
The practice of making sound and vibration visible by driving a plate, membrane or dish of liquid and watching particles, paste or the liquid surface settle into patterns. The word was coined in 1967 by the Swiss physician Hans Jenny from the Greek kyma, meaning wave. The physics is standard modal vibration; some of the claims attached to it are not.
See Hans Jenny, Kymatik, Chladni plate
Projecting real-time plate, water or liquid-film patterns as part of a concert. Björk used bass-driven cymatic projections on her Biophilia tour, and cellist Laura Ritchie has performed 'Resonance' for solo cello with synchronised cymatic images for each pitch. The practical challenge is that stable figures need sustained single frequencies, which most music does not supply.
The best-known example is Nigel Stanford's 'Cymatics: Science vs. Music' (2014), which pairs a Chladni plate, a speaker dish of liquid, a hose pipe filmed at a matched frame rate, ferrofluid, a Rubens tube and a Tesla coil with a synthesiser score. Unusually, the experiments were filmed first and the music written to fit them. Other examples include The Glitch Mob's 'Becoming Harmonious'.
See Cymatics in live performance, Cymatic instrument, Frequency sweep
Visible vibration has become a stage and screen device. Björk used cymatic projections on the Biophilia tour, which opened at the Manchester International Festival on 30 June 2011; Nigel Stanford's video Cymatics, published in November 2014, built a track around visible-sound experiments; the Eurovision Song Contest 2022 logo was based on cymatics.
The loss of vibration energy to friction, air, sound radiation or internal heating, which makes a free vibration die away. Heavier damping gives weaker, broader resonances and sluggish patterns; light damping gives sharp, clear ones. Viscous liquids and rubber mountings add damping; a thin metal plate hanging freely has little.
Lighting arranged so that no direct light reaches the camera and only light scattered or reflected by the subject is seen, giving bright detail on a black background. Borrowed from microscopy, it is a standard way to photograph water ripples, powder on a plate or bubble films without the lamp itself appearing in shot.
See Backlight, Raking light, Ring light
A logarithmic unit for comparing two quantities, used because sound levels span an enormous range. Adding 10 dB means ten times the power; adding 6 dB roughly doubles the amplitude; adding 3 dB doubles the power. On its own a decibel figure means nothing until you know the reference, which for sound in air is usually 20 micropascals.
When two or more distinct modes share the same natural frequency, which happens routinely in symmetric shapes such as circles and squares. Because they can be excited together in any proportion, the pattern seen at that frequency depends on where the plate is driven or touched, and slight asymmetries split the pair into two close frequencies.
The range of distances that appear acceptably sharp in an image. It shrinks as the aperture opens, as focal length grows, and dramatically as the camera gets close to the subject, so a macro shot of a bubble may hold only a sliver of the surface in focus. Stopping down helps but costs light.
A glass filter coated with many thin layers of differing refractive index so that it reflects some wavelengths and transmits others by interference rather than absorption. Dichroics run cool and are used in stage lighting and in laser projectors, where they combine separate red, green and blue beams into one.
A surface with a fine regular structure that spreads light into separate beams at angles that depend on wavelength, so white light fans out into spectra. A CD's spiral of pits does this, as does holographic wrapping film. Gratings sit behind the rainbow flares that appear when lasers or bright LEDs hit textured or ruled surfaces.
Reflection from a rough or matte surface that scatters light over a broad range of directions, so the surface looks evenly lit from any viewpoint and shows no mirror image. Sand or salt on a Chladni plate reflects diffusely, which is why it photographs cleanly under almost any lamp, unlike water or film.
The circuit that turns a stream of numbers into a varying voltage. Resolution, in bits, sets how many output levels it can produce; an 8-bit DAC has 256. Every computer, phone or DDS module driving a cymatics rig has a DAC sitting between the software and the amplifier.
A way of generating waveforms digitally from a fixed reference clock. A numerically controlled oscillator steps through a stored waveform, and a digital-to-analogue converter turns the result into a voltage. DDS gives very fine, repeatable frequency setting, which is why cheap DDS modules and benchtop generators built around them are common in cymatics rigs.
See Signal generator, Digital-to-analogue converter, Oscillator
The practical decisions behind a rig: a rigid plate, a stretched membrane such as a drumhead or balloon, or a dish of liquid; round, square or otherwise; how large; and how it is fixed. Boundary conditions shape the modes, so a centre-clamped plate, an edge-clamped membrane and a free water surface give different pattern families.
The rule linking a wave's frequency to its wavelength in a given medium. For plates and liquid surfaces it is not a simple proportion: on water, short capillary waves travel faster than slightly longer ones, and bending waves in a plate speed up with frequency. This is why pattern size does not scale simply with drive frequency.
Any alteration of a waveform's shape between input and output. Harmonic distortion adds whole-number multiples of the original frequencies; intermodulation distortion adds sum and difference tones. Total harmonic distortion sums the harmonic content as a percentage of the fundamental. It matters in cymatics because a distorted sine is no longer one frequency.
The hardware or software that generates DMX values. Channels are set with faders, wheels or encoders, and states are stored as cues that can be recalled in sequence. For a cymatics installation it is what ties light changes to a soundtrack or to a change of drive frequency.
See DMX512, Art-Net, TouchDesigner
The standard control protocol for stage lighting. One DMX universe carries 512 channels, each an 8-bit value from 0 to 255, sent at 250 kbit/s down a daisy-chained bus that should be terminated at the far end. The standard specifies 5-pin XLR connectors, although 3-pin is widespread in practice.
A cymatics plate mounted directly on a loudspeaker, exciter or mechanical wave driver so it can be held at any chosen frequency. Since the twentieth century it has become more common to place a loudspeaker driven by an electronic signal generator over or under the plate rather than bowing it, which makes modes repeatable.
See Mechanical wave driver, Chladni plate, Speaker-mounted dish
A note or chord held continuously under a piece, as in bagpipes, the Indian tanpura and much minimalist and ambient music since the 1960s. Because a drone is a fixed frequency held for a long time, drone-based music is the easiest kind to pair with cymatics: the medium has time to settle into a stable figure.
The fraction of each period a signal spends switched on, expressed as a percentage or a ratio. A true square wave has a 50 per cent duty cycle. For a strobe the duty cycle sets flash length: a short one gives a crisper frozen image but a dimmer one.
Holding a single fixed sine frequency for a stretch of time rather than sweeping. In vibration testing a sine dwell applies one tone at set amplitude and duration, and a resonance dwell holds it at the specimen's natural frequency. In cymatics a dwell is what lets a pattern fully form, stabilise and be photographed.
In physics, two coupled oscillators settling into a shared rhythm, as Huygens saw with pendulum clocks on one beam in 1665. Brains can follow a flickering light or a steady click in EEG, which is where 'brainwave entrainment' comes from. The demonstrated effect is a following response; the claim that it can dial in a chosen mental state is far less well supported.
See Brainwave bands, Binaural beats, 40 Hz gamma stimulation
A description of how a sound or control value changes over time. The standard four-stage form is ADSR: attack, decay and release are times, sustain is a level. Envelopes matter in cymatics because a struck or ramped drive tone needs time to settle before the pattern is stable enough to photograph.
The tuning used on most modern instruments, which divides the octave into twelve equal semitones each a ratio of 2 to the power 1/12, about 1.0595. It lets music move freely between keys at the cost of slightly impure intervals: the fifth is 2 cents sharp of pure, the major third almost 14 cents sharp.
German physicist and musician, 30 November 1756 to 3 April 1827, sometimes called the father of acoustics. In his 1787 book Entdeckungen über die Theorie des Klanges he showed that bowing a sand-covered metal plate makes the sand gather on nodal lines. Napoleon later offered a prize for a mathematical explanation.
A transducer with a voice coil but no cone, bonded to a panel or object so that the object itself radiates. Distributed mode loudspeakers use moving-coil or piezoelectric exciters placed to suit the panel's own resonant modes. In cymatics they let you drive a plate, sheet or vessel directly rather than through the air.
See Voice coil, Tactile transducer, Piezoelectric transducer
The amount of light that reaches the sensor for one frame, set by aperture, shutter speed and ISO working together. Too much blows out highlights to featureless white; too little crushes shadows to black. Bright specular glints on water and film clip easily, so the exposure is often set for the highlights and the rest lifted later.
See Shutter speed, ISO, Depth of field
Which regular lattice Faraday waves form on a shaken liquid. Experiment and theory find that high-viscosity liquids favour parallel stripes, while low-viscosity liquids give squares at higher frequencies, where surface tension dominates, and hexagons or eight-fold patterns at lower frequencies, where gravity also matters. Driving with two frequencies at once can produce superlattice patterns.
Standing waves that appear on the surface of a liquid when its container is shaken up and down hard enough, first described by Michael Faraday in 1831. Above a threshold amplitude the flat surface becomes unstable and breaks into stripes, squares, hexagons or more complex patterns, usually oscillating at half the driving frequency. Most water and thin-film cymatics is Faraday waves.
See Parametric excitation, Subharmonic, Faraday pattern selection
Nonlinear standing waves that appear on a liquid when its container is shaken vertically hard enough. Above a threshold the flat surface becomes unstable and forms stripes, squares, hexagons or more complex arrangements, oscillating at half the driving frequency. Every pattern seen in a dish on a speaker is a Faraday wave.
Michael Faraday's report in the Philosophical Transactions of the Royal Society, volume 121, pages 299 to 340, titled On a peculiar class of acoustical figures; and on certain forms assumed by groups of particles upon vibrating elastic surfaces. It records powders behaving unlike Chladni's sand and, in an appendix, the surface ripples now called Faraday waves.
An algorithm that computes the discrete Fourier transform in roughly n log n operations rather than n squared. Cooley and Tukey published the widely used version in 1965, having independently rediscovered a method Gauss used in 1805. It is what makes real-time spectrum and spectrogram displays practical.
A dark liquid of nanoscale magnetic particles in a carrier fluid, roughly 5 per cent solids, 10 per cent surfactant and 85 per cent carrier. In a strong vertical magnetic field it spikes into regular peaks. It is often filmed alongside cymatics, but the spikes come from magnets, not sound, so it is a related visual rather than cymatics.
The everyday skill of sweeping a signal generator slowly until the plate or dish suddenly answers and the tracer snaps into a clean figure. Patterns appear only near resonant frequencies, so adjustments must be made slowly; then the frequency is held (dwell) and the level trimmed while the pattern settles.
See Frequency sweep, Dwell, Resonance
Flashing light can provoke seizures in people with photosensitive epilepsy. Sensitivity varies between individuals, so no single rate is universally safe; reported symptoms cluster roughly between 15 and 70 Hz. Accessibility guidelines cap flashing at three times in any one second, and many commercial strobes are factory-limited to around 10–12 Hz.
A visible fluctuation in the brightness of a light source, caused by mains frequency, pulse-width dimming or unstable supplies. Wikipedia puts the eye's threshold near 90 Hz, but cameras catch far faster flicker as rolling bands or pulsing brightness depending on shutter speed and frame rate, so LED rigs should be filmed with matched settings.
Combining several photographs taken at different focus distances into one image with greater depth of field than any single frame. It suits static subjects such as a finished sand pattern on a plate, but not a moving film or liquid surface, because the frames must line up.
Vibration kept going by a continuous external drive, such as a loudspeaker, electromagnetic shaker or motor, so that the object moves at the driving frequency whatever its own natural frequencies. Most cymatics rigs use forced vibration, sweeping the drive frequency until it coincides with a resonance and a pattern appears.
The mathematics that turns a signal over time into the frequencies it contains, following Joseph Fourier's 1822 claim that any function can be built from sines. The FFT, popularised by Cooley and Tukey in 1965, is the fast algorithm behind every spectrum display, tuner and pitch-correction plug-in, and behind the analysers used to study cymatic rigs.
See Spectrum, Spectrogram, Sine tone
How many images a camera records or a screen shows each second. Cinema uses 24, European television 25 or 50, and much online video 30 or 60. When a vibration frequency is near a multiple of the frame rate, the pattern can appear frozen or crawling on video even though it is moving fast.
Vibration that carries on by itself after a single disturbance, such as a struck plate or a tapped bowl, ringing at its natural frequencies and fading through damping. In cymatics it is the response you get from a tap or a bow stroke, as opposed to the sustained drive of a loudspeaker or shaker.
How many complete cycles of a vibration or wave happen each second, measured in hertz (Hz); 100 Hz means a hundred cycles per second. Frequency is the main control in cymatics: raising it generally shortens the wavelength and produces finer, more intricate patterns on a given plate or liquid.
See Period, Wavelength, Amplitude
An evoked electrical response, recorded from the brainstem, that phase-locks to a periodic sound. Worden and Marsh named it in 1968 and it is routinely used in auditory research. It shows that the auditory pathway tracks a stimulus, which is not the same thing as the whole brain adopting that rhythm.
How strongly a system passes or reproduces each frequency, measured by feeding it sweeps, noise or impulses and recording the output. A 'flat' loudspeaker treats all frequencies alike; real drivers, plates and vessels do not, and their peaks are the resonances a cymatics rig relies on. Knowing the response of your speaker tells you which tones will actually reach the medium.
The distribution of a signal's power across frequency: which frequencies are present and how strong each is. A spectrum analyser shows it live, which is how you check that a driver is actually producing the tone you asked for rather than distortion products and rattle.
A signal whose frequency glides smoothly from a start to an end value, linearly or logarithmically, at constant amplitude. In audio measurement it maps how a system responds across a range; on a cymatics rig a slow sweep is how you discover where the resonances lie before choosing frequencies to dwell on.
See Finding a mode, Dwell, Modal testing
The fraction of light a water or glass surface reflects depends on the angle at which light meets it: only about four per cent for glass viewed head-on, rising steeply towards grazing angles. At Brewster's angle the reflected light is entirely polarised in one plane, which is what a polarising filter exploits.
The lowest frequency at which an object vibrates, or the lowest component of a periodic sound, which normally sets the pitch we hear. On a plate the fundamental gives the simplest Chladni figure, with the fewest nodal lines; higher modes add more lines and finer detail.
How much a stage multiplies a signal, given as a ratio or in decibels — 20 log of the voltage ratio. A gain control is less a volume knob than a setting for how hard the next stage is driven. Gain set too high is the usual cause of clipping in a cymatics signal chain.
See Clipping, Power amplifier
The non-linear encoding of brightness used throughout imaging, roughly a power of 0.45 on capture and 2.2 on display. Human vision separates dark tones better than bright ones, so gamma spends more of the available data where differences will actually be seen.
A sensor that exposes every pixel at the same instant, so there is no skew, wobble or partial-flash banding. Common on CCDs and available on some CMOS sensors, usually at the cost of sensitivity or money. Worth having when filming strobed or fast-vibrating subjects.
A colourless, sweet, very viscous liquid (about 1.4 Pa·s at 20 °C) that mixes with water in any proportion and absorbs moisture from the air. Glycerol-water mixtures give a smooth range of viscosities with no elasticity, which is why fluid-dynamics labs use them for Faraday waves and why Jenny vibrated glycerine on diaphragms.
See Viscosity, Faraday waves
A wave on a liquid surface in which gravity, not surface tension, pulls the displaced liquid back towards level; ocean waves and sloshing in a bowl are gravity waves. On water they dominate at wavelengths longer than a couple of centimetres, so low-frequency cymatics in large vessels sits in this regime. Not to be confused with gravitational waves in spacetime.
See Capillary wave, Liquid surface modes, Dispersion relation
Two points meant to sit at the same ground potential but joined by more than one conducting path, forming a loop that picks up stray magnetic fields from nearby mains wiring. In audio the induced current is heard as hum. Fixes include isolation transformers, balanced connections and lifting a cable shield at one end.
The block-based video codec most of the web still runs on, finalised in May 2003 as H.264/AVC and reported in 2024 as used by around 79 per cent of video developers. Patents are licensed through a pool. Files are larger than newer codecs at equal quality, but playback is close to universal.
The successor to H.264, offering roughly 25 to 50 per cent smaller files at the same quality. It is encumbered by several patent pools, and browser support arrived late and unevenly, so it is more common in camera recordings and Apple devices than as a universal web format.
See Video codec, AV1, Bit rate
Swiss physician and natural scientist, born in Basel on 16 August 1904, died in Dornach on 23 June 1972, who coined the word cymatics. He used crystal oscillators and his tonoscope to vibrate plates and membranes carrying powders, fluids and pastes, and published the results in Kymatik (1967, 1972). His anthroposophical framing colours some interpretations.
A frequency that is a whole-number multiple of a fundamental: for a 100 Hz fundamental the harmonics are 100, 200, 300 Hz and so on, with the fundamental counted as the first. Strings and air columns vibrate in harmonic series; plates, bells and membranes generally do not, which is why their patterns do not line up with musical intervals.
The set of frequencies at whole-number multiples of a fundamental: f, 2f, 3f, 4f and so on. Strings and air columns produce partials close to this series; bells, drums and plates produce inharmonic partials that do not line up, which is why a struck Chladni plate does not ring with a clear musical pitch.
A mechanical drawing device using two or more pendulums, one moving the pen and another the paper, so decaying swings combine into Lissajous-like curves. It appeared in the mid nineteenth century and peaked in popularity in the 1890s, often credited to Hugh Blackburn. It visualises frequency ratios rather than sound itself.
Video that carries a wider range of brightness and colour than standard formats, so highlights can be far brighter and shadows deeper on a capable display. The main formats are HDR10, Dolby Vision and HLG, using the PQ or HLG transfer curves in place of ordinary gamma. Glints on water and laser lines benefit; most web players still show SDR.
See Log profile, Exposure
Humans nominally hear from 20 Hz to 20 kHz, most sensitively between about 2 and 5 kHz; the upper limit falls with age and most adults cannot hear above 16 kHz. Dogs reach 45 kHz, bats 200 kHz, elephants down to 16 Hz. Much of what a cymatics rig does, above 20 kHz or below 20 Hz, is invisible to the ear but not to the medium.
Cochlear hair cells do not regrow, so loud-sound damage is permanent. NIOSH recommends no more than 85 dBA averaged over eight hours, halving allowed time for every 3 dB more. Ringing or muffled hearing after a session is a warning sign. Cymatics rigs are often run loud and close, so wear earplugs or earmuffs rated for 10 to 40 dB of attenuation.
NIOSH recommends keeping worker noise below the equivalent of 85 dB(A) over eight hours, using a 3 dB exchange rate that halves the allowed time for every extra 3 dB. OSHA requires hearing protection above a 90 dB(A) daily average and caps impulse peaks at 140 dB. EU rules act at 80 and 85 dB(A).
The low-pitched resonance of air in a cavity with a narrow opening, like the note from blowing across a bottle: the plug of air in the neck bounces on the springy air inside. The frequency depends on cavity volume, neck size and the speed of sound. Any partly closed vessel in a cymatics rig has one, and it can colour or boost the drive.
See Resonance, Speed of sound
The SI unit of frequency: one hertz is one cycle per second. Adopted in 1960 in place of 'cycles per second' and named after Heinrich Hertz, who first demonstrated radio waves. In cymatics the number you dial into a signal generator is a frequency in hertz, and each pattern on a plate or in a dish belongs to a particular one.
See Pitch, Sine tone, Audio frequency
Video or stills carrying a wider span of brightness than standard, requiring at least 10 bits per sample and a transfer function such as PQ, used by HDR10, or HLG, which stays backwards compatible with standard displays. It holds highlight detail that standard range clips, though most web delivery is still SDR.
A soap-bubble mixture formulated to be tough and long-lived, with a thin, flexible film that survives being vibrated. Because such bubbles last, a speaker can drive them into ever-changing three-dimensional shapes and colour swirls, which is what makes spherical, thin-film cymatics practical for filming rather than a lucky moment.
Recording at far more frames per second than normal, then playing back at a standard rate so that fast events unfold slowly. Wikipedia defines a high-speed camera as exceeding 250 frames per second or exposures shorter than 1/1000 s. Higher rates need much more light and usually cost resolution, which is why lit rigs matter.
The opposition a circuit or transducer presents to alternating current, measured in ohms. Unlike plain resistance it has both magnitude and phase and it varies with frequency. Power into a load goes up as impedance falls, so the same amplifier delivers roughly twice the watts into 4 ohms as into 8.
Sound below about 20 Hz, produced by weather, volcanoes, surf, whales and elephants, and by engines and wind turbines. It is not heard as pitch but at high levels can be felt in the body. Claims that it reliably causes nausea, dread or the 'brown note' are not supported; a widely cited 2003 concert study found only that some listeners reported unease.
What happens when two or more waves overlap: where they are in step they reinforce each other (constructive interference) and where they are out of step they cancel (destructive interference). Standing waves, and so all cymatic nodal patterns, are interference between a wave and its own reflections from the edges.
See Superposition, Standing wave, Phase
One of the alternating bright and dark bands formed where two coherent waves overlap: bright where crests coincide, dark where a crest meets a trough. Fringes are the readable output of most interference methods, from Young's double slit to the colour bands drifting down a soap film.
Alternating bright and dark bands formed where two coherent light waves overlap: where they are in step they add, where they are out of step they cancel. Young's double-slit experiment is the classic example. The colour bands on soap films, Newton's rings and laser speckle are all interference fringes of one kind or another.
The difference in pitch between two notes, expressed physically as a frequency ratio: the perfect fifth is 3:2, the fourth 4:3, the major third 5:4 and the octave 2:1. Cymatics demonstrations that compare 'harmonious' and 'discordant' figures are comparing two frequencies whose ratio is simple or not.
The reverse of the usual Chladni figure, in which very fine powder gathers at the antinodes instead of the nodes. Faraday studied it in 1831 using lycopodium spores; the cause is air currents (acoustic streaming) set up by the vibrating plate. At low vibration levels streaming wins and powder goes to antinodes; at higher accelerations grains bounce and settle on nodes.
The property of a surface whose colour appears to change with the angle of view or of illumination. It comes from interference of light in thin films or fine microstructures rather than from dye. Bubbles, oil slicks and vibrating soap films are iridescent, which is why the same patch shows different colours to a camera moved a few degrees.
The camera's sensitivity setting, defined for digital cameras by the standard ISO 12232. Raising it amplifies the sensor signal so darker scenes can be shot with faster shutters, at the cost of visible noise rather than film grain. Dark-field and laser shots often push ISO because so little light reaches the lens.
See Exposure, Shutter speed
A single tone switched sharply on and off at a regular rate, played to both ears, and marketed for brainwave entrainment alongside binaural and monaural beats. There has been very little research on any health benefit; the claims outrun the evidence. Because the pulse rate is audible and distinct, they are at least easy to pair with a strobe or a pulsing cymatic display.
English acoustics engineer, founder of Sonic Age Ltd and inventor of the CymaScope, who turned to cymatics after experiments on the resonance of the sarcophagus in the Great Pyramid in 1997. He lectures widely on sound therapy and what he calls cymatic science; several of his wider claims about sound and healing go beyond the evidence.
Tuning intervals to small whole-number ratios drawn from the harmonic series, so that they sound without beats. It is what singers and string players drift towards by ear. Keyboards abandoned it because stacked pure fifths do not close on the octave (the Pythagorean comma), and equal temperament took over.
A transparent tube with fine powder inside, a sound source at one end and a movable piston at the other, devised by August Kundt in 1866. At resonance the powder gathers in piles at the nodes of the standing wave; the pile spacing is half a wavelength, and wavelength times frequency gives the speed of sound. An early cousin of cymatics.
A German art project for cymatics, plant-data music and audiovisual sound installations, known for the Sonic Water installations, live performances, fine-art prints and a Cymatic Bowl developed with Peter Hess. It has exhibited at Art Basel Hong Kong, Milan Design Week and Nuit Blanche Paris.
See Sonic Water, Cymatic bowl
The German title of Hans Jenny's two-volume book, first published by Basilius Presse in Basel in 1967 with a second volume in 1972, the year he died. It documents in photographs how sound made powders, fluids and pastes form ordered patterns, and is where the word cymatics first appeared.
See Hans Jenny, Cymatics
Bouncing a laser off a small mirror glued to a speaker cone, a balloon stretched over a tube, or a vibrating surface, so the beam traces the motion on a wall. Two mirrors on two speakers at right angles draw Lissajous figures; a single mirror on a plate magnifies its wobble. First-surface mirrors and low frequencies give the cleanest lines.
The looping figure traced when a beam is moved by two perpendicular oscillations at different frequencies; the ratio of the frequencies sets the number of lobes and the phase sets its skew. Studied by Bowditch in 1815 and Lissajous in 1857, the pattern appears whenever a laser is bounced off mirrors on two vibrating surfaces or tuning forks.
A show projector steers a laser beam with two mirrors mounted on fast galvanometers, one for horizontal and one for vertical, redrawing a figure so quickly that the eye sees a continuous line. Wikipedia quotes scan speeds of roughly 8k to 60k points per second, and RGB units mix three lasers through dichroic mirrors to produce colour.
A device that steers laser beams with fast mirrors to draw shapes on a screen or in haze. Drawing is vector-based rather than raster, scanning speed is quoted in kilopoints per second, typically 8k to 60k, and the beam is blanked while the mirrors reposition. ILDA sets the common control standards.
The grainy, glittering texture seen wherever a laser lands on a rough surface, caused by random interference between scattered coherent waves. It depends on the viewing geometry and lens aperture, so cameras record it differently from the eye. Speckle is a nuisance in laser-lit cymatics footage but is also a sensitive indicator of surface motion.
A circle of individually addressable LEDs on one board, chained so a single data pin controls all of them. Adafruit's 12-LED NeoPixel ring, for instance, runs at 5 V with about 18 mA constant-current drive per element. Rings are useful in cymatics for lighting a dish evenly and colouring the image by angle.
The natural ways a liquid with a free surface can slop back and forth in a vessel, set by the vessel's shape and the liquid's depth and restored by gravity and surface tension. Vessel geometry therefore matters in liquid cymatics: round, square and irregular vessels have different mode families, and the meniscus at the wall can seed patterns from the edge inward.
The looping figure traced when two sinusoidal motions at right angles are combined, on an oscilloscope in X-Y mode, a harmonograph, or a laser bounced off two vibrating mirrors. The shape gives away the frequency ratio and the phase difference; the figure closes into a fixed loop only if the ratio is a whole-number fraction.
A camera recording setting that encodes brightness logarithmically to keep detail in both highlights and shadows. Footage looks flat and washed out until it is graded, usually through a lookup table (LUT) that maps it back to a normal display look. It helps hold both dark water and bright reflections in one shot.
See White balance, HDR, Exposure
A wave in which the medium moves back and forth along the direction the wave travels, as a series of compressions and rarefactions. Sound in air and in water is longitudinal. The powder piles in Kundt's tube mark the nodes of a longitudinal standing wave in air.
The perceived strength of a sound, distinct from measured sound pressure. Hearing is most sensitive around 2 to 4 kHz and much less so at low frequencies, which equal-loudness contours map out; the phon and sone are units built on them. A 40 Hz tone that drives a dish of water visibly can sound surprisingly quiet.
An oscillator running below about 20 Hz, too slow to be heard as a pitch. Its output is used as a control signal to modulate something else — pitch, amplitude, filter cutoff, or in a rig the brightness of a light or the level of a drive tone — producing slow repeating movement.
A yellow-tan powder of dried clubmoss spores, each about 33 micrometres across, very light and strongly water-repellent. It was a traditional physics tracer for Kundt's tube and Brownian motion, and Jenny used it on plates. Being so fine it can collect at antinodes rather than nodes, and it is flammable as a dust cloud.
Close-up photography in which the subject is recorded at life size or larger on the sensor, conventionally a reproduction ratio of at least 1:1. Its difficulties are very shallow depth of field, awkward lighting with the lens close to the subject, and short working distance, all of which apply to filming bubbles and small vessels.
Noise associated with alternating-current mains, usually heard at twice the line frequency — 100 Hz where the mains is 50 Hz, 120 Hz where it is 60 Hz — plus harmonics above that. Worth identifying in a cymatics rig, because those frequencies can excite modes of their own and contaminate a clean drive tone.
Flow along a liquid surface driven by differences in surface tension, from regions of low tension towards regions of high tension. It is what keeps a soap film from draining and bursting immediately, since a stretched patch pulls in surfactant-rich liquid, and it matters for how long a bubble survives being vibrated.
A visual programming language for music and multimedia, developed and sold by Cycling '74 and originally written by Miller Puckette at IRCAM from 1985. MSP added real-time audio processing in 1997 and Jitter added video and OpenGL in 2003. It is the commercial relative of Pure Data.
See Pure Data, TouchDesigner, MIDI
A laboratory transducer, essentially a loudspeaker voice coil and magnet with a rod instead of a cone, that shakes whatever is mounted on it at the frequency fed from a signal generator. Chladni plate kits from PASCO and others mount the plate's centre on such a driver; it is the precise, adjustable replacement for the bow.
A thin, flexible sheet held in tension, such as a drumhead or a stretched latex sheet, whose restoring force is that tension. Its modes are described by Bessel functions for circles and by sine waves for rectangles, and tightening it raises every frequency. Tonoscope-style diaphragms sit somewhere between membrane and plate behaviour.
The curved edge of a liquid surface where it meets a vessel wall, concave for water in glass because the water clings to the wall. Since it is a permanent bump in the surface, the meniscus is often where Faraday waves start, and a vessel filled to the brim or given a water-repellent coating behaves differently from one with a strong meniscus.
See Surface tension, Liquid surface modes, Boundary conditions
English chemist and physicist, 22 September 1791 to 25 August 1867, best known for electromagnetic induction. In 1831 he also studied powders and liquids on vibrating plates, describing the fine ripples he called crispations and their half-frequency response. Faraday waves, the basis of all liquid cymatics, carry his name.
A whole small computer on a single integrated circuit: processor core, memory and programmable input/output together. Designed for embedded control rather than general computing, and tuned for fast, predictable response to inputs. It is the part that reads a sensor and sets a light or a drive frequency in a self-contained rig.
A standard connecting instruments, controllers and computers. It carries performance instructions — note pitch, timing, velocity — not audio, at 31,250 baud. MIDI itself contains no sound. In a rig it is a convenient way to let a keyboard or sequencer trigger drive tones, lighting cues or strobe changes.
An opaque, low-viscosity liquid often used instead of water in a speaker dish because it photographs well without a dark dye. Water with black food colouring is the other common choice. Both show the same Faraday-wave patterns; the opacity simply makes the surface relief easier to light and record.
Originally a current meter that swung a light beam with a tiny mirror, developed by Poggendorff in 1826 and refined by Kelvin in 1858. Today the name refers to the fast motor-driven mirrors in laser projectors and scanners. Glued to a speaker cone or plate, a small mirror also turns vibration directly into a wandering laser trace.
The brain hears the pitch of a fundamental even when only its overtones are present, which is why a bass line survives a small speaker or a telephone line that cuts everything below 300 Hz. It shows that pitch is computed from the pattern of harmonics, not simply read off the lowest frequency present.
The engineering method of vibrating an object with a shaker or instrumented impact hammer to measure its natural frequencies, mode shapes, modal masses and damping. Sand on a Chladni plate is the same idea done by eye: the plate is driven, and the pattern shows the mode shape without sensors.
See Mode, Resonance, Frequency sweep
One of the characteristic ways an object can vibrate, in which every part moves at the same frequency with a fixed shape of nodes and antinodes. A plate has a whole ladder of modes at rising frequencies, each with a different nodal pattern; the Chladni figure you see is the mode shape of whichever resonance you are driving.
The spatial pattern of movement belonging to a particular normal mode: which parts of the plate or surface swing up while others swing down, and where the still nodal lines fall. Sand on a plate traces the nodal lines of the mode shape; a strobed liquid surface can reveal the moving parts as well.
See Normal mode, Node, Chladni figure
A large-scale ripple pattern that appears when two fine regular patterns overlap, such as a camera's pixel grid and a closely spaced ripple field. It is a form of spatial aliasing. Moire can imitate a cymatic pattern or hide a real one, so it is worth checking against a change of zoom or camera distance.
Large-scale banding produced when two fine regular patterns overlap slightly out of step, through displacement, rotation or a difference in pitch. It appears when a sensor's pixel grid samples a fine repeating subject, or when you photograph a screen, and can easily be mistaken for a real interference pattern.
Two close frequencies mixed together before they reach the ear, so the beating is a real acoustic effect that works through speakers and with one ear, unlike binaural beats which exist only in the brain. Sold for the same 'entrainment' purposes and no better evidenced.
The clinical use of music by accredited therapists to meet emotional, cognitive and physical goals. Unlike sound healing it is regulated and studied: reviews report small to moderate reductions in depression and anxiety, though certainty is generally low and a 2025 Cochrane review found dementia evidence insufficient. Its benefits come from the music and the relationship, not from any special frequency.
See Sound healing, Sound bath
The frequency at which an object vibrates by itself after being disturbed, set by its stiffness, mass and shape. A plate or vessel has many natural frequencies, one for each mode. Driving it at or near one of them produces a large, clean response, which is why cymatic patterns appear at particular frequencies rather than at all of them.
Concentric bright and dark rings seen where a curved glass surface rests on a flat one, produced by interference in the thin wedge of air between them. Described by Robert Hooke in 1665 and studied by Isaac Newton from 1666, the same mechanism gives ringed colour bands in bubbles and in wetted glass over a cymatics plate.
A line on a vibrating plate or membrane along which the surface does not move, separating regions that swing up and down in opposite phase. Coarse tracers such as sand are thrown off the moving regions and collect on the nodal lines, so the visible pattern is a map of where the surface is still.
See Node, Antinode, Chladni figure
The arrangement of nodal lines belonging to one mode, for example a given number of nodal diameters and nodal circles on a round plate. Related modes group into families with a shared geometry, and Chladni's law notes that its exponent can change from one family of modes to another on the same object.
See Chladni's law, Mode, Chladni figure
A place in a standing wave where the medium stays still while everything around it moves. On a vibrating plate the nodes join up into nodal lines, and sand or salt is shaken off the moving areas and gathers on those still lines, which is what a Chladni figure shows.
A fluid whose viscosity changes with the force applied to it, unlike water or glycerine. Shear-thickening (dilatant) fluids such as oobleck get stiffer the harder they are stirred, so the rapid pushes of a speaker cone make them briefly behave like a solid and stand up in tendrils rather than ripple.
Behaviour in which the response is not simply proportional to the drive, so doubling the input does not double the output and superposition no longer holds. Faraday waves, pattern selection, subharmonics and acoustic streaming are all nonlinear effects; they appear only once the amplitude is large enough, which is why cymatics often needs a strong drive.
One of the natural patterns in which a plate, membrane, string or body of liquid can vibrate, with every part moving at the same frequency and in a fixed phase relation. Each mode has its own frequency and its own arrangement of nodes; a Chladni figure is a picture of one mode, or of a few that overlap.
Half the sample rate: the highest frequency a sampled system can represent without aliasing. At 44.1 kHz the Nyquist frequency is 22,050 Hz. Anything above it that reaches the converter is folded down and reappears as a false lower frequency, which is what anti-aliasing filters exist to prevent.
The interval between two tones whose frequencies are in the ratio 2:1, for example 220, 440 and 880 Hz. Notes an octave apart share a name and sound like 'the same' note at different heights, a phenomenon called octave equivalence. On a plate or in a dish, a tone one octave up does not simply double the pattern; it finds a different resonance altogether.
See Interval, Harmonic series, Pitch
A suspension of cornflour in water, roughly 1.5 to 2 parts starch to 1 part water, that flows when handled gently but stiffens under sudden force. On a large subwoofer at high level it thickens and forms standing waves, throwing up the writhing fingers seen in popular cymatics videos. Getting the water ratio right takes trial and error.
A network protocol for control messages between synthesisers, computers and multimedia devices, usually carried over UDP. Messages use a URL-style address such as /oscillator/4/frequency plus typed arguments, giving higher resolution and more flexible naming than MIDI, at the cost of more bandwidth and no agreed vocabulary between makers.
See MIDI, TouchDesigner, Art-Net
A birefringent layer in front of a camera sensor, typically two plates that spread each point into four, deliberately blurring fine detail so it cannot alias into moiré. Many recent cameras omit it for extra sharpness, which makes them more prone to moiré on finely repeating subjects.
A circuit or software object producing a periodic signal from a DC supply. Linear or harmonic oscillators, including crystal types, give near-sinusoidal output and good frequency stability; relaxation oscillators charge and discharge a capacitor to give square, sawtooth or triangle shapes, with poorer stability but simpler circuits.
An instrument that plots voltage against time, so you can see the actual shape of the signal reaching your amplifier or transducer. The timebase sets horizontal speed and the trigger holds the trace steady. Feeding two signals into the X and Y axes instead produces Lissajous figures, which show phase relationships directly.
Any frequency present in a vibrating object above its fundamental. Overtones that are whole-number multiples of the fundamental are harmonic; those that are not, as in plates, bells, cymbals and drums, are inharmonic. The first overtone is the second harmonic, a mismatch in counting that causes frequent confusion.
See Harmonic, Partial, Chladni's law
Driving a system by periodically varying one of its parameters, such as the effective gravity felt by a liquid in a vertically shaken dish, rather than pushing it directly. The response grows fastest when the parameter varies at about twice the natural frequency, which is why Faraday waves oscillate at half the shaker frequency. The Mathieu equation describes the stability thresholds.
Any one of the pure-tone components that make up a sound or vibration, including the fundamental. The word is neutral about whether the frequencies form a harmonic series, so it is the right term for the components of a struck plate or a singing bowl, whose partials are mostly not simple multiples of each other.
The spontaneous appearance of ordered structure, such as stripes, squares or hexagons, in a system driven away from equilibrium. Faraday waves and Rayleigh–Bénard convection are textbook examples studied in nonlinear physics. The regular figures of cymatics are pattern formation in this sense, governed by fluid mechanics rather than by any special property of the frequency itself.
See Symmetry breaking, Faraday pattern selection, Rayleigh–Bénard convection
The time taken for one complete cycle of a vibration, equal to one divided by the frequency; a 50 Hz drive has a period of 20 milliseconds. Strobe and camera timing in cymatics is worked out in periods, since freezing a pattern means flashing once per period or at a fixed fraction of it.
Where in its cycle a vibration is at a given moment, expressed as an angle from 0 to 360 degrees or as a fraction of a period. Two signals of the same frequency are in phase when they rise and fall together and in antiphase when one peaks as the other troughs. Strobes phased against the drive signal use this to freeze or slowly animate a pattern.
Flipping the sign of a signal — a 180-degree reversal — so peaks become troughs. Two otherwise identical signals in antiphase interfere destructively and cancel. Inverting one of two drivers is a deliberate way to change which modes a symmetrical rig will support, and an accidental fault when a speaker is wired backwards.
Deriving the strobe's flash timing from the same source as the drive signal rather than setting the two independently, so that each flash falls at the same point in the vibration cycle. The image then holds still indefinitely instead of drifting, and the phase offset becomes a control you can dial through the cycle.
A device using a material that accumulates electric charge when mechanically stressed and, by the inverse effect, deforms when a voltage is applied across it. As actuators piezos give tiny, extremely fast, precisely controllable movement. They turn up in rigs as cheap plate drivers, ultrasonic elements and contact pickups.
Noise whose power falls by 3 dB per octave, so each octave carries the same energy and it sounds more balanced to the ear than white noise, like a waterfall. It is the standard signal for tuning loudspeaker systems with a measurement microphone and analyser, and a useful check of what a cymatics rig's speaker actually delivers.
The perceptual quality that lets us call one sound higher than another. It tracks frequency closely but is a judgement made by the ear and brain, not a physical measurement: it shifts slightly with loudness, can be ambiguous for complex tones, and is absent from many percussion sounds. A signal generator sets frequency; a listener hears pitch.
A thin, stiff sheet whose restoring force comes from resistance to bending rather than from tension. Waves in a plate travel faster as frequency rises, and its mode frequencies are not harmonic. Chladni plates are plates in this sense, and their patterns differ from those of a membrane or a liquid surface of the same shape.
The direction in which a light wave's electric field oscillates, at right angles to its travel; it may be linear or circular. Light reflected from water or glass becomes partly polarised, completely so at Brewster's angle, which is why a rotating polarising filter can dim or remove the reflection of a lamp on a water surface.
A lens filter that passes light of one polarisation and blocks the rest; rotating it varies how much reflected glare from water or glass gets through. Circular polarisers are needed on modern autofocus cameras. For cymatics it lets you choose between seeing the reflected lamp on a water surface and seeing what lies beneath it.
The still image shown in place of a video before it plays or while it loads. In HTML the video element's poster attribute names an image file; if none is given, the browser shows the first frame once it arrives. Choosing a strong poster frame matters because many viewers see only that.
See Seamless loop, Video codec
The stage that raises a line-level signal to a level able to drive a loudspeaker, exciter or shaker; it sits between the source and the transducer. Its rating in watts means little on its own, because power depends on the load impedance and because continuous figures and peak figures differ by a factor of two or more.
The science of how people perceive sound: pitch, loudness, masking, localisation and the limits of hearing. Its findings are what MP3 encoding, loudness meters and hearing-safety rules are built on. It matters for cymatics because many popular claims about frequencies are really claims about perception, which psychoacoustics can test.
Representing an analogue level as a rectangular wave whose on-time fraction — the duty cycle — is varied. Because the switching device is either fully on or fully off, losses are low. It is how microcontrollers dim LEDs and how class-D amplifiers work; at low PWM frequencies it is effectively a hidden strobe.
A free, open-source visual programming environment for audio and multimedia, created by Miller Puckette in the 1990s. Objects are patched together on screen and data flows along the connections. It processes audio on the host CPU and is a common way to build a custom tone source or control layer without conventional coding.
LEDs are usually dimmed by switching them fully on and off very quickly, with the on fraction, or duty cycle, setting apparent brightness. A camera with a short exposure can catch the LED mid-cycle, giving dark bands or a pulsing image. Raising the PWM frequency well above the shutter and frame rate removes the artefact.
See Flicker, Rolling shutter, Ring light
A number describing how lightly damped a resonator is. High Q means it rings for a long time and responds strongly only within a narrow band of frequencies; low Q means it dies away quickly and responds broadly. A high-Q plate needs a precise drive frequency to show a pattern, and a small drift can lose it.
Light directed almost parallel to a surface so that any bump or ridge throws a long shadow. It is the technique conservators use to reveal texture in paintings, and the same trick makes low ridges of sand on a Chladni plate or slight standing waves on a liquid stand out clearly.
The rolling or hexagonal cells that appear in a thin layer of fluid heated from below, once the heating exceeds a threshold set by the Rayleigh number. It is not a sound phenomenon, but a useful contrast: it shows that hexagons and stripes arise from fluid instabilities in general, and heat from lamps can add such cells to a cymatics dish.
The bending of light as it crosses from one medium into another where it travels at a different speed, described by Snell's law. A curved water surface acts as a shifting lens, so a standing-wave pattern is seen as distortions of whatever lies beneath the water or as caustics projected through it.
The large response that builds up when something is driven at or close to one of its natural frequencies, so that each push arrives in step with the motion and energy accumulates. Cymatics relies on it: sweep a signal generator slowly and patterns snap into focus at resonance and blur in between.
See Natural frequency, Q factor, Damping
In physics, resonance is the large response a system gives when driven near its natural frequency, sharpened or blunted by damping. In wellness copy the same word is used loosely to mean sympathy, agreement or healing, and the two senses are often blurred. When something is said to resonate with the body, ask which system, at which frequency, measured how.
A dimensionless number comparing inertial forces to viscous forces in a flow. Low values mean smooth, orderly (laminar) motion; high values mean turbulence. It is a quick way to judge whether a liquid in a cymatics vessel will show clean wave patterns or dissolve into churning, and why thicker liquids behave more calmly.
Mixing coloured light rather than pigment: red, green and blue in equal measure make white, and pairs make cyan, magenta and yellow. Screens and RGB LEDs work this way. A ring of RGB LEDs driven from a microcontroller can therefore produce any hue at each point in the ring, and the mix reflected from water adds again in the camera.
A device claimed to destroy pathogens or cancer cells by matching their supposed resonant frequency, after the American inventor Royal Raymond Rife (1888-1971). Cancer Research UK states there is no reliable evidence that it works. Promoters have been convicted of health fraud, and patients who relied on it instead of treatment have died.
See Water memory, Resonance (as metaphor), Solfeggio frequencies
The resonant frequencies of the apparatus itself — frame, stand, tank, mount — as distinct from those of the plate or fluid under study. Any structure absorbs energy strongly when driven at a frequency matching one of its own modes, so a pattern that appears only there may be telling you about the furniture.
A circular lamp or flash that surrounds the lens so light comes from all around the optical axis, giving even, nearly shadowless illumination for close-up work. On a reflective surface such as water or soap film it produces a ring-shaped reflection, which is why LED ring arrays are used to draw concentric patterns in cymatics footage.
See Macro photography, Specular reflection, RGB additive colour
A shallow glass tray of water lit from above so that ripples cast light-and-dark shadows on a screen below, with waves made by a motor-driven paddle or dipper. It demonstrates reflection, refraction, diffraction and interference directly, and its shadow-casting method is the same optical trick that many water-cymatics rigs use.
See Interference, Wave, Faraday wave
English natural philosopher who, on 8 July 1680, ran a bow along the edge of a flour-covered glass plate and saw nodal patterns emerge, a century before Chladni. His observation went largely unpursued, so the systematic study and the name belong to Chladni, but it is the earliest recorded cymatics experiment.
Most CMOS sensors read out line by line rather than all at once, so the top and bottom of a frame are captured at slightly different moments. Fast motion skews, camera vibration produces wobble, and a strobe flash may light only some rows. A global shutter sensor exposes the whole frame in one instant and avoids this.
See Flicker, Stroboscope, PWM flicker
A common household substitute for sand on a Chladni plate, bright and easy to see against dark metal. Its crystals are coarser than fine sand, so the nodal lines it draws are a little broader. It migrates to the nodal lines within seconds of the plate reaching resonance, and it absorbs moisture, so keep it dry.
See Sand, Tracer particles
How many times per second a signal is measured or reproduced, in hertz. Audio commonly uses 44.1 kHz, the CD rate, or 48 kHz for video and broadcast. The rate must be more than twice the highest frequency present, a requirement that follows from the sampling theorem.
See Nyquist frequency, Digital-to-analogue converter, Temporal aliasing
The standard Chladni plate tracer since the 1780s. Extra-fine, dry sand from a shaker gives the sharpest nodal lines, and commercial kits supply it silica-free or as white sand for contrast on a dark plate. Jenny used quartz sand on a black drum membrane for his tonoscope work.
A bob hung from a V of strings so it swings with different periods in two perpendicular directions; a container of sand at its tip leaves a Lissajous figure on the paper below. Described by Hugh Blackburn in 1844 and earlier by James Dean and Nathaniel Bowditch in 1815, it is the simplest harmonograph.
A waveform that ramps steadily up then drops sharply back, or the reverse. It contains every integer harmonic, even and odd, making it the richest of the standard function-generator shapes and the least selective if you are trying to excite one mode of a plate cleanly.
An optical method that makes invisible variations in refractive index, such as heat, pressure or sound in air, appear as light and dark regions. Developed by August Toepler in 1864, it uses a collimated beam and a knife edge at the focus to block undeviated light. It can image sound fields directly, which shadowgraphs cannot do so sensitively.
See Shadowgraph, Refraction
Real electromagnetic resonances of the cavity between the Earth's surface and the ionosphere, excited by lightning, with a fundamental near 7.83 Hz and higher peaks at 14.1, 20.3, 26.3 and 32.5 Hz. It is an electromagnetic phenomenon, not a sound, and 432 Hz or 'grounding' products that invoke it round 7.83 to 8 to make the arithmetic work.
See 432 Hz, Brainwave bands, Resonance
A clip whose end joins its beginning without any visible jump, so it can repeat indefinitely. Periodic phenomena such as a standing wave lend themselves to it if the cut lands on the same phase of the cycle. On the web the loop attribute of the HTML video element restarts playback automatically.
The simplest way to see refractive disturbances in a transparent medium: a small bright source casts a shadow of the medium onto a screen, and any bending of light shows as brighter and darker patches. Wikipedia describes it as simpler than schlieren. A point light above rippling water gives a shadowgraph of the wave pattern on the floor of the vessel.
The cinema way of stating shutter speed relative to frame rate, from the rotating disc shutter of a film camera. Shutter angle divided by 360 equals exposure time divided by frame interval, so 180 degrees means each frame is exposed for half its duration. It gives the familiar amount of motion blur.
See Shutter speed, Frame rate
How long the sensor is exposed for each frame. Short exposures freeze motion, long ones blur it and gather more light. Standard steps halve or double the time, from around 1/1000 s to 1 s on film cameras. A fast shutter can turn a blurred vibrating surface into a crisp instantaneous snapshot of the wave.
See Shutter angle, Exposure, Flicker
An instrument that produces electrical signals with set amplitude, frequency and wave shape. Function generators typically offer sine, square, triangle and sawtooth outputs; arbitrary waveform generators let you define the shape yourself. In a cymatics rig it is the source feeding the amplifier, and its frequency dial is what you turn to move between modes of a plate or vessel.
The smooth back-and-forth motion of a body pulled towards rest by a force proportional to its displacement, tracing a sine wave in time. A pure tone from a signal generator produces simple harmonic motion in a loudspeaker cone, and each mode of a plate or liquid surface moves this way at small amplitude.
A tone whose waveform is the mathematical sine function: a single frequency with no harmonics, heard as a smooth, characterless whistle. Fourier showed that any repeating waveform can be built from sine waves, which is why the sine is the basic test signal in acoustics and the usual drive for a Chladni plate or water dish.
See Waveform, Fourier transform, Drone
A wave whose shape follows the sine function. It contains a single frequency with no harmonics, which is why it is described as an acoustically pure tone. Sine drive is the standard for cymatics because any pattern that appears can be attributed to one frequency rather than to a mixture of overtones.
A metal or quartz bowl rubbed or struck to produce long, beating drone tones, central to sound baths and a favourite subject for water cymatics because the rim vibration patterns the liquid inside. A 2025 systematic review of fourteen studies found reduced anxiety and depressive symptoms but small samples, weak blinding and low-to-moderate certainty.
See Sound bath, Sound healing, Beats
The effect of recording faster than you play back, historically called overcranking. Shoot at 240 frames per second and play at 30 and the action runs eight times slower. It is how a droplet bounce or a splash crown becomes legible to the eye.
A sheet of water sandwiched between two layers of surfactant molecules, thin enough to show interference colours. As water drains under gravity the film thins, and the colour bands migrate; the thinnest regions look golden, then silver, then black. Its low mass makes it respond visibly to sound.
Light from a physically large source, such as a lamp through a softbox or diffusion sheet, so that shadows have soft edges and reflections on shiny surfaces spread into broad, gentle highlights. On water and film a large soft source gives a smooth reflected sheet in which the ripple pattern reads as gradual shading rather than as harsh glints.
The teaching system that assigns sung syllables — ut or do, re, mi, fa, sol, la — to degrees of the scale. Guido of Arezzo devised it in eleventh-century Italy, taking each syllable from the opening of a line of the hymn "Ut queant laxis". It has nothing to do with the modern "Solfeggio frequencies".
A set of six (later nine) frequencies, 396, 417, 528, 639, 741 and 852 Hz, promoted as ancient healing tones. They were actually derived by Joseph Puleo in the 1970s through numerology on verses in the Book of Numbers and published with Leonard Horowitz in 1999. There is no documentary link to Gregorian chant and no robust evidence that they heal anything.
See 528 Hz, 432 Hz, Sound healing
A 2013 documentary and follow-up by musician Eric Rankin proposing that geometry and frequency form a universal language and that certain harmonics hold keys to creation, drawing on numerology and ancient Sumerian symbolism. It borrows cymatics imagery, but its central claims are speculative and are not supported by acoustics or physics.
See Cymatics
An interactive cymatics installation by Sven Meyer and Kim Pörksen, shown at the Olympus photography playground in Berlin from 26 April to 24 May 2013 and since elsewhere. A plate on a speaker carries a glued bottle cap filled with water; a macro camera above projects the live surface, and visitors can add their own sounds.
Turning data into non-speech sound so it can be heard rather than seen, from the click of a Geiger counter (1908) to audio renderings of seismic or astronomical data. Cymatics is the reverse operation, making sound visible; the two are often paired in exhibitions and sound-art work.
See Spectrogram, Bioacoustics
Faint light emitted by tiny gas bubbles collapsing in a liquid driven by intense sound, first noticed in 1934 and produced as a stable single trapped bubble by Gaitan and Crum around 1990. The collapse briefly reaches temperatures of order 10,000 kelvin. The exact mechanism is still debated, and despite fringe claims it is not a route to fusion.
A group session in which people lie still while a practitioner plays sustained tones on singing bowls, gongs and similar instruments. It is a form of sound healing, marketed for stress and sleep. Reviews of singing-bowl studies find reduced self-reported anxiety and some heart-rate changes but rate the evidence low to moderate because of small, poorly controlled trials.
See Sound healing, Singing bowl, Drone
An unregulated alternative practice using singing bowls, gongs, tuning forks, chanting and recorded 'frequencies' for relaxation and claimed cures. It is distinct from music therapy, a regulated clinical profession. Sessions can be relaxing and small studies report lower anxiety, but there is no good evidence for the specific frequency-to-ailment claims that often accompany it.
A microphone and meter reporting sound pressure level in decibels, referenced to 20 micropascals. A-weighting, mandated for hearing-protection measurement in most countries, discounts low and high frequencies to match human sensitivity at quiet levels. Class 1 instruments have tighter tolerances and wider frequency range than cheaper Class 2 units.
See Spectrum analyser, Calibration, Flash rate safety limits
The small rise and fall in air pressure that a sound wave adds to the steady atmospheric pressure, measured in pascals; sound pressure level in decibels is quoted relative to 20 micropascals, roughly the threshold of hearing. When sound drives a plate or liquid through the air, sound pressure is the force actually doing the work.
See Longitudinal wave, Acoustic radiation pressure, Speed of sound
The strength of a sound expressed in decibels relative to 20 micropascals, roughly the quietest 1 kHz tone a young ear can detect (0 dB). Normal conversation sits around 40 to 60 dB, a vacuum cleaner near 85 dB, and pain begins around 120 to 130 dB. Cymatics rigs driven hard enough to move water or sand often sit well into the hazardous range.
See Decibel, Hearing safety, A-weighting
The moving part of a loudspeaker: a linear motor coupled to a diaphragm that moves air. Woofers cover low frequencies, tweeters the highest. In cymatics a driver is often used without its usual job of making audible sound, instead coupling its motion directly into a plate, membrane or dish.
See Voice coil, Subwoofer, Exciter
The simplest liquid cymatics rig: a shallow dish of water or another liquid rests on a plate glued to a loudspeaker cone, or liquid sits straight on a waterproofed cone, and a tone makes the surface ripple into standing patterns. Sonic Water used a bottle cap of water on a plate on a speaker; a light and a camera above complete it.
A picture of a sound with time along the bottom, frequency up the side and brightness or colour for level, built from a run of short Fourier transforms. Spectrograms show sweeps, harmonics and bird calls at a glance. They are one of the oldest ways of making sound visible, and a useful companion to a cymatic image because they show what was actually played.
A description of a signal by how much energy sits at each frequency rather than by how it changes in time. A spectrum analyser draws it with frequency along one axis and level up the other, revealing the fundamental, harmonics and resonant peaks. It is the tool for checking that the tone you think you are sending to a plate is the one arriving.
An instrument that plots amplitude against frequency rather than against time, showing which frequencies are present and how strong each is. Audio versions are usually FFT-based software. Use one to confirm a drive tone is a clean single frequency, and to see the harmonics that clipping or a rattling mount adds.
Mirror-like reflection from a smooth surface, where each ray leaves at the same angle it arrived. Still water, glass and soap film reflect specularly, so the camera sees a sharp image of the lamp rather than the surface itself; a standing wave on water is seen mainly by how it distorts that reflected image.
How fast a sound wave travels through a medium: about 343 metres per second in air at 20 °C and about 1,480 metres per second in fresh water, depending on temperature and on the medium's stiffness and density. It fixes the wavelength for a given frequency and so the spacing of nodes in Kundt's tube and resonant air columns.
Sound patterning on a curved, closed surface such as a bubble, a balloon or a droplet rather than a flat plate, so the modes wrap around in three dimensions. Reports include dyed balloons showing symmetric nodal traceries and levitated droplets taking polyhedral shapes; it remains a small, mostly artist-led corner of the field.
A waveform that alternates abruptly between fixed high and low values, spending equal time at each when the duty cycle is 50 per cent. An ideal square wave contains only odd-integer harmonics of the fundamental, so driving a plate with it excites several modes at once and gives a busier figure than a sine.
See Duty cycle, Sine wave, Clipping
A wave pattern that stays in place instead of travelling, formed when waves moving in opposite directions (typically a wave and its reflection from an edge) overlap. Some points never move (nodes) while others swing the furthest (antinodes). Chladni figures, the powder piles in Kundt's tube and Faraday patterns are all standing waves.
How many flashes per second a strobe emits, in hertz. Set equal to the drive frequency, a vibrating surface appears frozen; set a fraction of a hertz away, it drifts through its cycle in apparent slow motion. That small offset is the most useful single control on a cymatics lighting rig.
A device producing regular short flashes of light. Xenon flashtube units give very brief, very bright flashes; LED strobes are dimmer but reach full brightness in under a microsecond and are far easier to control precisely. Flashing light near a vibrating surface is the standard way of making cymatic motion visible.
A lamp that flashes at a set rate so that a repeating motion appears to stand still or crawl slowly when the flash rate is at or near the motion's frequency. The idea goes back to Plateau and Stampfer in the 1830s; Harold Edgerton made the electronic flash version. Phase-locking a strobe to the driving tone lets a camera see a wave's shape.
The apparent change in a cyclic motion when it is sampled by flashes of light or camera frames instead of watched continuously. Match the flash rate to the vibration frequency and the motion appears to stop; offset it slightly and the motion appears to crawl forwards or backwards.
Colour produced by microscopic structure fine enough to interfere with light, rather than by pigment. Thin films, diffraction gratings and photonic crystals all do it; peacock feathers, butterfly wings, CDs and soap bubbles are examples. Hooke described it in 1665 and Newton explained it in 1704. Its colours shift with viewing angle and are hard to reproduce by dye.
See Iridescence, Thin-film interference, Diffraction grating
A frequency at a whole-number fraction of the driving frequency: half, a third and so on. Faraday waves are the classic example, since a liquid surface shaken at one frequency typically responds at half that frequency, so a 60 Hz drive gives a 30 Hz surface pattern. A strobe locked to the drive must allow for this.
The odd fact, first noted by Faraday, that the standing waves on a vertically shaken liquid normally oscillate at half the frequency of the shaking. It is a parametric resonance rather than a simple forced one, and it matters when phasing a strobe against the drive signal: the pattern repeats every two drive cycles.
See Faraday waves, Crispations
A loudspeaker built only for low frequencies, roughly 20–200 Hz in consumer use and below about 100 Hz in live sound. Its long-throw driver and large cone make it a common choice for water-dish and membrane cymatics, where useful patterns often sit below the range a small driver can move at all.
The rule that in a linear system the effect of several waves acting together is simply the sum of their separate effects. It is why two ripples cross a ripple tank without disturbing each other, and why a complex sound can be treated as a stack of pure tones. Large-amplitude cymatics often breaks the rule.
See Interference, Nonlinearity
The tendency of a liquid surface to behave like a stretched elastic skin, measured in newtons per metre. It sets the size and speed of capillary waves, holds a bubble film together and shapes the meniscus at a vessel wall. Surfactants such as washing-up liquid cut water's surface tension by a factor of three or more, changing the patterns markedly.
When a symmetric system settles into a less symmetric state: a round dish of liquid, shaken uniformly, chooses a square or hexagonal lattice with a particular orientation. The equations do not prefer any direction; tiny imperfections or noise decide. It explains why nominally identical runs can give differently oriented or mirrored patterns.
A voice-coil device that drives a small internal weight instead of a diaphragm, so it shakes whatever it is bolted to rather than making sound. Typically fed 25–50 watts of low-frequency signal. Useful for vibrating a table, tank or rig frame with far less airborne noise than a subwoofer would add.
Aliasing in time: when a repeating motion is sampled too slowly, it reappears as a different, slower or reversed motion that was never there. It is the same folding that happens above the Nyquist frequency in audio, and it is exactly what a strobe or a camera does to a vibrating surface.
The physics behind bubble cymatics. When a soap film across an open tube is driven by sound at the right frequency and level, counter-rotating vortex pairs form and mix regions of different thickness; light reflecting from the film's front and back surfaces interferes, so those thickness changes appear as moving bands of colour.
Light reflecting from the top and bottom surfaces of a very thin transparent layer overlaps and interferes, reinforcing some wavelengths and cancelling others. Which colours survive depends on the film's thickness, so a bubble or soap film that is thinning shows shifting bands of colour and finally turns almost black.
The quality that tells a guitar from a piano on the same note at the same loudness. It comes from the spectrum of partials and from the envelope (attack, decay, sustain, release). Because a rich timbre drives a medium at many frequencies at once, complex sounds usually give muddier cymatic figures than a single sine.
See Harmonic series, Spectrum, Waveform
Capturing frames much more slowly than they will be played back, so slow processes appear fast. Shoot one frame per second, play at 30, and an hour becomes two minutes. It is the mirror image of overcranking, and suits drying, crystallising or evaporating subjects.
See Slow motion, Frame rate
Capturing frames at a much slower rate than they will be played back, so slow changes appear fast; one frame per second shown at 30 frames per second runs thirty times faster. Useful for showing a soap film draining or a sand pattern forming over minutes, and the opposite of slow-motion recording.
Hearing ringing, hissing or buzzing with no outside source, affecting roughly 10 to 15 per cent of people and seriously troubling one to two per cent. Prolonged loud noise is a leading cause. Cognitive behavioural therapy has the best evidence; sound maskers and 'notched' music are poorly supported, and no drug has been shown to cure it.
Software, usually a phone app or a web page, that plays a chosen frequency through the device's own output. Handy for a first look at a plate, but limited: phone speakers roll off badly at the low frequencies most water cymatics needs, and turning the volume up to compensate risks both your hearing and the hardware.
A JavaScript framework its authors describe as "a Web Audio framework for creating interactive music in the browser". Built on native Web Audio nodes, it adds a global transport for scheduling and synchronisation, prebuilt synths and effects, and building blocks for control signals — convenient for driving a rig from a browser page.
A device Hans Jenny described in Kymatik for driving a membrane acoustically with no electronics: you sing or speak through a tube and the sound vibrates a diaphragm carrying sand, powder or liquid. Jenny used quartz sand on a 60 cm black drum membrane; low tones gave simple figures and higher tones more complex ones.
When light inside water or glass reaches the surface at a steep enough angle it cannot escape and is reflected back entirely. Seen from below, a water surface is a mirror outside a cone called Snell's window. It matters when vessels are lit or filmed from underneath, because much of the light never leaves the water.
A node-based visual programming environment for real-time interactive multimedia, made by the Toronto company Derivative. Projects are assembled from operators — nodes handling images, 3D geometry, channel data and so on. It is a common choice for driving projection, lighting and DMX from live audio in an installation.
Whatever is sprinkled or poured on a vibrating surface to make the motion visible: sand, salt, flour, lycopodium spores, a thin paste or a liquid. Heavier grains bounce to the nodal lines; the lightest powders can drift the other way. The kit rule is to use only as much as needed, since extra mass damps the higher modes.
See Sand, Lycopodium powder, Salt
A wave in which the medium moves at right angles to the direction of travel, as on a plucked string or a rippled water surface. The flexing of a Chladni plate and the up-and-down motion of Faraday waves are transverse, even when they are excited by longitudinal sound in the air or by a shaker.
See Longitudinal wave, Plate
A periodic waveform that ramps linearly up and then linearly down. Like a square wave it contains only odd harmonics, but their amplitudes fall off as the inverse square of the harmonic number, so it is far less bright. In harmonic content it sits between sine and square.
A signal or condition that starts something at a defined moment. On an oscilloscope the trigger begins each sweep when the input crosses a set voltage in a set direction, which is what stops the trace sliding across the screen. In a rig the same idea fires a flash or a camera at a chosen phase.
A two-pronged steel fork, invented by John Shore in 1711, whose first overtone lies so far above the fundamental that after a moment it rings as a near-pure sine tone. Used to tune instruments, in hearing tests, and in unregulated 'sound healing' practices. A fork's pitch drifts flat by roughly 86 parts per million per degree Celsius as it warms.
A transmitter or receiver working above 20 kHz, the top of human hearing, usually piezoelectric. Arrays of them make acoustic levitation rigs work, holding droplets and beads at the nodes of a standing wave. The same principle drives ultrasonic atomisers, which throw a fine mist off a liquid surface.
Sound above 20 kHz, beyond human hearing. It is used for medical imaging, cleaning by cavitation, sonar, and acoustic levitation, typically with 40 kHz piezo transducers. Diagnostic ultrasound has no known patient risk at clinical intensities, but occupational exposure above 120 dB can damage hearing and very high levels cause heating.
The repeated movement of something back and forth about a rest position, such as a loudspeaker cone, a metal plate or the surface of a liquid. Every cymatic pattern begins as vibration: a driver shakes a plate, membrane or vessel and the medium responds by moving in a repeating cycle.
Preventing vibration passing from one part of a system to another, using springs, elastomer pads, air mounts or wire rope isolators. A passive isolator behaves as a mechanical low-pass filter with its own natural frequency, often only a few hertz, below which it does not help at all.
Lying on a bed, chair or mat with built-in speakers that pass low sine tones, usually 30 to 120 Hz, into the body. Developed by Olav Skille in Norway in the 1980s. The sensation is real and often relaxing, and regulators treat the devices as therapeutic vibrators; the evidence for specific medical benefits is thin and critics call much of the marketing pseudoscience.
See Vibrotactile perception, Body resonance, 40 Hz gamma stimulation
Vibration perceived through the skin and body rather than the ears. Fast-acting mechanoreceptors respond to vibration, which is why tactile transducers, bass shakers and a driven plate can be felt as well as heard. Evelyn Glennie, profoundly deaf since childhood, performs barefoot in order to sense music through her body.
Feeling vibration through the skin and body. Pacinian corpuscles, rapidly adapting receptors in the skin, respond best around 250 Hz, which is why bass and sub-bass are felt as much as heard at a loud gig. Vibroacoustic devices and 'felt sound' installations work on this sense rather than on hearing.
Software that compresses video for storage and streaming by predicting each frame from its neighbours and discarding detail the eye is unlikely to miss. H.264, standardised in 2003, plays in every major browser and remains the safe default for web delivery. Newer codecs shrink files further but are not supported everywhere.
See H.265, AV1, Compression artefacts
A liquid's resistance to flowing and being sheared, given as dynamic viscosity in pascal-seconds or kinematic viscosity (dynamic viscosity divided by density) in square metres per second. Viscosity damps surface waves: thin liquids like water give sharp, lively Faraday patterns, while glycerine or oils give broader, slower ones and favour stripes over squares and hexagons.
A coil of wire that sits in a narrow gap containing a concentrated magnetic field from a permanent magnet. Current through the coil forces it to move axially, and the cone, panel or plate attached to it moves with it. Coils are made light and are therefore delicate, and they have to shed the heat the drive current puts into them.
The illusion in which a spoked wheel on film appears stationary or turning backwards. It happens because the camera samples the motion at discrete moments; if the wheel advances by nearly a whole spoke between frames, the brain reads it as a small backwards step. The same aliasing makes vibrating water look frozen under strobes.
See Aliasing, Stroboscope, Frame rate
How deep the liquid sits in a vibrated dish. Depth is one of the variables, alongside viscosity, surface tension and container shape, that set the threshold and wavelength of Faraday waves, so a few millimetres more or less changes which patterns appear and how easily. Shallow layers are usual for photography.
See Faraday waves, Meniscus, Viscosity
The claim that water retains an imprint of words, thoughts or music. Masaru Emoto (1943-2014) photographed ice crystals he described as beautiful after positive stimuli and ugly after negative ones. The work lacked controls and blinding, and he did not take up James Randi's million-dollar challenge in 2003.
Alexander Lauterwasser's term for photographs of water surfaces set in motion by sound, from pure sine tones to music by Beethoven and Stockhausen and overtone chanting. Wasser Klang Bilder appeared in German in 2002 and in English as Water Sound Images, a 176-page book with 240 colour photographs, in 2006 to 2007.
A disturbance that travels through a medium or space, carrying energy without carrying the material itself along with it. Ripples on water, sound in air and flexing in a metal plate are all waves; cymatics makes them visible by giving the medium something to show, such as sand, powder or reflected light.
The basic equation of wave motion, which in words says that how fast a point accelerates is proportional to how sharply the medium is curved around it, with the wave speed squared as the constant of proportionality. Solving it for a given shape and edge conditions yields the modes and frequencies that cymatic patterns display.
The shape of a signal plotted against time. A sine wave contains one frequency; square, triangle and sawtooth waves are built from a fundamental plus harmonics in fixed proportions, so they sound brighter and drive a plate or liquid at several frequencies at once. For clean cymatic figures most people start with a sine.
See Sine tone, Harmonic series, Timbre
The distance between one crest of a wave and the next, or between any two neighbouring points at the same stage of the cycle. Wavelength equals wave speed divided by frequency, so on a given medium higher frequencies mean shorter wavelengths and finer patterns. Nodes in a standing wave are half a wavelength apart.
The audio system built into web browsers. You create an AudioContext and then wire together audio nodes — sources, filters, gain stages — into a routing graph ending at a destination. Its OscillatorNode produces sine, square, sawtooth, triangle or custom waveforms, which makes an ordinary web page a workable tone source for a rig.
The camera adjustment that makes neutral greys and whites appear neutral under a given light, compensating for the colour temperature of the source. If left on automatic while coloured LEDs cycle, the camera will keep shifting the overall tint; locking white balance keeps the colours of an RGB rig consistent from frame to frame.
A random signal with equal power at every frequency, heard as a flat hiss. Engineers use it to measure impulse responses, synthesists to build snare and cymbal sounds, and sleep devices to mask other noise. Fed to a plate or liquid it excites every resonance at once, so it produces movement but rarely a clean figure.
Vibration transmitted into the whole body through a seat or the feet, mainly an occupational hazard for drivers and linked to back pain. In Britain the Control of Vibration at Work Regulations 2005 set a daily exposure action value of 0.5 m/s² A(8) and a limit value of 1.15 m/s² A(8).
An RGB LED with its driver chip built into the same package, controlled over a single data wire. Pixels chain output-to-input so one microcontroller pin can run a long string, each element individually addressable. Adafruit markets them as NeoPixels; related parts include the WS2811 and SK6812. They run from 5 volts.