I’m exploring how sound can make patterns in water.
Cymatics makes vibrations visible. Repeated pushes create waves that can reinforce each other and form patterns.
Think of pushing a swing at just the right moment: each push adds to the motion. That’s resonance. Water can respond to a repeating push in a similar way. Some places move a lot; others stay almost still. The quiet lines are easier to see in Nodal pattern.
Try this: Tap a note, then move the pitch slider. Drag to rotate the basin, or use Top down to look straight down. Choose the Stir drag mode to disturb the water. The slider and notes control the same tone; Stop sound ends it.
This is simulated water. The listening tone is shifted above the water’s driving frequency so you can hear it; your speakers are not physically making these patterns.
Drag to rotate · 8 cm basin · motion at 1/16 speed. Water drive: 16.35 Hz · listening tone: 261.63 Hz.
This basin receives a repeating local push. Many water cymatics experiments shake the whole container vertically. Strong enough shaking produces Faraday waves, often at half the driving frequency. Depth, container shape, and shaking strength all matter. This app does not simulate that instability.
Watch the reflected lights bend and the floor lines shift through the water. Bright moving patches on the floor are focused light, called caustics. Higher water frequencies generally make finer ripples; the animation runs at 1/16 speed so you can follow them.
Experiments: photographs of driven water surfaces ↗ · How water focuses light ↗
A basin supports different standing-wave modes. Changing frequency changes which modes respond most strongly. Pale lines in Nodal pattern mark low surface amplitude.
Choose Stir under “Drag to” to push a 2D fluid flow that carries the wave envelope. The continuous driver brings the resonant pattern back as the flow settles. Set coupling to zero to compare.
440 Hz is the standard tuning reference for A4. Try 432 Hz to lower the whole keyboard slightly. With equal temperament, middle C is 261.63 Hz at your chosen tuning. C has no single frequency without an octave and tuning reference.
Each semitone multiplies frequency by 2^(1/12); each octave doubles it. This keyboard uses equal temperament and fixed-do note names. The basin’s size, depth, damping, and driving frequency determine its response—note names do not add a separate physical effect.
ω² = (gk + σk³/ρ) tanh(kh)
Natural frequencies use linear gravity–capillary dispersion for water, with a rigid square boundary and approximate damping. The strongest 18 modes from indices 0–24 are superposed. The driver is at (0.37, 0.43) of the basin width.
A separate 2D incompressible Navier–Stokes solver advects the complex wave envelope, which relaxes toward the driven response. This is one-way reduced coupling, not a full 3D free-surface or acoustic simulation. The waves do not push the flow back. Display contrast is normalized, so brightness is not a physical displacement measurement. Animation runs at 1/16 of the driving frequency; displayed height is exaggerated and limited by the basin depth.
Surface slopes bend reflected studio lights and refract the view of the basin using water’s refractive index (1.333). Light concentration on the floor is an approximation; it does not trace every light ray or reproduce splashes and droplets. The listening tone is 4 octaves above the water drive to make it audible; both follow the same pitch control. This models directly driven water-surface modes. It does not model gas acoustics, cavitation, or the parametric instability of a vertically shaken Faraday experiment. The optional tone is a listening aid, not a claim that your speakers would recreate the displayed pattern.