This simulator shows a piston vibrating at one end of a transparent acoustic channel, sending a plane pressure wave down a lattice of air particles. Change source frequency, RMS pressure and air temperature, slide a pressure probe along the channel, and see that the wave travels while each particle only oscillates about its resting position.
• A 3D cutaway of an acoustic channel with a driven piston, an air particle lattice whose displacement is enlarged 2000 times so it is visible, a teal and violet pressure trace separating compression from rarefaction, and a movable pressure probe. • Controls for source frequency, RMS pressure, air temperature and probe distance, with a toggle for wave and motion markers. • Six live readouts: sound speed, wavelength, sound pressure level in dB re 20 µPa, mean intensity, probe pressure and peak particle displacement. • A Curves & measurements tab with the model equations, an Experiments tab with two guided presets and a verification bench with an event log, and a Learn & assess tab with lessons and a quiz.
Sound is a longitudinal pressure wave. The piston pushes and pulls on the air, and the disturbance moves down the channel at the speed of sound, c = 331.3 + 0.606 T with T in °C. Each particle only oscillates back and forth along the direction of travel. In the model, particle displacement is a quarter cycle out of phase with pressure, so a particle is at its resting position when the local pressure peak passes.
Wavelength is λ = c/f, so doubling the frequency at constant temperature halves the spacing between compressions, and warmer air raises c and stretches the wavelength at a fixed frequency.
Mean intensity follows I = p²rms/(ρc) and level follows Lp = 20 log10(prms/20 µPa), so doubling RMS pressure adds about 6 dB. The model is a plane traveling wave with fixed density 1.2 kg/m³, no reflections and no attenuation. One animation second stands for 0.01 acoustic seconds, and there is no audio output. Use it to build intuition for wavelength, pressure and displacement, not to predict the sound field of a real space.
No. Each particle oscillates around a fixed resting position along the direction of propagation. The disturbance and its energy move down the channel at the speed of sound, but the air itself does not stream along with it.
Wavelength equals sound speed divided by frequency, λ = c/f. At constant temperature, doubling the frequency halves the wavelength, which the Double frequency experiment demonstrates by comparing 160 Hz with the 80 Hz default.
Sound speed rises with temperature, roughly c = 331.3 + 0.606 T in °C. At a fixed frequency a higher speed means a longer wavelength, as the Warmer air experiment shows at 40 °C.
Sound pressure level uses 20 log10 of the pressure ratio, so doubling RMS pressure raises the level by about 6 dB. The simulator shows this directly in its live level readout.