FPS: 0
About this simulation
Gas pressure is the combined push of countless molecules bouncing off the walls. Each bounce gives the wall a tiny kick; the simulation adds up the kicks every second and divides by the length of wall to get the pressure.
What you're seeing
- Dots: gas particles (each stands for about 2×1020 molecules), coloured by speed from blue (slow) to orange (fast).
- White flicks: single wall hits. Orange arrows: the average push on each part of the wall. Around the balloon, blue arrows show the outside air pushing back.
- Gauge: the measured pressure. Tap or click it for more readouts and a speed key.
The key idea
More particles make more hits. Hotter particles move faster, so they hit more often and harder. In a smaller volume they reach the walls sooner. Together this gives the ideal gas law, PV = NkT.
Things to try
- Balloon: heat it or add particles and it grows (Charles's law).
- Rigid box: double the temperature in kelvin and the pressure doubles (Gay-Lussac's law).
- Syringe: drag the plunger to halve the volume and the pressure doubles (Boyle's law). With insulated walls, a quick push heats the gas, like a bike pump.
- Piston: the weights fix the pressure, so heating the gas lifts the piston.
- Gas type: light helium and heavy xenon give the same pressure (Avogadro's law).
How to use it
Settings , fullscreen , graphs and restart are under the simulation. Drag the plunger with a mouse or a finger. The model is 2D, so its "volume" is an area, scaled to read in litres.