PRESSURE · PARTICLES · POSSIBILITIES

Gas Lab.

FREE LAB

Choose what to change. Hold something constant. Find a relationship.

Investigation Your experiment. Your question.

TEMPERATURE GAS SUPPLY

Drag the piston when volume is editable. Left and right arrows change volume by five percent; hold Shift for one percent. Use the controls for exact values. Space runs or pauses the representative particles.

YOUR IDEAL GAS EXPERIMENTA movable piston. A world of relationships.

Particles paused

Drag the piston or use the gas controls.

SET UP YOUR EXPERIMENT

Calculate automatically

Lock any input to hold it constant. The calculated quantity follows the ideal gas law.

Molecules & gas type

Ideal gas · molar mass preset

All gases use the ideal-gas approximation. Molecular size and chemistry are not simulated.

Velocity arrows Track a molecule Grid

Representative particles · motion slowed

EQUILIBRIUM READINGSIdeal gasp calculated · inputs unlocked

Pressureabsolute pressure

Volume1 L = 10⁻³ m³

Temperature

Amount

PUT YOUR PREDICTION TO THE TEST

Record changes

Dataset 0 / 200 readings

Horizontal axis Vertical axis Straight-line fit Include zero

A relationship starts with a reading.

Change one quantity. Take a few readings. See what the graph reveals.

Recorded equilibrium model values. Choose any pair of quantities to investigate.

Equilibrium model readings, not noisy experimental measurements. CSV contains all current and kept datasets in SI units.

SPEEDS ARE DISTRIBUTED

One temperature. Many speeds.

Sample Maxwell–Boltzmann

Three velocity components are sampled; the chamber shows their 2D projection. The histogram uses full 3D speeds.

Follow a wall collision.Switch on “Track a molecule”, then Run. Its latest visible-wall collision appears here.

These expressions describe the same equilibrium state. Their agreement is algebraic; pressure is calculated from the ideal gas law, not measured from the animated collisions.

TRY THIS

Keep T and n fixed. Halve V. What do you predict will happen to p?

Made for curious minds. PhysicsUK

Ideal equilibrium states · absolute pressure · translational energy

A LITTLE HELP GETTING STARTED

Change something.
Discover a relationship.

Free Lab: choose which quantity to calculate. Edit the other quantities, and lock any you want to hold constant. Changing the calculated quantity preserves your gas state.
Make it an experiment: drag the piston, warm or cool the gas, or add molecules. Controls show which quantities are held constant. Use numeric fields for exact values.
Take readings: each click records a complete gas state. “Record changes” takes a reading after each completed edit. Choose graph axes, keep up to three datasets, or export CSV.
Look closer: Kinetic Theory shares your current gas state. Track a molecule or compare the speed histogram with the Maxwell–Boltzmann curve. Challenges give you a target to achieve.

Units: pressure is absolute, temperature is in kelvin, and volume controls use litres. Equation substitutions and CSV use SI units. 1 L = 10⁻³ m³. Celsius is available as a graph axis.

Model: every control change selects a new ideal-gas equilibrium state. Prescribed constant temperature represents an ideal thermal reservoir; constant pressure represents a quasistatic loaded piston. This lab does not model transient piston dynamics, adiabatic processes or real-gas effects. “Warm” changes temperature by 25 K; it does not specify an amount of heat.

Moving the piston: expansion opens empty space; particles keep their positions and move into it when running. Compression pushes only particles reached by the boundary. Fit adjusts the view scale when you need more room on screen.

Particles: dots are a representative, non-interacting sample with three velocity components and elastic wall reflections. Positions and playback time are illustrative. Pressure readouts come from pV = nRT. The sample is normalised to the displayed translational temperature. The number represented by a dot can change. Molecular rotation and vibration are excluded from the energy readouts.

Keyboard: focus the chamber and use left/right arrows to change volume; Shift makes a smaller change. Space runs or pauses particles. Exact controls and variable locks work with the keyboard. Reduced-motion settings start the particles paused; you can explicitly Run or Step.

Files: save includes the gas state, locks and current/kept readings. Open restores it in Free Lab. Your latest experiment is recovered locally when browser storage is available.