Molecular Speed Distribution
Pick a real gas and sweep its temperature, and watch the curve of how many molecules move at each speed shift, broaden, and flatten — track the shaded fraction moving faster than a chosen speed threshold as the temperature climbs.
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What you can adjust
- Gas
- 0 – 4
- Starting temperature
- 100 – 1500 K
- Ending temperature
- 100 – 1500 K
- Speed threshold
- 0 – 4000 m/s
A heavier gas's molecules move slower on average at the same temperature — its curve peaks further left.
The temperature the curve starts at (300K is roughly room temperature).
The temperature the curve sweeps to over the animation. Higher than the starting temperature flattens and broadens the curve and shifts its peak right; lower does the opposite.
A minimum speed marked on the curve — watch the shaded fraction of molecules faster than this grow as the temperature rises.
About this simulation
What it shows
A curve showing how many molecules of a chosen gas move at each speed. As the temperature sweeps from the start to the end value, the curve shifts, broadens and flattens, and the shaded part shows the fraction above a speed threshold.
The key idea
Molecules in a gas move at a wide spread of speeds. Raising the temperature moves the peak to higher speed and lets more molecules past any given speed, while heavier molecules are slower at the same temperature.
Try this
Compare Helium (He) with Carbon dioxide (CO2) in the Gas control at the same temperatures: helium's peak sits at about 3.3 times the speed.
The curve is the ideal-gas Maxwell-Boltzmann distribution, which treats molecules as tiny particles that do not attract each other.