Mean Free Path Lab
Explore the average distance a gas particle travels between collisions.
The Concept
Gas particles are in constant, random motion, frequently colliding with one another. The Mean Free Path is the average distance a particle travels between these collisions. It's a key concept in understanding gas properties like viscosity and diffusion.
What to look for
- The yellow particle is our tracer. It leaves a trail showing its current path.
- When it collides with another particle, the trail resets.
- Observe how the Mean Free Path changes as the gas becomes more or less crowded.
Experiment Controls
Analysis
Adjust the number of particles to see how it affects the average distance the yellow particle can travel before hitting another.
Live Data
Last Path Length: 0 pm
Mean Free Path (λ): 0 pm
(pm = picometers, 10⁻¹² m)
This box is packed far more densely than real air so that collisions are easy to see. In real air at room temperature, λ ≈ 68 nm (68,000 pm), about 200 times the size of a molecule. Theory: λ = kBT / (√2·π·d²·P).