Mean free path and brownian motion
A 2D gas of hard discs: follow a tagged molecule's zig-zag path, count collisions and measure the mean free path; compare with λ = 1/(√2 n d). Add a heavy pollen grain to see Brownian motion ⟨r²⟩ ∝ t.
About this experiment
| Subject | Physics |
|---|---|
| Class | 11 |
| Chapter | 12. Kinetic Theory |
| NCERT section | 12.7 |
| Level | Advanced (JEE / Olympiad) |
| Time | about 12 minutes |
| Access | Included in a PractiSci plan |
What you do in the lab
Change the controls and watch the physics behave in real time in 3D. Live readouts and graphs show the numbers behind it, and the Learn tab has the theory, procedure, observations and viva questions. Works on a phone or a laptop, in English and Hindi.
Topics: mean free path · collisions · Brownian motion · random walk · diffusion