Class practical: Marbles in a tray illustrate the meaning of 'mean-free-path'.
Practical Activity 14-16
Demonstration: A difficult exercise, photographing marbles to show the differences in their path lengths between collisions.
Class practical: Finding displacement after ‘random walk’ using triangular-grid graph paper.
Class practical: Finding displacement after ‘random walk’ using squared paper.
√N steps gives the average mean free path for a bromine molecule in its wandering amongst air molecules. That would be similar...
Teaching Guidance 14-16
It is interesting for students to see how far physicists can push ‘back of the envelope’ calculations. Diffusing bromine into...
This proof of R = s√N describes an algebraic approach to the random walk problem, sometimes known as the drunkard’s walk: If...
Once students understand the thinking behind estimates of mean free path, s , they can estimate the time for air molecules to...
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