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Brownian motion
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Single grain of dust
Two grains of dust
Increase the temperature
Looking at the motion
Comparing particles
Investigating Brownian Motion

by David Sang
Paul Berry

Brownian motion (or Brownian movement) can be defined as "the random movement of microscopic particles suspended in a fluid."  

In this series of pages, we will be building up the concept of Brownian motion using a series of simulations based on dust particles suspended in still air.

Learning outcomes

After completing this section, you should be able to:

describe the nature of Brownian motion in terms of dust-air interactions;
explain how the motion of a dust grain is affected by (a) its mass and (b) temperature; and
describe how the displacement of a particle from its initial position changes with elapsed time.

External links image

Brownian movement in Clarkia pollen: a reprise of the first observations - Background to Robert Brown and his observations.

Materials Teaching Educational Resources
1999 MATTER Project, The University of Liverpool

ESF flagSupported by the European Social Fund under
the Objective One programme for Merseyside