Brownian Motion


Brownian motion is the random and irregular motion of gas and liquid molecules. Brownian motion provides clear evidence for the kinetic molecular model of matter in that matter is comprised of tiny particles that are in continuous random motion, with a range of speeds n all directions and kinetic energies.

In the simulation above, it is seen that the particles are seen moving about in a random manner.

Why does the particles move in a random manner?

  • The observed irregular motion of the particles is due to the bombardment of air molecules. The air molecules are too small to be seen. The particles are continually bombarded unevely on different sides by air molecules. This results in the irregular movement of the smoke particles.
  • The random motion of the particles demonstrates that air molecules move randomly in all directions with a range of speeds and kinetic energies.

As temperature increase, the brownian motion of the particles is more frantic. They will move about more vigorously.


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