School of Physics Lecture Demonstration Manual

Og-4 Polarisation by Scattering

Published: Wednesday 15 March 2006 - Updated: Monday 28 March 2011


To demonstrate that scattered light is polarised. When the direction of observation is normal to the primary beam, the light is completely linearly polarized.



Click on pictures to enlarge.

Polarisation By Scattering Diagram


A large fish tank is filled with water; if required a few drops of milk may be added to increase the scattering. A slide projector is used to illuminate the solution. The solution appears bluish white in scattered light and yellowish in direct light indicating that Rayleigh scattering predominates. A large sheet of polaroid is used to investigate the polarization of the scattered light.

Safety notes

Electrical safety 

Sharps safety 


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