Uncovering the Colored Light Beam: Exploring Polarising Light Waves

[physicsguy]

Heres a quick question: while conducting an experiment to demonstrate the effect of polarising light waves, i noticed a strange effect. The lecturer used milk and water mixed in a container with a light shining through, allowing the light beam to show. When we looked at the beam from the side, through a polarised lense, the light beam appeared to be coloured, like the surface of oil. I guess this is something to do with defraction, but when i asked the lecturer he did not know how it happened. Can someone explain how this happens.

 

[Astronuc]

Milk is a colloidal suspension of tiny globules of butterfat. One seems to be describing diffraction by the milk particles, or the Tyndall Effect.

https://chem.libretexts.org/Bookshe...Solutions_and_Mixtures/Colloid/Tyndall_Effect

 

[tech99]

When the particles are much smaller than the wavelength, we have Rayleigh Scattering. In this case, the energy of the scattered waves is strongly dependent on the particle size, hence the colour. In the direction at right angles to the incoming rays, the light should be blue and polarised, like the sky.