Polarization

Simulating Atmospheric Scattering

Atmospheric scattering may be simulated by adding a few drops of milk to a container of water. This simulation works because the solid particles in milk are much smaller than the wavelength of visible light. So if you can't go outside, you may wish to try performing the following demonstration of scattering.

First fill a transparent container with water. Shine a flashlight beam through the water and observe the scattered beam from the side of the container. Also observe the transmitted beam by projecting it onto a piece of paper. Describe the scattered and transmitted light.

Now add a little milk to the water, a drop or two at a time. Carefully note the color of the mixture as the milk is stirred into the water. What color is the scattered light now? Note also the color of the transmitted light that is projected on the paper. What color do you observe on the paper? Continue adding milk in small amounts and notice changes in the scattered and transmitted light. Describe these changes. View the blue light scattered by the milk particles through a Polaroid filter. What do you observe as you slowly rotate the filter? Can you explain your observation? Also look at the top of the water through the rotating filter. What do you observe?

Finally, use a polarizing filter to examine the transmitted beam. Is this light polarized? Additionally, place the polarizing filter between the flashlight and the milky water. Look from the side and notice what happens when you rotate the polarizer. Also notice what happens to the transmitted red "sunset."