Looking to the Blue Sky with Colored Patterns

Abstract: This work presents a simple alternative technique to observe the polarization of the skylight on Earth. Using a birefringent material and a polarizer to look at the polarized light from the blue sky, it is possible to see a colored pattern that is associated to the birefringence of the material and the polarized light. Three different ways to polarize the light are also discussed in the context of the proposed experiment. Keywords: Blue sky, Rayleigh scattering, birefringence, polarization, education.