Science Buddies: "Ask an Expert"

I was wondering why permittivity has an effect on refractive index. Also, what would the key determinant of refractive index be? Mass density doesn't seem to have a consistent effect, as oil, which is less dense than water, has a higher refractive index. I assume the molecular properties of each medium would have the largest effect, but I am unsure as to what specifically would determine the speed of light in a medium.

Hi Lizard 3678,

Is your question related to a K-12 science fair project? If not, then a different set of online forums will be better able to help you. These forums are specifically for K-12 students, parents, and teachers working on science fair projects.

Lizard3678,

Light is an electromagnetic wave. Check out this website that explains the propagation of an electromagnetic wave through a medium and see if that answers your question.

http://www.physicsclassroom.com/mmedia/waves/em.cfm