Does light actually slow down in materials with a high refractive index?

Question

I have heard this claim many times in the past, but it seems awefully suspecious to me. What is the actual cause of this phenomenon?

Answer 1

Light does slow down, because materials with a high refractive index are more dense than vaccum, and there's more things for the light to run into.

The velocity of light in a medium is determined by V = c/n, where n is the index of refraction of the medium.

The index of refraction is even dependant on wavelength, which is how rainbows are formed and how prisms work.

Answer 2

Light does slow down fractionally when traveling through clear liquids..to prove this put some water in a bowl...then just put a stick in at an angle you will see that the stick appears to bend..it is because the light falling on the stick through the water is returned to your eyes at different speeds.as it goes deeper in the water to return...Also different colours travel at different speeds ..white light travels at 125,000 miles per second..or around the earth 7 times in one second..I'm just waitng for some-one to split a photon..then maybe we can understand time...