original_query: What is the relationship between the refractive index and the displacement of the rainbow?
query: What is the relationship between the refractive index and the displacement of the rainbow?
answer: Materials with different refractive indices than water produce rainbows with different radius angles.  For example, saltwater has a higher refractive index than rainwater, resulting in a smaller radius for a sea spray bow compared to a regular rainbow.  For materials with a refractive index greater than 2, the first-order rainbow disappears.