Question

How is the speed of light affected as light passes at an angle from air to water

Answer 1

They are said to be “denser” than air. what happens is that light slows down when it passes from the less dense air into the denser glass of water. this slowing down the ray of light also causes the ray of light to change directions. it is the change in the speed of the light that causes refraction.

Answer 2

The index of refraction of water (1.33) is greater than that of air (1.00).
With that said the index of refraction is related to the velocity of light by:

$n = \frac{c}{v}$

where n is the index of refraction, c is the speed of light in a vacuum and v is the velocity of light in the medium.
As c is constant we can see that the speed of light in a medium is inversely proportional to the index of refraction

$n \: \propto \: \frac{1}{v}$

therefore the medium with the lower index of refraction will have the greatest velocity of light (Air).