Final answer:
Light would slow down when it goes from glass to air and from air to water due to the higher refractive indices of these media.
Step-by-step explanation:
When light travels from one medium to another, it can undergo a change in speed and direction. The change in speed and direction is caused by the change in the refractive index of the medium. The refractive index is a measure of how much the speed of light in a medium decreases compared to its speed in a vacuum.
In the given situations, light would slow down when it goes from glass to air and from air to water. Glass and water have higher refractive indices compared to air, which causes light to slow down when it enters these media.