Light travels in waves, and we call this traveling propagation. Propagation of waves has both a speed and a direction, called the velocity. The velocity of light changes depends on the material it travels through.
Light waves can be changed in a few different ways. Reflection is when the waves bounce off a surface and change direction, like when they hit a mirror or pool of water. Diffraction spreads out light waves as well
The refractive index of water is 0.3297 more than air. The refractive index of the medium-water is 1.33 meaning that the molecules in this transparent liquid causes the speed of light to become SLOWER than air.
