<>"And, water is called the "universal solvent" because it dissolves more substances than any other liquid. This is important to every living thing on earth. It means that wherever water goes, either through the ground or through our bodies, it takes along valuable chemicals, minerals, and nutrients."<>
The water and air are two different mediums through which the light wave travels.The light wave as we are the electromagnetic waves which are able to travel with out any requirement for the medium.
Moreover, there are few factors like density, temperature(T), pressure(P) etc which are related to a medium characteristics or features which makes it more different to experience for any wave propagating through it.
<u>Water is more denser medium as compared to the air medium. </u>
When the electromagnetic wave passes through a medium of less density such as air,1.2754 kg/m³. As the molecules of air are less compact and they provide less resistance to any wave propagating through it. While, the density of water is about 997 kg/m³. While, the light experiences the bending effect or we can simply say that, the refraction phenomenon occurs when the light enters into a more denser medium that was traveling in a less denser medium before that. There will be some reflection from the surface of the layer which is all due to the surface molecules density of the water medium.
While, the speed of light waves decrease inside the water medium due to the fact that light waves needs more space to propagate through them. As water molecule are more compact providing more resistance,R to the propagation of light waves inside it.