Hi there! Thank you for your question, light is such an interesting topic! The science behind light can get complicated quickly, but we can first think about the most basic principles of light.

Light can either be absorbed, refracted, or reflected. When light is absorbed, the energy from the wave is transferred to the surface. It could be converted to heat. When the light is refracted, it passes through a material. When it passes from one material to a different material, the light actually bends during the refraction process. When light is reflected, it bounces off the surface it hits.

Let us take a common surface like glass, for example. When light hits glass, some of the light is reflected, or bounces off, but most of the lights gets refracted, or passes through the surface (which is why we can see through glass windows). When light hits a surface that is dense like a concrete wall, almost none of the light goes through the surface because the majority of the light is reflected and therefore you cannot see through the wall. When light hits the surface of your eye, it gets refracted, or passes through different tissues in your eye until it is transformed into electrical impulses that your brain interprets as an image!