Sunlight and moonlight appear as white light because they contain a mixture of different colors or wavelengths of light. When sunlight or moonlight passes through a transparent medium like glass, its behavior depends on several factors, including the properties of the glass and the angle of incidence.
When white light passes through a glass surface, it can undergo three primary phenomena: transmission, reflection, and refraction.
Transmission: Some of the light can pass through the glass without being significantly affected. This is known as transmission. The glass is transparent to certain wavelengths of light, allowing them to pass through and reach our eyes. This is why you can see sunlight or moonlight through glass.
Reflection: A portion of the light can be reflected back from the surface of the glass. This is known as reflection. The reflected light can contribute to the overall brightness or appearance of the glass surface. However, if the glass is properly designed or coated to minimize reflection, you might see less reflected light.
Refraction: Refraction occurs when light passes from one medium to another with a different optical density, such as from air to glass. The change in optical density causes the light to change direction. The amount and direction of refraction depend on the angle of incidence and the refractive index of the glass. Refraction can cause the light to bend as it passes through the glass, but it does not change the color composition of the light significantly.
Overall, the combination of transmission, reflection, and refraction allows us to see sunlight or moonlight through glass, even though they are perceived as white light. The glass acts as a medium that allows some of the light to pass through while reflecting or refracting a portion of it.