Why Does Light Bounce Off of a Mirror?

Light absorption

Most objects absorb light waves to some degree, while the light they do not absorb appears to us as its color. So-called "visible light" is defined as those light waves (380 to 750 nanometers) that can be discerned by the normal human eye; humans can also perceive a combination of these light waves, though these are not technically included in the spectrum of visible light. Other animals and technologies can perceive light that is longer than red (infrared) and shorter than violet (ultraviolet).

Polished surface

A mirror has two important features that allow it to reflect instead of absorbing visible light. The first of these is its highly polished surface, which in typical mirrors is made to be smooth so that it does not distort light. The most common base for a mirror is glass, which allows light to pass through the mirror to its back.

Silvering

After visible light has passed through the glass front of a mirror, it strikes the reflective back. Once created by an application of silver, it is now more commonly created with a layer of powdered aluminum, though the name of the process has not changed. This surface reflects the visible light back through the glass, where it is then processed by the eye.

Other mirrors

Some mirrors are curved to refract light, either to focus or scatter it. Additionally, there are mirrors which are designed to work with light outside the visible light spectrum (infrared and violet).

Resources

• Info on light