Why do mirrors reflect?

Answer 1

because they are magic

Answer 2

There are two aspects of a good mirror: (1) the fraction of light that is reflected and (2) the quality of the image. The quality of the image depends on the smoothness of the surface---basically, the surface must be smooth at approximately the size scale of a light wave, which is about 500 nanometers, or about 500 times the size of an atom. If the surface is smooth, the fraction of light reflected depends on the change of index of refraction between the air and the mirror material. At any surface where there is a change in material, some of the light will be reflected, some will be refracted into the material, and some will be absorbed. The mirror material can be semi-transparent (like glass), or partially absorbing (like a metal). The issue is complicated because the index of refraction is, in general, a complex number. Some metals reflect a large percentage of the light (aluminum, for example) and others absorb most of it (nickle). Materials like glass absorb very little of the light, reflect some, and refract some.

I point out that this is an entirely "classical" answer. In reality, the index of refraction of a material is a simplification of its bulk quantum mechanical properties, the interaction between the photon wavefunction and the ensemble of atoms in the mirror. But it seems to me that is way more complex than what is being asked for here.

Answer 3

Anything the eye sees is due to reflected light from the object into your eye, the brain converts the reflection into a picture.

A mirror reflects light.

In the case of a mirror the light from an object hits the reflective surface of the mirror and THEN reflects into your eye.

When you look into a mirror however, your right side is reflected as your left side ... the image is reversed left to right.

Answer 4

Light bounces off all surfaces. The smoother the surface, the more defined the reflection will be because there is less distortion resulting from all the millions of angles on a surface. A mirror has optimum smoothness, so light bounces off it purely and gives our eyes an undistorted light image. Light goes onto our face, bounces off into the mirror, and back into our eyes, where we see it. If you smear the mirror with paste, it becomes a rough surface which is unable to reflect so purely because the paste has so many distortions which bounce the light off in varying directions.

Answer 5

To understand this, you must understand why some things are dark and some things are light.

Dark things absorb light and thus less off it reaches your eyes. Light coloured things emit light and more of light reaches your eyes, and thus they appear brighter.

Mirrors are exceptionally poor at absorbing light, most of which simply 'bounces' off. You are therefore seeing the light that was emited by whatever you can see in them. As mirrors have a polished surface the reflection is not broken up and therefore appears clearer than the reflection from a rough but still reflective surface, such as the surface of a pond when a stone is proffed in to it.

Answer 6

If you look at the back of a mirror you will see that it is silvered. It's not the glass which reflects but the silvering, the glass is just there to protect it. They reflect because light is not absorbed at all and is all bounced back. Things which do not reflect absorb light.

Answer 7

They have a coating of aluminium or silver on the back of the glass. Because this is pure and unoxidised, it is very smooth. Metals always reflect light rather than absorbing it, so all the light will be reflected by the smooth surface of the metal.

Answer 8

This is a great question. Forget what you're told at school.

The incident photon is absobed by an electron on the surface. The photon has momentum and this is imparted to the electron. The electron tries to move with respect to the other electrons in the surface and just below it. This causes electrostatic repulsion between the electrons forced together.
The elecric interation is transmitted by photons and the net result of the electron being pushed back to where it started by electrostatic repulsion is a photon is emitted from the surface. It's i=r properties are due to conservation of momentum.
Now my head hurts

Answer 9

According to Richard Feynmann they don't.They interfere for want of a better word. It is not the same photon coming back as the one that hits the mirror. There are a series of lectures somewhere on the internet that explain the theory behind this in great detail.

Quantum Electrodynamics.

On the other hand it is incomprehensible even to Richard Feynmann. It is merely a set of rules that can be applied that works.

Answer 10

mostly due to the smooth silver / chrome / metallic-whatever backing has a reflects a higher percentage of light than other materials. it reflects the entire spectrum of visible light instead of a single wavelength (like anything that is only one color). The glass or plastic layer just gives it a sturdiness.

Answer 11

It's light bouncing off the polished surface, coloured by all the colours that constitute you, et al, so you see a reflection. I guess that's how people see you in the first place: it's sort of reflected light bouncing off one person to another's eyes.