2023-11-21 05:38:50
«Mirror, mirror, who is the most beautiful in the kingdom?» This is the phrase with which the evil witch in the story of Snow White persistently tortured her mirror. A story published by the Brothers Grimm in 1812 and brought to the big screen more than a century later by Walt Disney.
The oldest mirror – from the Latin speculum – that we have news of was found in Anatolia (Turkey) and has been dated to around 6000 BC. Later, the Egyptians, the Etruscans and the Romans would use them to burnish copper, plant or bronze until they achieved a completely smooth surface.
In the Middle Ages, the fame of the mirror was greatly devalued, since Christianity instilled in society the fear of sinning with vanity if they made excessive use of it.
Throughout the 14th century, glass mirrors became popular, made by artisans on the Italian island of Murano and consisting of a well-smoothed sheet of glass on which silver was poured. A mirror model that still persists today.
The key is to reflect without dispersion
Light is made up of photons, particles that travel at a constant speed – that of light – and oscillate at different frequencies depending on their energy. When light hits an object, three things can happen: it goes through it completely, in which case it is transparent, it goes through it partially, when the object is translucent, or it does not go through it, in the case that we are faced with an opaque object. .
Let’s stay now with the opaque objects. When light falls on them, part is absorbed by the surface and part is reflected. The wavelength of the latter is what determines the color with which we perceive the object. That is, we see a green pear because the skin absorbs all colors except green, which is what is reflected and what is detected by the color receptors (cones) that we have in our retina. Now, why don’t we see ourselves reflected in the pear?
The pear lacks a completely smooth surface, it has roughness, this determines that the light that falls on it and is reflected does so at very different angles, in Román paladino, the green color spectrum “bounces” in all directions. It is precisely this dispersion that is responsible for our image being totally unrecognizable.
Let’s now turn our attention to the mirror. It has a polished metal surface that is behind the glass, which acts as a protector to prevent the metal from being scratched, since in this case it would cause dispersions. The metals most commonly used in the production of mirrors are alloys made up of two parts of copper and one of tin.
As the mirror has a smooth surface, all the photons it receives are reflected and always do so in the same direction, so that an image is projected that is extremely faithful to reality, with one insurmountable difference: the right side of the mirror. Object is located on the left side and vice versa.
Nature also has its mirror
Gorillas, bonobos, orangutans, bottlenose dolphins and killer whales share, among many other things, the ability to recognize themselves when their image is projected in the water, the mirror of nature.
The physical phenomenon of seeing something reflected in water is known as water reflection. This is because water is a reflective surface capable of reflecting part of the light that reaches its surface.
And we see our reflection in the water, basically, because the surface is so smooth that, when the light rays bounce back and forth, they do so without distortion, just like what happened in the mirror. This, obviously, is more complicated to accomplish on days when there is wind, since the surface of the water is altered.
#reflect #water #mirrors