By Dr. med. Claudia Schmiemann
So as light is crucial for a human body in order to be alive and stay healthy – what exactly is light???
Some of you may remember a physics lesson at school…some may immediately think of a prism that unfolds all colors of the rainbow.
Let´s have a look at the definition: light is an electromagnetic radiation with wavelength between 380 nm (violet light) and 750 nm (red light) – which is visible for the human eye. And then there is the intensity of light measured in terahertz (between 430-750thz).
It consists of photons, which we can explain as single units of energy. Moreover there is light that is not detectable for our eye like radio waves, ultraviolet, infrared, x-rays, gamma rays etc. .
It was in 1802 that Humphry Davy invented the first “electrical arc lamp”. He was a British chemist who did some fundamental research back in those times and his intention was to create a source of light that would be suitable and safe to use in mines.
Coming back to visible wavelengths we find some characteristics. Colors are on one hand inherent properties of light in the visible spectrum (between 380-750nm) and on the other artefacts of our eye, more precisely of the receptor cells (cones) in layers of our retina.
Let´s have a look at a triangular prism that is able to transform white light into its constituent colors called a spectrum (picture).
To be continued…..
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