What happens when light hits a prism

Refraction and spectral colors

If a light beam falls through a glass prism, the beam is refracted twice, the first time at the transition from the optically thinner to the optically denser medium (air-glass) and the second time at the transition from the optically denser to the optically thinner medium (glass-air). Different wavelengths are refracted to different degrees. If "white" light, e.g. sunlight, falls through a prism, a continuous spectrum is created which comprises around 300 color nuances that can be distinguished by the human eye. These spectral colors cannot be further split optically, which is why they are also called spectrally pure.

Refraction of white light into the spectral colors

Light spectrum


If all the colors of the spectrum are brought together again through a lens, "white" light is obtained again. In this type of optical color mixing, the individual wavelengths are added together to form "white" light, which proves that "white" light consists of the different wavelengths of the spectrum.

Newton's particle model

As early as 1676, the physicist Isaak Newton demonstrated, both experimentally and theoretically, that "white" light was broken down into 7 different colors of the spectrum. However, Newton started from a physical model that describes light as a particle and, due to its influence, prevented the wave model, as it was represented by Thomas Young or Cristiaan Huygens (1629-1695), from being recognized for a very long time.

Young's trichromatic theory of color vision

In 1827 the English physicist Thomas Young discovered that by mixing the spectral colors red, green and blue-violet, depending on the dosage, the sensory impression of all other colors can be created.

See also:

Additive color mixing,

Color perception