Students play a modified version of the game "Octopus" to learn about the wavelength and energies of different colours of visible light.
The range of wavelengths of light that the human eye can see is called "the visible spectrum". This includes the colours of the rainbow. Each colour can be explained as a ray of light that is transmitted at a particular level of energy (with a particular wavelength):
|Colour||Wavelength Range (nm)|
The range of wavelength for indigo is around 425–450 nm. It's hard for the human eye to distinguish and is usually considered a subset of violet.
Infrared light has a longer wavelength than red light (above 1000 nm) and can't be detected by human eyes. Some night-vision technologies involve the detection of infrared light, since objects at and around room temperature give off lots of infrared light but not much visible light.
Ultraviolet light has a shorter wavelength than violet light (below 300 nm). It can't be detected by human eyes (but can sunburn skin). A "black light" emits ultraviolet light, which can cause some paint pigments to glow.