william herschel discovered infrared waves in the electromagnetic spectrum.
who discovered infrared waves in the electromagnetic spectrum?
william herschel
the first discovery of electromagnetic radiation other than visible light came in 1800, when william herschel discovered infrared radiation. he was studying the temperature of different colors by moving a thermometer through light split by a prism. he noticed that the highest temperature was beyond red. he theorized that this temperature change was due to "calorific rays", a type of light ray that could not be seen.
electromagnetic spectrum
above infrared in frequency comes visible light. the sun emits its peak power in the visible region, although integrating the entire emission power spectrum through all wavelengths shows that the sun emits slightly more infrared than visible light. by definition, visible light is the part of the em spectrum the human eye is the most sensitive to. visible light (and near-infrared light) is typically absorbed and emitted by electrons in molecules and atoms that move from one energy level to another. this action allows the chemical mechanisms that underlie human vision and plant photosynthesis. the light that excites the human visual system is a very small portion of the electromagnetic spectrum. a rainbow shows the optical (visible) part of the electromagnetic spectrum; infrared (if it could be seen) would be located just beyond the red side of the rainbow with ultraviolet appearing just beyond the violet end.
electromagnetic spectrum