The Visible Spectrum
Use this site to demonstrate or explore aspects of the visible spectrum.
The Visible Spectrum Page
Explore the relationships between frequency, wavelength and perceived colour for the part of electromagnetic spectrum from just below to just above the range of human vision.
Move the slider below the spectrum image to change frequency. The colour associated with the selected frequency is shown in the rectangle at the top left of the screen. The extremes of the scale are in the infra-red and ultra-violet ranges, so no colour is perceived at the extremes.
The human eye typically responds to frequencies from about 400–790 THz. This corresponds to wavelengths of about 380 to 750 nanometers. As with normal human vision, the colours fade near the edges of the visible range.
The relationships between values are accurate. For example, The displayed frequency and wavelength correspond to each other, and the colour shown is a close approximation to the displayed frequency. However, the wavelengths of the light waves are far too short to show on a screen. The intention of the wave graph is to make the relationship between frequency and wavelength easy to see, not to accurately reproduce real values.
The Emission Spectra Page
Click on an element on the periodic table to view the line emission spectrum for that element. Elements that are greyed out do not have images available.
Spectrum images are in the public domain courtesy of McZusatz via Wikimedia Commons.
The periodic table reflects the official IUPAC version at November 2020.