Light - Visible - 14-16

This collection explores visible light, in particular colour, suitable for ages 14-16.

About visible light: The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 390 to 700 nm. In terms of frequency, this corresponds to a band in the vicinity of 430–770 THz.

Resources in this collection:

  • Chemiluminescence - Oxidation of Luminol: In this classic demonstration, from the Royal Society of Chemistry, a solution of luminol is oxidised by sodium chlorate giving out a blue glow without an increase in temperature. 
  • Colour and Temperature of Stars: This Teaching Astronomy and Space video clip, from the Institute of Physics (IOP), Teachers TV and the Science and Technology Facilities Council (STFC), shows how it is possible to illustrate how the light emitted by a star is related to the star's temperature. Using a filamernt lamp and a variable resistor, the lamp glows first red, then yellow and eventually white as the voltage is increased and the filament temperature rises. 
  • Colour Mixing: This video from the Royal Institution describes how colour mixing works. Colours of light cannot be mixed in physics but different cones in your eyes are sensitive to different colours. 
  • Light and Matter: Models and Applications: Electromagnetic waves show a huge range in terms of frequency and wavelength, but the same basic principles underlie wave behaviour: understanding one application can help us understand others based on the same principle. The booklet provides an overview of some of the models we use in discussing phenomena such as reflection, diffraction patterns, polarisation and emission spectra, and provides a practical introduction to how electromagnetic radiation can be used to study objects and matter.
  • Mixing Colours: Visible light is the region of the electromagnetic spectrum with which we are most familiar. We are able to distinguish between different frequencies of light because of our perceptions of colour. The booklet looks at the scientific principles of colour technology, including computers and mobile phone displays, digital cameras, printers and printed materials. The activities include splitting and combining light, how filters work, the resolution of the human eye, how colours are created in printed materials, and mixing dyes and inks.