Welcome to practical physicsPracticle physics - practical activities designed for use in the classroom with 11 to 19 year olds

Spectra and colour

Experiments in this collection begin with Newton's experiments, showing that white light comprises the full spectrum of colours. One experiment hints that the spectrum continues beyond the visible. Line spectra, in sunlight and from other light sources, become visible using gratings. Finally, there are experiments that introduce additive and subtractive colour mixing.


A simple spectrum

Demonstration spectrum

Investigating the spectrum with an electronic detector

Herschel’s infra-red experiment

Spectra formed by gratings

Absorption spectrum of sodium

Simple spectrum of sunlight

Absorption lines in the spectrum of sunlight

Understanding colours

Additive colour mixing

Mixing coloured light


Beyond the visible spectrum

Related Guidance

Classroom management in semi-darkness

The electromagnetic spectrum

Learning from spectra