A handheld LED coloured-light mixer for students to learn collaboratively the primary colours of light

Abstract

To overcome students' inaccurate prior knowledge on primary additive colours, a coloured-light mixer has been constructed to enable students to observe directly the colours produced and reach the conclusion by themselves that the three primary colours of light are red, green, and blue (NOT red, yellow, and blue). Three closely packed tiny light-emitting diodes (LEDs) producing primary colours are combined with green intensity varying circuitry to generate the standard colour-triangle secondary colours and various shades ranging from yellow to orange and pale blue to cyan. In the laboratory, students worked collaboratively, predicting, observing and explaining, and finally discussing until there was a consensus. © 2009 IOP Publishing Ltd.