The visible spectrum
I can describe what white light is, and explain why a visible spectrum can be produced from white light.
The visible spectrum
I can describe what white light is, and explain why a visible spectrum can be produced from white light.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- White light from the Sun and light bulbs consists of light of all the colours in the visible light spectrum (a rainbow).
- A transparent triangular prism can split up sunlight into a visible light spectrum.
- The visible light spectrum shows the range of colours that light can have.
- Cone cells in the eye detect colour. There are 3 kinds (R, G and B); each is sensitive to a range of colours of light.
- The colour we see depends on which cone cells are triggered to send a signal to the brain.
Keywords
White light - Light that consists of red, green and blue light in equal amounts so looks white.
Triangular prism - A uniform 3D shape with triangular ends.
Visible light spectrum - A rainbow pattern of coloured light that always occurs with the colours in the same order.
Cone cells - The cells at the back of the eye that detect colour.
Common misconception
Sunlight is yellow(ish), not white.
Show pupils a yellow light (and illuminate white paper beneath a yellow light) and compare it to sunlight to show that sunlight is white.
Equipment
Ray lamps, slits, transparent triangular prisms, red filters (to fit in the ray lamps).
Content guidance
- Risk assessment required - equipment
Supervision
Adult supervision required
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Lesson video
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Starter quiz
6 Questions
cyan
magenta
yellow
white
black