Re: The color of light
Pretty sure the number of colours in visible light is not the important thing here. The point is that this is a very common, very basic plant biology experiment that gets repeated everywhere.
The best part is it's accurate too! Plants generally undergo photosynthesis faster under red light, thereby growing more, but more slowly under green light. The green pigments are able to absorb the wavelengths of red light, but not green light. With blue and yellow it's somewhere in between, depending on the plant.
Awesome. Totally getting this if it gets printed.