Before you delve into any sort of lesson dealing with colour, perhaps you should take a look at this. I have done so much with pencil crayons. They are so easy to use, to manipulate for mixing new colours, without the mess at clean-up time, and they accomplish the same results, especially for the adolescent mind.
This is a reference tool, not so much a lesson plan, although there are teachable activities included. CLICK HERE to connect with other lessons using pencil crayons:
Colour Mixing