Can you use the Primary colours of red blue and yellow to make more colours? Try using some paint and create hand prints to show the colour mixing.
Here is another fun activity you can try that also involves colour mixing:
Materials needed: zip lock food bags, poster paints, tape
Method:
Place different colour combinations of the primary colours into a zip lock bag. Seal and tape to a flat surface. The pupils can then have fun squishing it all together to make a secondary colour.