State in brief what we can demonstrate by rotating Newton’s colour disc very fastly.

When rotating Newton's colour disc rapidly, we can demonstrate the phenomenon of colour mixing and the persistence of vision. Initially, the disc has sectors painted in different colours. When turned quickly, the individual colours blend together due to the rapid motion. This blending occurs because our eyes retain the image for a brief moment, and when the sectors move quickly enough, our visual perception combines the colours and perceives them as white light.

This experiment illustrates that colour is not intrinsic to objects but rather arises from the interaction of light with our eyes and brain. It also exemplifies additive colour mixing, where different colours of light add together to create a perceived new colour. Hence, the rapid rotation shows how our visual system can reconstruct colour from its components when presented in quick succession.