This one-off class covers how our sense of vision works.

We begin with a brief overview of light and how it is a type of wave. Then we consider how an eyeball forms an image of the world around us on our retinas. Nerve cells there turn the light into electrical signals and send them to our brain, which interprets those signals as vision.

We'll discuss how light of different wavelengths is sensed as different colours, thanks to the colour-sensing cells in the retina. This leads to an understanding of what colour really is, and why the colours we see depend on the biology of our eyes and brain. We'll conclude by talking about some interesting colour phenomena, including how display screens produce so many colours from just red/green/blue, and what happens when you mix coloured paints. We'll answer the question: "Is what other people see as red the same as what I see as red?"

Material will be presented with illustrated slides, with time for students to ask questions to ensure full understanding. No prior knowledge is required.