Humans have always been fascinated by light and what happens to it as it passes through transparent materials or reflects from a shiny surface. Simple mirrors have been found in archaeological sites from China to Egypt and lenses have been used for more than 3500 years to start fires by focussing sunlight.

We are all familiar with light, we see objects and we recognise their colours and although it seems a simple phenomenon there are many aspects which require very sophisticated physics and mathematics for their explanation.  However, there are many aspects of light which may be explained by some very elementary ideas. There are, essentially, two descriptions of light: the wave model and the ray model. We shall concentrate here on the ray model although we shall spend just a little time talking about the idea of light as a wave.

We describe reflection and refraction and introduce Snell’s laws in a manner appropriate to a primary level. The practical exercise will include tracing a light through a glass block using optical pins and parallax. By measuring suitable lengths and angles we obtain an estimate for the refractive index of glass.

PRIMARY: reflection, refraction, waves of light.

Copyright Maths Discovery 2015