Light - Rays and seeing with light

This topic is about how light travels and how we see. The primary concept is that light travels in a straight line, and we see objects as the light is reflected from these objects and into our eyes. The aim is to also remove any misconceptions that pupils may have about light, such as when you switch on my light switch the light is instantly there, or how light is always in the room, much like a puddle of beams, and that it doesn't moves and appears/disappears when the source is switched on.