In this deck, we'll explore the fascinating world of light and lenses. We'll start by looking at how light reflects off different surfaces, and how it bends, or refracts, when it travels from one material to another. Then, we'll discover how convex and concave lenses work to form images. We'll also learn the crucial difference between real and virtual images. A key skill in this topic is drawing ray diagrams, which we'll explain conceptually. However, drawing them accurately is best learned with pen and paper, so we recommend practising this at a desk.

Let's begin with reflection. When light hits a surface, it bounces off. The type of reflection depends on the surface. A very smooth surface, like a mirror, causes specular reflection. All the light rays bounce off at the same angle, creating a clear image. But a rough surface, like paper, causes diffuse reflection. The light rays scatter in all directions, which is why you can't see your reflection in a piece of paper.

For specular reflection, there is a simple rule called the law of reflection. It states that the angle of incidence is equal to the angle of reflection. The angle of incidence is the angle between the incoming ray and the normal, which is an imaginary line at a right angle to the surface. The angle of reflection is the angle between the reflected ray and the normal.