Light - The Scientific Models

Light is very important to us. It is vital to one of the most important ways we interact with our surroundings - vision. Light enters our eyes, stimulates cells on the retina and enables us to 'see' things.

Understanding what light is and why it behaves as it does is something that has long been an interest to mankind. When we sum up what we know about something from observing it, we create something we call a 'model' to sum up all of the known behaviours and properties.

We know that our 'knowledge' of anything is only partial - so we do not consider it 'the whole truth' about the object or system. It is just one 'model' that helps us remember what we have leart about its behaviour and using our model allows us to predict what will happen if we are on the 'right track' - so using the model we can design investigations to 'refine' our model.

Complex systems often have several models that are used to describe them - each model is able to help us understand one aspect of the system.

Models of Light

We know that light is a form of electromagnetic radiation - it is the tiny part of the electromagnetic spectrum that we can detect with our eyes. So it is a wave. But it is often convenient to model or describe light in a number of different ways, not just as a wave. For example, in spectroscopy and quantum mechanics, light is often described not as a wave, but as a particle.

When looking at light it is sometimes useful to use the 'Ray Model' or ' Wave Model' or the 'Particle Model' (also called the Corpuscular Theory) - the chosen model depends on the aspect we want to look at - and it helps us predict what light will do in certain situations - but none of the models totally encapsulate every aspect of light's behaviour.

Whether light is a particle or a wave was hotly debated by scientists - but today we realise that it is both a wave and a particle - see wave-particle duality - you study this at A-Level.