Lesson 1: Concept of light

Outcomes

By the end of this course you will:

1. Know what light is
2. Understand the role that photoreceptors play in your ability to see
3. Be able to identify different sources of light and provide examples of each

Your sight is one of the five senses that most people are blessed to have (the other four being hearing, taste, touch and smell). 

Have you ever considered how important light is in your everyday life? Have you sometimes wished that it was lighter when you walked home from a late soccer match and you've struggled to see where you're going?

In this course you will explore the concept of what light is, some of the different sources of light as well as being able to differentiate between luminous and non luminous bodies.

What is light?

The reason you can see is because there is an interaction between light and your eye. When you look at an object, the light is reflected off that object and enters your eye: 

Image: Needpix (CC)

Let's dig a little deeper into the photoreceptors.

Photoreceptors

 Your eye has two types of photoreceptors namely rods and cones:

Rods are responsible for your night vision and are highly responsive to the stimulation of light. Rods are able to detect outlines, shapes, movement and contrasts but are not able to determine colour. You may have noticed that when the light is very low that you can see shapes but not always the colour of them?

Image: Wikimedia Commons (CC BY-SA)

Cones are responsible for your colour vision but require a large amount of light to be stimulated. 

Click on the link below to find out more interesting features of light.

Before moving onto the sources of light, watch the short YouTube video below which sums up what we have covered so far.

Twig Science Reporter. (2015). What is light? (Standard YouTube licence)