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Light sources are everywhere - a torch, a lamp and even the Sun are examples.
A light source is anything that produces light energy. This energy is a type of wave that travels incredibly fast. It travels in straight lines called beams or rays.
We use light sources all the time in our daily lives. The light bulb in your room, the Sun that shines during the day, even the fire on birthday candles are all light sources!
Light sources are needed for humans because we cannot see very well in the dark. The way our eyes work means that we need light rays to bounce off objects and into our eyes, to allow us to see. This all happens almost instantly.
Imagine looking into your bedroom at night. With the light on, you can see everything quite clearly but if you turn the light off...it's hard to see! This is because without light energy, we are left with darkness.
The dark is an absence of light.
We use lights in all different ways - some stronger lights, like floodlights on a football field and some weaker lights, like in a nightlight or a candle on a cake.
Light always travels in straight lines and when it hits an object, it bounces off and the rest of the light continues travelling past the object. This is what creates shadows (we're not going to look too closely at shadows today, we'll get into more detail on that one later!)
Humans have developed reflective surfaces to use instead of lights, in some situations. Reflective surfaces are great for bouncing light back and they are used in all sorts of ways, on bicycles, on firefighter or paramedic uniforms and even on your trainers.
Reflective materials can help us see more in the dark, or be more visible in the dark, without having to put lights everywhere. Can you think of somewhere you have seen a reflective surface?
In this activity, we will be thinking about how we use light and how it travels, allowing us to see. Let's go!
