Sounds and colours are all around us, all the time. And sometimes we don’t really notice. The Sun is in the sky, even on a cloudy day; the stars are always there whether it’s day or night. We talk to each other, enjoy music and use machines; and animals use sounds to communicate too. It’s easy when we are busy at school or work or at home or in between to take for granted that our world is colourful and noisy.
But what are sound and colour made of? Do they move? And, if so, which is faster?
Colour is a word we use to describe the light that our eyes can see. Light is a kind of energy that travels in waves. There are lots and lots of light waves – some that we can see and some that we can’t. The ones that we can see are called ‘visible light’. Our eyes can see three colours – red, green and blue – but by mixing them up we get to enjoy all the colours of the rainbow!
The Earth gets light energy from the Sun, which is a big star at the centre of our solar system. The waves that make up this light energy travel through space at more than 186,000 miles per second! So fast that it takes just 8 minutes and 20 seconds for light to travel all the way from the Sun to the Earth.
Sound is a word we use to describe vibrations that our ears can hear. Something has to move in order to make a sound happen – moving air molecules so that they bump into each other, passing energy along to create a wave.
Lots of vibrations can make sound waves – some that our ears can hear and some that we can’t. The sound waves that we can hear travel through air at about 340 metres per second.
Light travels faster than sound – and you can see this for yourself in some everyday places. For example, if you’re watching a fireworks display you will see the colours of the firework as it explodes in the night sky before you hear the ‘bang’! Or if you’re watching a football match you might see the goalkeeper take a goal kick before you hear the noise of the kick. Or if an aeroplane is flying really fast you might see it before your hear the engine noise.
So when you’re out and about doing your normal things, why not take a minute to look at the colours around you and listen to the sounds and try to spot the times when one is moving faster than the other?!