Hearing Sciences
A model of a right ear

What is sound?

Sound is all around us, but what is it, and how is it made?
 

Have a look at this video to find out about what sound is and how it's made.

You will need to open the video in YouTube to see the captions: use the 'Copy link' button in the top right of the video and paste this into your browser. We have also provided the transcipt below.

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What is sound? Next time you're out  for a walk close your eyes and listen. What can you hear? Maybe it's cars driving past you, maybe it's a bird flying through the air, or maybe it's you whistling as you walk. These are all examples of sound, but what is sound? Sound is a kind of wave. No not like that. It's more like a ripple  that moves from one place to another. Okay sort of like that. Think of a stretched slinky. If you give one end of it a flick, you can make a pulse move along to the other end. Sounds a bit like this. Actually sound isn't quite like this. Instead of flicking the end of the slinky up and down, sound waves are more like giving the slinky a push and a pull. When things make sounds, tiny bits of stuff in the air called particles get squashed together, or compressed, and get stretched apart, or rarefied. This pattern of squashing and stretching  carries on through the air between particles, as they bump into each other until we hear it with our ears. This is what we call a longitudinal wave. But it's usually easier to think of sound waves wiggling up and down instead. This is what we call a transverse wave. Now  let's pause our sound wave for a moment. We can change the shape of the wave to affect  how it sounds. By changing the height of the wiggles we can change the volume. If we make the wiggles bigger, the sound gets LOUDER. If we make the wiggles smaller, the sound gets quieter. We call the height of the wave its amplitude. Or we can change how long or short  the wiggles are. If the wiggles get closer together, the sound gets higher. [Rising tone] If the wiggles get further apart, the sound gets lower. [Falling tone] This is called the frequency of the wave. But how do we make sounds? There are four main ways of making sounds. The first one is that we can knock two hard objects together, like claves. [Knock from 'Frozen'] "No!" The second one is that we can pluck or hit a  stretched string, like in a piano, guitar, or ukulele. ['Duelling Banjos' plays on ukulele] The third one is that we can hit a  stretched sheet or membrane, like a drum. [Drumroll] And the fourth one is that we can blow  air through a pipe, like in a saxophone. ['Baby Shark' plays on saxophone] "No!" See if you can think of different musical instruments and work out which way they make sounds. To learn more about sound and hearing, check out the Ear Facts page on the University of Nottingham website. There you'll find lots of information along with some fun activities. You can also submit a question about sound and hearing  and get answered by a real scientist. And you might even be able to find out how you can make your very own musical instrument out of a carrot. ['Shave and a Haircut' plays on carrot]
 

Then, try and work out how different musical instruments produce sound, such as the violin, flute, trumpet, timpani, xylophone.

Or, you can have a look at the instructions below to see how you can make your very own musical instrument out of a carrot!

Make your own carrot ocarina

You will need a large carrot (15cm by 4cm minimum), a 2.5cm drill bit and a 4mm drill bit, and some sharp knives

Cut off bottom 3-5cm of carrot, put aside. Use large drill to bore middle out of the large piece of carrot.

Carve the sides off the small end so it fits very snugly into the bore. In the carved part, cut a 1.5cm long, 0.5cm wide, and descending 0.3-0.5cm deep groove.

Cut a imilar notch in the main bosy, about 0.5cm from the open end, all the way into the bore, and reinsert the small piece to line up. Try blowing this mouthpiece.

Use the small drill bit to drill holes in the main body, clearing out the bits. These will change the sound.

A diagram of holes designed to play a tune on the carrot ocarina

 

Download the instructions as a PDF

Learn more about hearing

 

 

Hearing Sciences

Division of Clinical Neuroscience
School of Medicine
University of Nottingham
Medical School, QMC
Nottingham, NG7 2UH


telephone: University Park +44 (0) 115 74 86900
Ropewalk House +44 (0) 115 82 32600
Glasgow +44 (0) 141 242 9665 email:hearing-research@nottingham.ac.uk