How do we make and hear sound?

To demonstrate how to make the sound that comes out of a brass instrument, let’s start with a ukulele! How do we make a sound with a ukulele? Answer: we pluck a string, the string vibrates very fast (in a blur) and makes the air around it vibrate.

The room is full of air. We can’t see it but we can feel it if we wave our hands about or the wind blows. Billions and billions of tiny molecules of gas, oxygen, nitrogen, carbon dioxide and other gases, vibrate and jostle against the molecules around them, making them vibrate too. This creates a wave of sound that travels out across the room like ripples on a pond when you throw stone into it.

The sound wave reaches our ears and makes our ear drum vibrate. The ear drum is a tiny membrane just like the surface of a drum. When the vibration reaches it, signals travel from the ear along nerves into our brain and we hear sound! Which when you think of it is absolutely amazing and mind blowing!

We pluck the string, it vibrates and makes the air around it vibrate sending a sound wave across the room to our ear and into our brain. BUT … cornets and trombones don’t have strings! So how do we make sound with a brass instrument? With our lips by buzzing!

Did you know that sound cannot travel through space because there is no air in space and nothing to vibrate. But sound can travel through a wall, the ground or your body!

All sound is created in his way, not just music. When we speak or sing, we push air from our lungs across the “vocal cords” in our throat making them vibrate to produce sound waves just as if we had plucked a string on a ukulele or buzzed into a cornet mouthpiece. For more information see vocal cords on simple wikipedia.

When we whistle, we blow air through our lips in a way that makes the air vibrate without our lips vibrating, which is different to buzzing. To find out more visit how to whistle on wikihow.

For more details about how our ears work see this article from Nottingham University.

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