Video title: How do sounds travel?

In order for us to hear someone singing, the sound has to travel from the mouths of the people singing, all the way to our ears.

But how does sound travel?

How does sound travel?

When people sing their vocal cords vibrate, creating vibrations in air molecules.

vibrations

The vibrations move through molecules as waves.

waves

These waves are called compression waves because the air molecules are compressed together.

compression waves
molecules compressed

As sounds travel, we say the waves are transmitted.

transmitted

Sound waves always need a medium to travel through.

The medium can be a gas like air, a liquid like water, or a solid like a wall.

Sound waves travel at different speed depending on the medium.

sound waves
travel at different speeds
in gas, liquids and solids

The speed of sound.

The Speed of Sound

Sound travels faster through a solid than it does through a liquid.

But the speed of sound is slowest in a gas.

speed of sound
fastest in solid
slowest in gas

No matter the speed, sound is always transmitted as compression waves from a source through a medium.

transmitted
compression
medium
speed

Find out that sound waves always need a medium to travel through.

Learning points

• Sound waves are known as compression waves.
• Sound waves travel at different speeds depending on the medium.

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