The way we move can really change how we hear sounds, and that's called the Doppler Effect! Let’s break it down in a straightforward way:

• When Something Comes Closer: If a sound source, like an ambulance, is moving toward you, the sound waves get bunched up. This makes the sound you hear have a higher pitch. It’s like how you notice the siren of an ambulance sound higher as it comes closer and then turns lower as it drives away.

• When Something Moves Away: If the sound source is going away from you, the waves get stretched out. As a result, you hear a lower pitch.

This happens because the movement changes how far apart the sound waves are. To understand it a bit more, there’s a formula that scientists use to figure out the changes in sound frequency.

Here's the formula:

$f' = \left(\frac{v + v_o}{v - v_s}\right)f$

In this formula:

• $f'$ is the frequency you hear.
• $f$ is the sound’s original frequency.
• $v_s$ is the speed of the source.
• $v_o$ is the speed of the observer (that’s you!).

Isn't it amazing how just moving a little can change the sounds we hear?