How Does Doppler Effect grade 12: Introduction Work?

The Doppler Effect is when sound or light changes pitch or color because the source is moving toward or away from you.

Imagine you're on a playground, and your friend is riding a bike with a bell. When they come toward you, the bell sounds sharper, like it's going faster. When they ride away, the bell sounds softer, like it's slowing down. That’s the Doppler Effect in action!

When the source of sound is moving toward you, each wave gets squished together a little bit. This makes the waves hit your ears more often, so you hear a higher pitch.

But when the source moves away from you, the waves stretch out. That means they hit your ears less often, and you hear a lower pitch.

Think of it like a train passing by you on the tracks:

• As it comes closer, the sound is louder and higher pitched.
• When it goes away, the sound gets quieter and lower pitched.

You can feel this change every time you hear a siren on an ambulance, it’s the Doppler Effect at work!