Doppler Effect

The pitch of a sound wave relates to the wave's _________________.

An ambulance is driving towards you as you stand on the sidewalk. What happens to the pitch of the siren you hear as it comes towards you?

You are standing on the side of the road when a police car races past you with its siren on. After the police car passes you, what happens to the pitch of the siren that you hear?

Look at the picture. Who is experiencing a higher pitched sound?

Long wavelength sound waves are (in the same medium)...

The Doppler effect happens when a wave-making source has motion relative to an observer. 

As dad escapes from his kids (the gap between him and the kids is getting bigger), he hears them yelling

When the apparent frequency of a wave is higher what happens to the wavelength?

You stand on the sidewalk next to the street. A fire truck is moving towards you. The frequency of the siren on the fire truck is 600 Hz.

What should you hear?

What is the Doppler Effect?