Doppler Effect

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

• Amplitude

• Frequency

• Wavelength

• Period

What is the Doppler Effect?

• A change in frequency due to the relative motion of a wave source and an observer

• When a wave overlaps with another wave

• When a wave bounces off of another object

• When a wave bends due to traveling through a different medium

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

• It increases

• It decreases

You are driving in a car and honk the horn at a person standing in the street. As you approach the person, what happens to the pitch of the horn according to you in the car?

• It increases

• It decreases

• It stays the same because you are in the car moving with the sound.

Light can change color due to the Doppler Effect.

• True

• False

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?

• It increases

• It decreases

• It turns red

An astronomer looks at a star in the night sky. Based on his calculations the star's light is shifting towards the color blue. What does this mean about the star?

• It's moving towards the astronomer

• It's moving away from the astronomer

• It's not moving at all

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

• Observer A

• Observer B

• There's no difference

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

• Observer A

• Observer B

• There is no difference

Long sound waves are...

• high pitched
• low pitched
• medium pitched