Question

1. When a siren is approaching you, how does the observed pitch of the siren compare to what you hear

after it moves past you?
2. Define the Doppler Effect in your own words.
Increase or decrease in the frequency of sound, light, or other waves as the source and observer move
toward or away
3. When a siren is approaching you, how does the wavelength of the waves reaching you compare to the
wavelength that the siren emits?
4. What kinds of waves experience the Doppler Effect?
5. Why are you able to observe the Doppler Effect with sound waves on Earth but not light waves?
6. When stars are moving away from a telescope, what shade do they appear to be compared to the
normal light they emit?
7. What is it called when a galaxy is moving toward us at a very high speed?

Answer 1

1. When a siren is approaching you, the observed pitch of the siren is higher than what you hear after it moves past you.

2. The Doppler Effect is an effect that causes an increase or decrease in the frequency of sound, light, or other waves as the source and observer move toward or away from one another.

3. When a siren is approaching you, the wavelength of the waves reaching you is shorter than the wavelength that the siren emits.

4. The Doppler Effect can occur with sound waves, water waves, and light waves.

5. You are able to observe the Doppler Effect with sound waves on Earth but not light waves because sound waves travel much slower than light waves.

6. When stars are moving away from a telescope, they appear to be redder than the normal light they emit.

7. This phenomenon is called "redshift" when a galaxy is moving away from us at a very high speed.