Download Spectra and the Doppler Effect

Spectra and the Doppler Effect.
ACTIVITY1:
Answer the following questions:
1. What is electromagnetic radiation (EMR)?
2. What type of EMR is emitted by stars and galaxies?
3. Draw the pattern of EMR waves emitted from a star?
4. Define frequency.
5. What type of frequency do high pitched sounds have?
6. What type of frequency do low pitched sounds have?
7. What happens to the pitch of sound as an object approaches an observer? (the
wave is compressed and therefore approaching at higher frequency)
8. What happens to the pitch of sound as an object moves away (or recedes) from
an observer? (the wave is elongated and therefore moving away at lower
frequency)
9. What is the name given to this apparent change in the pitch (sound) as an object
moves towards or away from you?
10. Does this frequency change only occur for sound waves? Explain.
11. What will happen to the frequency (or color) of light if a star is moving towards us?
12. What will happen to the frequency (or color) of light if a star is receding or
moving away from us?
13. What piece of equipment is used to observe Doppler Effects in light?
14. What happens to spectral lines when the star is stationary?
15. What happens to the spectral lines when the star moves away from us?
16. What happens to the spectral lines when the star approaches us?
17. Since most galaxies in the Universe demonstrate Red-Shift, astronomers
conclude that the Universe is __________________.
18. What conditions would have to be met in order for an ambulance with its siren on
not to exhibit the Doppler effect when it passes you?
Conclusion:
Explain why the spectra of some stars shift.