2. The Doppler Shift

4. The Visible Spectrum White light splits into the colors of the rainbow when passed through a prism.

5. The Visible Spectrum Red Orange Yellow Green Blue Indigo Violet

6. The Visible Spectrum R O Y G B I V

7. I would like to introduce... RO Y G BIV

8. Sometimes it gets reversed... RO Y G BIV

9. Sometimes it gets reversed... RO Y G BIV

10. Sometimes it gets reversed... VI B G YOR But the order makes no difference. (Roy’s evil twin brother.)

11. There’s more to the spectrum than what you can see.

12. Radio Waves Microwaves Infrared (IR) Ultraviolet (UV) X-Rays Gamma Rays There’s more to the spectrum than what you can see.

13. Pure White Light

14. Glowing Gas Neon Light The “fingerprint” of an element.

15. Glowing Gas Hydrogen Light

16. When sound is made by a stationary object, you hear a certain frequency... Insert constant sound here

17. If you could see it, it would look like this...

18. But when the sound moves towards you, it sounds higher in pitch. Waves get compressed.

19. The faster the object moves, the higher the pitch. Waves get compressed more.

20. When the object moves at the speed of sound, the waves overlap......and you get a sonic boom.

21. Fly faster than sound, and you’re gone before the boom is heard.

24. An on-line visualization: http://www.phy.ntnu.edu.tw/java/Dopple r/Doppler.htmlhttp://www.phy.ntnu.edu.tw/java/Dopple r/Doppler.html

27. When the sound moves away, it sounds lower. Waves are stretched.

28. What it Sounds Like. Car 1 Bike 1 Prop 1 Whine Jet 1 Deep Jet Prop2 Race1 Race2 Mortor Prop2 Race1 Race2

29. The same shifting happens with the light from a moving star. Lower FrequencyHigher Frequency

30. The spectrum of hydrogen that is from a stationary source.

31. When the star is moving closer... Stationary Hydrogen “Blue Shifted” Hydrogen from star moving towards Earth.

32. And when a star moves away from us... Stationary Hydrogen Lines are shifted to the red end.

33. And when a star moves away from us... Stationary Hydrogen Lines are shifted farther to the red end. Faster

34. Since the universe is expanding... All distant objects have a red shift. The farther the object, the more extreme the red shift.

35. Astronomers use this relationship between distance and speed to measure the distance to distant stars and galaxies.