1. Before the bell rings, in your notes, write out the important aspects of a correctly designed experiment. Make sure to include a description of your variable and control.

2. To understand the Big Bang… We must first start understanding waves and the Doppler Effect!

3. Lets First Experience the Doppler Effect!

4. What causes this sound effect? The Doppler Effect

5. -Here we have a sound wave emitted from an object (car, siren, screaming 9 th grader, etc.) -Each red dot represents an air molecule

6. Now lets consider the waves represented as circles…The waves are distributed evenly spaced in each direction (That means the same frequency!)

7. What happens if we move the sound source? Towards us at 50m/s…

8. Moving towards us faster (100m/s)

9. And faster yet! (300m/s) What is happening to the length between waves that are approaching us?

10. Movement toward an object causes decrease in distance between the waves, which causes an increase in frequency. Higher Frequency = Higher Pitch (Shreekier!)

11. What Happens if the source is moving away from us? -Movement away from an object causes increase in distance between the waves, which causes a decrease in frequency. -Lower Frequency = Lower Pitch

12. Lets sum this sound thing up! With stationary sources, you can hear the same pitch in each direction If sound source is moving toward you, there is a higher frequency. If sound source is moving away, there is a lower frequency.

13. How does this relate to the Big Bang? Electromagnetic Spectrum and visible light

15. Spectrum Named by Isaac Newton

16. Types of spectra

17. How Spectra are formed

18. Spectra of elements Each spectrum is unique, like a fingerprint Spectral Periodic Table Astronomers used spectroscopes to figure out what elements are in stars

19. Spectra for some elements in the atmospheres of stars

20. What elements are in this star?

21. Answer The elements in the unknown star are: Hydrogen and Magnesium

22. Now how can we relate the Doppler Effect to light, and ultimately the Big Bang?

23. Lets look and see if we can figure out the following gases with our spectroscopes? Hydrogen Helium Neon Mercury

24. Doppler Effect on Light

25. Stars and Galaxies

26. The “Red Shift”

28. What does it mean? Stars are moving away from us Universe is expanding

29. What would cause the universe to be continuously expanding?