1. An Assessment: Think Pair Share Best procedures: read quietly to yourself (so you don’t give any subconscious clues) Best procedures: read quietly to yourself (so you don’t give any subconscious clues) As the instructor, we read it too, for timing, then ask if anyone needs more time As the instructor, we read it too, for timing, then ask if anyone needs more time If not, it’s time to vote simultaneously—use your fingers, right in front of your chest so others don’t see (anonymous) If not, it’s time to vote simultaneously—use your fingers, right in front of your chest so others don’t see (anonymous)

2. 1. 1. disk of stars with our Solar System located halfway to the edge. 2. 2. disk of stars centered on our Solar System. 3. 3. disk of stars with a bulge that contains our Solar System. 4. 4. sphere of stars centered on our Solar System. 5. 5. sphere of stars with our Solar System located near the edge. An observer far outside our galaxy would best describe our galaxy and the Sun's position in it as a

3. What causes light from a star to be Doppler-shifted? 1. the distance between us and the star 2. the gas and dust between us and the star 3. the speed of the star toward or away from us 4. temperature differences between us and the star

4. 0/0 How does the size of a star near the top left of the H-R diagram compare with a star of the same temperature near the bottom left? A. They are the same size. B. The star near the top left is larger. C. The star near the bottom left is larger. D. There is insufficient information to determine this.

5. The star Rigel is about 100,000 times brighter than the Sun and is about 11,000 degrees. The star Sirius B is about 3000 times dimmer than the Sun and is also about 11,000 degrees. Which star is bluer? A. Rigel B. Sirius B C. They have the same color. D. There is insufficient information to determine this.

6. 0/0 How does the size of a star near the top left of the H-R diagram compare with a star of the same luminosity near the top right of the H-R diagram? A. They are the same size. B. The star near the top left is larger. C. The star near the top right is larger. D. There is insufficient information to determine this.

7. When a star becomes a red giant it becomes much brighter because it is 1. moving closer to us. 2. losing its outer envelope. 3. fusing iron in its core. 4. increasing in size.

8. Which pieces of evidence support the Big Bang theory? A. A. Radioactive dating of meteorites shows an age of 5.5 billion years. B. B. The cosmic background radiation is visible in all directions at a temperature of 3 degrees absolute zero. C. C. Almost every galaxy has a red-shift, with more distant galaxies having the highest red-shift. D. D. The closest galaxies are all blue-shifted, showing that our universe is slowing down. 1. 1. Just A and D 2. 2. A, B, and C 3. 3. Just B and C 4. 4. A, B, and D