March 19 & 20

1. March 19 & 20 • Do Now – Take a clicker; set aside for end of class. Take a look at your ‘What The ?!’ Question sheet. • Are there any questions you are able to answer? If so, answer them • Are there any questions you still have? If so, write them down • HW– Prep for your open notes test on CH 9 through everything we’ve learned about universal gravitation • Objectives– Scale of Universe Analogies; YouTube Videos, Assign 3rd MP project, Review HW due today, test prep

2. The TWO-INCH Universe A powerful set of analogies to examine size and distance in astronomy Source: smithsonianeducation.org

3. Earth’s diameter = 8,000 miles • QUESTION: If Earth is just two inches wide, how big would the Moon be at this scale?

4. Moon = ¼ inch! • actual diameter = 2,000 miles QUESTION: At this scale, how far apart should they be?

5. 5 feet! • actual Earth-moon distance = 240,000 miles …1 light second! • QUESTION: How big should the sun be in this analogy?

6. A minivan (16 feet across)! • Actual Sun diameter = 875,000 miles • QUESTION: If the 2-inch Earth were placed in the middle of the classroom, where would the minivan need to be parked to represent the position of the sun at this scale?

7. 6 football fields away! • The van could be parked at Robbinsville-Edinburg Road! • Actual Earth-Sun distance = 93,000,000 miles or 8 light minutes

8. NEW ANALOGY • Scale down the minivan sun into a 2-inch sun • QUESTION: At this scale, how big would Earth be?

9. A grain of salt! • QUESTION: How big would the moon be?

10. A speck of dust! • QUESTION: How far away would this “speck of dust” moon be from the “grain of salt Earth”?

11. ½ inch! • QUESTION: How far away would the sun be from the “grain of salt” Earth?

12. 20 feet!

13. New Analogy: 2-inch Solar System • Sun speck in center, planets would be invisible at this scale! • Actual solar system size = 7,000,000,000 miles (10 light-hours)

14. Next nearest star at this scale (Proxima Centauri) would be 2 football fields away! • Actual distance = 25.8 trillion miles or 4.3 LY • Sun is 1 of billions of stars in our galaxy • QUESTION: At this scale, how big is the Milky Way?

15. About the size of North America • Actual Milky Way size = 100,000 LY • At this scale, if the tiny dot of light at the center of the solar system were a grain of salt, a teaspoon of the salt would represent about 100,000 of the Milky Way’s 200+billion stars!

16. New Analogy: The Realm of Galaxies • Side note: Andromeda galaxy is a galaxy that is very near the Milky Way and is seen as a single smeary light to the naked eye • Actual Andromeda size = 1.3 million trillion miles (220,000 LY) • Shrink the “continent-size Milky Way” down to 2-inches • QUESTION: If Milky Way is 2-inches big, what is the distance between these two galaxies?

17. ~ 5 feet! • Actual Milky Way-Andromeda distance = 15 million trillion miles (2.5 million LY) • At this scale, individual stars in these galaxies would not be visible even with a microscope • At this scale, the deep space galaxies seen by Hubble would be 4 miles from this classroom! • So…QUESTION: How big is the universe? • Let’s watch: http://htwins.net/scale2/

18. YouTube Videos • Take a handout and scan the questions NOW! You will be expected to answer them as we watch the videos as a class • “Life Inside the Space Station” http://www.youtube.com/watch?v=nGefSuwGylg • “NASA Zero-G Fun with the Vomit Comet KC-135 Reduced Gravity”http://www.youtube.com/watch?v=MMV_a7Olf2c • “Space Toilet” http://www.youtube.com/watch?v=HUe2HcFUPSo&feature=related • “Hilarious G-Force training” http://www.youtube.com/watch?v=Yjg6mRFzZzE • “Astronauts on the moon” http://www.youtube.com/watch?v=FAqjys-cxoU

19. 3rd Marking Period Project • Take a rubric • Change the 1st bullet point to 100 points! • You will have ONE class period immediately following spring break to work on this. It is in your best interest to do some of the work over spring break. • QUESTIONS?

20. HW Due today… • Take out your HW and get your clickers ready • Choose the answer that best corresponds with your answer.

21. 21. Comment on whether or not this label is cause for concern… • Yes! Definitely cause for concern • Nope – not concerned • I have no clue what is going on 10 Countdown

22. 22. Earth and moon are grav. attracted..… • The more massive Earth attracts moon w/ a greater force • The less massive moon attracts earth with a greater force • The forces are equal / the same

23. 23. Woman weighs 500 N; what is the grav. force on her? • More than 500 N away from Earth’s center • Less than 500 N away from Earth’s center • More than 500 N toward Earth’s center • Less than 500 N toward Earth’s center • 500 N toward Earth’s center • 500 N away from Earth’s center

24. 24. If gravity from sun on planets disappeared… ? • Planets would immediately stop moving and stay where ever they are • Planets would start moving straight towards sun and crash into it • Planets would take a tangent path 10 Countdown

25. 25. Does the moon get 1.4 mm closer to the earth each second? Would it get closer if tangential velocity were reduced? … ? • Yes, yes • No, no • No, yes • Yes, no 10 Countdown

26. 26. If the moon were 2x as massive, would force of earth on moon be 2x as large? Of moon on earth? • Yes, yes • No, no • No, yes • Yes, no 10 Countdown

27. 29.Jupiter is 300x as massive as earth but you only weigh 2.5x as much (not 300x as much). Why? • Because Jupiter is more massive than Earth • Because Jupiter is less massive than Earth • Because Jupiter has a bigger radius than Earth • Because Jupiter has a smaller radius than Earth • No clue 10 Countdown

28. 32.Earth’s mass and diameter both double – how does you weight change? • ½ as much • 2x as much • ¼ as much • 4x as much • 1/8 as much • 8x as much • Weight stays the same 10 Countdown

29. 33.On a ladder so you’re 2x as far from Earth’s center – how does your weight change? • ½ as much • 2x as much • ¼ as much • 4x as much • 1/8 as much • 8x as much • Weight stays the same 10 Countdown

30. 1A and 3A • Take out HW due yesterday - we still need to finish reviewing a few questions

31. 1A and 3A • Take out HW due yesterday - we still need to finish reviewing a few questions

32. From now until 3 minutes before the bell… • Use this time to WISELY prep for your test. • Need more math practice? • See page 676 #1, 2, 4, 6 • See page 677 #1 & 2 at TOP of page • Investigate any questions you still have from Do Now • Have questions? ASK NOW • Borrow Monster Note key if you still need to finish • Share your 2 websites with peers and use them to prep for test concepts • When there are 3 minutes left – take an exit slip and complete; also please turn in your WHAT THE question sheet completed to the best of your ability!