Today’s special

1. Today’s special • HW check: vocab • Test results • Secret lives of scientists • Notes • HW I due next!!! • Car race: round 4

2. Gravity PAe.5: Explain how acceleration due to gravity affects the velocity of an object as it falls. PAe.10: Explain how the gravitational force between two objects is affected by the mass of each object and the distance between them. PAa.1: Generate hypotheses on the basis of credible, accurate, and relevant sources of scientific information. PAa.2: Use appropriate laboratory apparatuses, technology, and techniques safely and accurately when conducting a scientific investigation. PAa.9: Use appropriate safety procedures when conducting investigations.

3. Before anything else, preparation is the key to success. Alexander Graham Bell Fact: The short phrases of organ music played at a baseball game is called a tucket.

4. Questions: • How does the International Space Station remain in orbit around the Earth? • Why doesn’t it come crashing down to the Earth’s surface? • Are the astronauts “weightless”?

5. Tangential velocity • Velocity parallel to the Earth’s surface • The moon is falling around the Earth, not into it

6. Law of Universal Gravitation • Every mass attracts every other mass, no matter how big or small • The force is proportional to (m1m2)/d2 • Note: “inversely as d is squared”; what happens if the distance is doubled, tripled, etc.

7. Inverse square law • Inverse of KE idea • The decrease proportion is the square of the distance, twice is one fourth; three times is one ninth, four times is…

8. Universal Gravitational Constant • Relates gravitational force with mass and distance

9. Today’s special • HW I check • Q & A • Car race, round 5! • Measure the Earth’s mass • Finish notes • Air drop! (due next time)

10. Measuring the mass of the Earth • Use mass of 1 kg, gravity, the Earth’s radius, and G • r = 6,371 km

11. Tides

12. Big bang

13. Dark Matter • Most of the stuff in clusters of galaxies is invisible and, since these are the largest structures in the Universe held together by gravity, scientists then conclude that most of the matter in the entire Universe is invisible. This invisible stuff is called 'dark matter'. There is currently much ongoing research by scientists attempting to discover exactly what this dark matter is, how much there is, and what effect it may have on the future of the Universe as a whole.

14. Questions: • How does the International Space Station remain in orbit around the Earth? • Why doesn’t it come crashing down to the Earth’s surface? • Are the astronauts “weightless”?

15. HW • Chapter HW: pp. 113-116 • I. Review questions2-20 even (due date: ____________) • II. Exercises 2-20 even; Problems 1-10 (due date: __________)

16. Today’s special • HW I check; Q & A • Lab: Air drop • Car race III • Work time with Exam Review Group presentation partners

17. Today’s special • Turn in Air drop lab on front desk • Notes/practice for HW II • HW II due next time • Work time with Exam Review Group presentation partners • Car race round IV

18. Today’s special • HW II check • Car race Round 7 • Lab: Gravity measuring machine or Air drop • ISS tour • Practice Test 7 • Test next!

19. Today’s special • Test 7 Gravity • Turn in on front desk • Get Vocab 8 Projectile and satellite motion • Car race round 8? • ISS tour • Notes 8

20. Today’s special • Presentation should be saved in file on common drive • Presentations • Take notes/pay attention • Exam review packet • Class work time