1. The Enlightenment and Modern Astronomy

2. Warm Up Questions CPS Questions (1-2) Chapter 1, Lesson 3

3. Lesson Overview  Galileo and the Telescope  Newton’s Laws of Motion and Gravity  Einstein and Relativity Chapter 1, Lesson 3

4. Quick Write Which do you think is more important for real scientific progress – curiosity and imagination, or up-to-date scientific tools? (Note to teacher: Use “Pick a Student” button in CPS) Chapter 1, Lesson 3

5. Galileo and the Telescope  Galileo did not invent the telescope but he was the first person to use a telescope to study the sky © National Library of Medicine

6. Galileo and the Telescope, cont.  Galileo made observations such as  mountains and valleys on the Moon  many more stars than can be observed with the naked eye  These ideas were unsettling to those who believed in “perfection of the heavens” Chapter 1, Lesson 3

7. Jupiter’s Four Moons  Four moons revolved around Jupiter  Io, Europa, Ganymede and Callisto never appear north or south of Jupiter  Suggested to Galileo that their orbital plane aligned with that of Earth  Contradicted the theory that Earth must be stationary or it would lose its Moon Chapter 1, Lesson 3

8. Phases of Venus Venus has phases like those of Earth’s Moon Courtesy Lowell Observatory

9. Phases of Venus, cont.  Venus seems to change size  Arc of Venus’s crescent is much larger than the full Venus, showing that it is significantly closer to Earth  Supports the Sun-centered model Chapter 1, Lesson 3

10. Newton’s Three Laws of Motion  Inertia - the tendency of an object to resist a change in its motion  Newton’s First Law of Motion: A body in motion tends to stay in motion, and a body at rest tends to stay at rest ©Photos.com

11. Chapter 1, Lesson 3 Newton’s Three Laws of Motion, cont. A)The wheeled brick will accelerate B) if a force is exerted on it. C)If twice as much force is exerted on it, it will accelerate at twice the rate. The same amount of force will give twice as much mass only half the acceleration. Newton’s Second Law

12. Newton’s Three Laws of Motion, cont.  Newton’s Second Law: How much force is necessary to produce a certain acceleration of an object  Force = mass x acceleration (F=ma) OR acceleration = Force ÷ mass (a=F/m)  Newton’s Third Law of Motion: For every action there is an equal and opposite reaction Chapter 1, Lesson 3

13. The Law of Gravity  Every object in the universe attracts every other one  The greater the mass of an object, the greater the attractive force it exerts on other objects  On Earth the force of gravity made objects fall to the ground  Gravity also held the Moon in orbit around the Earth, and the planets in their orbits around the Sun Chapter 1, Lesson 3

14. How Newton’s Laws Confirmed Kepler’s  Sun as the source of the force responsible for the motion of the planets  The gravitational force acting on an object orbiting the Sun (or other stationary body) always points toward the Sun  Laws of motion and gravity can be applied to any two objects orbiting each other Chapter 1, Lesson 3

15. Einstein and Relativity  Principle of Equivalence – effects of acceleration are indistinguishable from gravitational effects © AIP Emilio Segrè Visual Archives Chapter 1, Lesson 3

16. Einstein and Relativity  Einstein proposed thinking of space as being curved by a mass – objects move because of the curvature  Three dimensions are needed to describe the position of something  North-South  East-West  Up-Down Chapter 1, Lesson 3

17. Testing the Bending of Light  It takes a very massive object to bend light with gravity in an amount you can detect  During the 1919 eclipse, light from two stars bends and makes the stars appear farther apart

18. Constant Speed of Light Proves the Special Theory of Relativity  No place in the universe is stationary or “at rest”  Light always travels at the same speed regardless of the observer’s speed  Mass (m) can be transformed into energy (E) E=mc2  The first explosion of a nuclear bomb confirmed this equation in 1945 Chapter 1, Lesson 3

19. Learning Check CPS Questions (3-4) Chapter 1, Lesson 3

20. Activity 1: Modern Astronomy Matching Match the term with it’s definition or explanation Chapter 1, Lesson 3

21. Activity 2: Newton’s First Law of Motion 1.Stack the sugar cubes to make a tower. 2.Lay the ruler flat on the table. Swing the ruler sideways quickly so that you only hit the bottom sugar cube. 3.Stack the sugar cubes again. Try removing the sugar cubes one by one without knocking over the tower. Chapter 1, Lesson 3

22. Activity 3: Newton’s Second Law of Motion 1.Tie the string around the outside edge of one eraser. Attach the paper clip to the string on one of the narrow edges of the eraser. Stack the remaining erasers on top of the first eraser. 2.Hook the spring scale to the paper clip and slowly pull the stack of erasers across a table. 3.Remove the top eraser. Pull the remaining two erasers across the table using the same amount of force you used in step 2. 4.Repeat step 3 using just one eraser. Try to use the same amount of force as you did in step 2. Chapter 1, Lesson 3

23. Technology Enrichment: Four Forces Answer the questions on the worksheet after watching the video clip from NASA about the forces in action on an airplane in flight. If you are unable to watch the video, research the answers to the questions on the worksheet about the forces of flight using a search engine, such as google.com or yahoo.com. Chapter 1, Lesson 3

24. ReviewReview  Galileo used the telescope to make observations that informed the debate between heliocentric and geocentric theories  Sir Isaac Newton was the first to create a unified model of how the universe works  Scientists’ much greater understanding of the universe would not have been possible without Einstein Chapter 1, Lesson 3

25. Review Questions CPS Questions (5-6) Chapter 1, Lesson 3

26. SummarySummary  Galileo and the Telescope  Newton’s Laws of Motion and Gravity  Einstein and Relativity Chapter 1, Lesson 3

27. Next…Next…  Done - Enlightenment and Modern Astronomy  Next - Earth: Inside and Out Courtesy of NASA