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Bellwork

Bellwork. Who is credited with the revolutionary model of a HELIOCENTRIC solar system? A. Aristotle B. Ptolemy C. Galileo D. Copernicus The planets loop backwards in their orbits. TRUE FALSE During which months is Earth closest to the Sun?. The story so far….

dennis-mejia
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Bellwork

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  1. Bellwork • Who is credited with the revolutionary model of a HELIOCENTRIC solar system? A. Aristotle B. Ptolemy C. Galileo D. Copernicus • The planets loop backwards in their orbits. • TRUE • FALSE • During which months is Earth closest to the Sun?

  2. The story so far…. • Ancient Greeks had a GEOCENTRIC model of the solar system with Earth in center and Sun and planets in perfect circles. • Ptolemy add many epicycles to explain the looping of planets during retrograde motion. • Galileo used a telescope to see phases of Venus, Jupiter’s moons, rotating sunspots • Copernicus made a HELIOCENTRIC model of the solar system with the Sun in the center so the planets were NOT looping backwards, Earth’s faster orbit was ‘passing’ the slower outer planets.

  3. http://www.classzone.com/books/earth_science/terc/content/investigations/es2603/es2603page01.cfmhttp://www.classzone.com/books/earth_science/terc/content/investigations/es2603/es2603page01.cfm

  4. Kepler’s Model of the Solar System

  5. Tycho Brahe (1575) • After seeing the total eclipse on August 21, 1560, and became a master of careful astronomical OBSERVATIONS. • Lost part of his nose in a duel and replaced it with a metal one. • Made DETAILED naked eye observations of the motions of the planets. • In the course of 30 years, he had amassed the best astronomical DATA of the day

  6. Johannes Kepler’s(1600) Kepler ‘inherited’ the observations after the sudden death of Tycho Math skills - Kelper's skills were extraordinary. He could not get Tycho'svery careful observations to Copernicus model. 3 Laws about planets orbits: SHAPE, SPEED, TIME

  7. Kepler’s 3 Laws of Planetary Motion 1st Law: Ellipses! TheSHAPEof the orbital paths of each planet is an ellipse(NOT a perfect circle) (with the Sun not exactly in the center, but at one focus)

  8. http://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::800::600::/sites/dl/free/007299181x/78778/Kepler_Nav.swf::Keplers%20Second%20Law%20Interactivehttp://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::800::600::/sites/dl/free/007299181x/78778/Kepler_Nav.swf::Keplers%20Second%20Law%20Interactive

  9. 2nd Law: SPEEDof the planet An imaginary line connecting the Sun to any planet sweeps out equal areas in equal time.. Area 1 90 days Area 2 90 days Planets have variations in their orbital speed

  10. Kepler’s 3rd Law: a planet’s orbital TIMEis proportionalto its distance. In other words……the farther away the planet, the longer its ‘year’ P2(years) = A3(AU) 1 Astronomical Unit = The Earth-Sun Distance (93 million miles)

  11. Kepler’s Third Law = = = = = = = = =

  12. Heliocentric Solar System Using data construct a model to show the correct SIZE and SCALE

  13. Isaac Newton (1642 – 1727) • One of the most brilliant theoreticians to ever live. • ExplainedWHY the planets moveas they do. • He formulated three laws of motion and the law of universal gravitation.

  14. Newton’s 1st Law of Inertia:Objects in uniform straight line motion continue in straight line motion unless an outside force is applied to change their motion Once in orbit, a planet will continueits orbital motion at constant velocity until an outside force (asteroid, another planet?) acts on it to change its orbit.

  15. Newton’s Second Law The ACCELERATION (change in motion) of an object is directly proportional to the net FORCE acting on the object, is in the direction of the net force, and is inversely proportional to the MASS of the object. a = Fnet mass WHY OR F = ma

  16. Newton’s Third Law Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object. Forces are interacting in PAIRS – one object on another “To every action there is an equal and opposite re-action.”

  17. Law of Universal Gravitation Mass attracts mass Gravityis the FORCE that causes objects to move!

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