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Welcome !!. Homework and Next Class. Write short answers using complete sentences to the following questions: What kind of work do you think you might want to do when you finish your education ? Physics is an elective class. Why did you choose to take this subject ?
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Welcome !! Serra High School Physics
Homework and Next Class • Write short answers using complete sentences to the following questions: • What kind of work do you think you might want to do when you finish your education? • Physics is an elective class. Why did you choose to take this subject? • DUE FIRST CLASS NEXT WEEK!! • Take 15 – 30 minutes and skim through the textbook. Get a broad picture of the topics covered in the book. • Next time: • Class requirements/rules/regs • Short video on automotive engineering Serra High School Physics
Today we start a journey. • My hope is that it changes the way that you look at the world. • Fifty years from now, in 2060, you will remember this class! Serra High School Physics
1 Corinthians 13:9-12 • 9 For we know in part, and we prophesy in part.10 But when that which is perfect is come, then that which is in part shall be done away.11 When I was a child, I spake as a child, I understood as a child, I thought as a child: but when I became a man, I put away childish things.12 For now we see through a glass, darkly, but then face to face: now I know in part; but then shall I know even as also I am known. Serra High School Physics
The Hubble Space Telescope Sky & Telescope, June 2010, p. 21 Serra High School Physics
Stellar Formation Astronomy, September 2010, p. 29 Serra High School Physics
Discovery of New Planets Sky & Telescope, June 2010, p. 25 Serra High School Physics
But we aren’t the first to wonder at the heavens!! Serra High School Physics
University of Tennessee, Knoxville: Astronomy 161 http://csep10.phys.utk.edu/astr161/lect/retrograde/aristotle.html Serra High School Physics
But there were problems…. • The term “planet” was chosen because it means “wanderer.” • Careful observers noted something bizarre….. Serra High School Physics
Retrograde Motion! Sky & Telescope, July 2010, p. 61 Serra High School Physics
Going around in circles… University of Tennessee, Knoxville: Astronomy 161 http://csep10.phys.utk.edu/astr161/lect/retrograde/aristotle.html Serra High School Physics
But there were still problems… University of Tennessee, Knoxville: Astronomy 161 http://csep10.phys.utk.edu/astr161/lect/retrograde/aristotle.html Serra High School Physics
Copernican Model - 1543 University of Tennessee, Knoxville: Astronomy 161 http://csep10.phys.utk.edu/astr161/lect/retrograde/copernican.html Serra High School Physics
A New Explanationof Retrograde Motion University of Tennessee, Knoxville: Astronomy 161 http://csep10.phys.utk.edu/astr161/lect/retrograde/copernican.html Serra High School Physics
Tycho Brahe (1546 – 1601) • Made very precise measurements of planetary positions in the night sky. • There were still problems with the Copernican model!!! • “There is a common misconception that the Copernican model did away with the need for epicycles. This is not true … Copernicus was able to rid himself of the long-held notion that the Earth was the center of the Solar system, but he did not question the assumption of uniform circular motion.” University of Tennessee, Knoxville: Astronomy 161 http://csep10.phys.utk.edu/astr161/lect/retrograde/copernican.html http://csep10.phys.utk.edu/astr161/lect/history/brahe.html Serra High School Physics
Johannes Kepler (1571-1630) • Kepler, a mathematician, was Brahe’s assistant • Doing all calculations by hand, he tried for years to fit the data to circular orbits. • It didn’t work. • He knew the data was accurate so he finally tried elliptical orbits. • After much additional toil - Eureka! University of Tennessee, Knoxville: Astronomy 161 http://csep10.phys.utk.edu/astr161/lect/history/kepler.html Serra High School Physics
Elliptical Orbit • Slightly flattened circle • a + b = constant • Sun is at one of the foci. University of Tennessee, Knoxville: Astronomy 161 http://csep10.phys.utk.edu/astr161/lect/history/kepler.html Serra High School Physics
Kepler’s 1st Law University of Tennessee, Knoxville: Astronomy 161 http://csep10.phys.utk.edu/astr161/lect/history/kepler.html Serra High School Physics
Kepler’s 2nd Law University of Tennessee, Knoxville: Astronomy 161 http://csep10.phys.utk.edu/astr161/lect/history/kepler.html Serra High School Physics
Kepler’s 3rd Law University of Tennessee, Knoxville: Astronomy 161 http://csep10.phys.utk.edu/astr161/lect/history/kepler.html Serra High School Physics
Sir Isaac Newton - (1642-1727) Alexander Pope wrote: Nature and Nature's laws lay hid in night; God said, Let Newton be! and all was light University of Tennessee, Knoxville: Astronomy 161 http://csep10.phys.utk.edu/astr161/lect/history/newton.html Serra High School Physics
Newton’s Second Law of Motion: F = ma or a = F/m • Newton’s Law of Universal Gravitation: University of Tennessee, Knoxville: Astronomy 161 http://csep10.phys.utk.edu/astr161/lect/history/newtongrav.html Serra High School Physics
The Clockwork Universe • Given the laws of motion, if you knew the initial position and velocity of every particle, their future paths could be computed (e.g., this is how we know precisely when a spacecraft will arrive at Pluto). • The future is completely predetermined!!?? Serra High School Physics
There were some amazing triumphs… Mario Livio, Is God a Mathematician?, p. 223 Serra High School Physics
and some amazing applications… Mario Livio, Is God a Mathematician?, p. 222 - 223 Serra High School Physics
But there were still problems… • Einstein eventually overthrew Newton’s ideas of gravity – curved space-time?!?!? • Bizarre behavior was discovered at the subatomic level – “particles” jumping from one place to another without crossing the intervening space?!?!? • Try as they might, there were “simple” mechanical problems that physicists could not solve, i.e., three bodies orbiting each other. Serra High School Physics
CHAOS!!!! • In the 20th century, the clockwork universe fell apart! • A video of Steven Strogatz from Cornell http://www.youtube.com/watch?v=anwl6OZ1UuQ&feature=related Serra High School Physics
What does the bug making waves below while hopping across a pond have to do with the expansion of the universe and the greatest mistake that Albert Einstein ever made? Serra High School Physics
Welcome to our world! That is a story for another day… The universe is a strange and fascinating place. If you understand physics, you will literally be able to “see the universe in a grain of sand” and drawing astonishing connections between seemingly unrelated observations. Consider tuning out the distractions of everyday life - look at the heavens and earth closely and THINK! Serra High School Physics
Homework and Next Class • Write short answers using complete sentences to the following questions: • What kind of work do you think you might want to do when you finish your education? • Physics is an elective class. Why did you choose to take this subject? • DUE FIRST CLASS NEXT WEEK!! • Take 15 – 30 minutes and skim through the textbook. Get a broad picture of the topics covered in the book. • Next time: • Class requirements/rules/regs • Short video on automotive engineering Serra High School Physics