Physics 8A Introductory Physics

Physics 8AIntroductory PhysicsProf. Yury KolomenskySpring 2007

What Do Physicists Do ?(Or what I do when I am not teaching Phys8a) Basic answer: attempt to understand the Lawsof Nature and the Structure of the Universe Sounds grandeur, doesn’t it ? Different scales: space scales, time scales From subatomic particles to the entire visibleUniverseFrom present time to the Big BangFrom “fundamental interactions” to applications01/17/2007YGK, Physics 8A

Ultimate PuzzleHow do these make up all this ?01/17/2007YGK, Physics 8A

Why ? Human curiosity Have you ever stared at the night sky and wonderedwhere it all came from ?Or more importantly, where is it all going ?People have -- for as long as we remember. Don’t just take my word for itQuestion #1: What is the Universemade of ?01/17/2007YGK, Physics 8A

“Spinoffs”: Discoveries Lead toApplications01/17/2007YGK, Physics 8A

Examples Close to My HeartPolarized noble gas target in myPh.D. experimentPolarized noble gas in humanlungs ( U of Virginia)01/17/2007YGK, Physics 8A

So Why Should YOU Learn AnyPhysics ? You will graduate from UC Berkeley eventually We want you to be a well-educated member of societyYou may one day be important But more importantly, you will be using moderntechnology in your professional life You should understand how tools work to use themeffectivelyYou could invent new applicationsAnd you should be confident in your knowledge No black magic ! Even more important: being able to “think like aphysicist”01/17/2007YGK, Physics 8A

Think Like a Physicist01/17/2007YGK, Physics 8A

Think Like a Physicist ? To demonstrate, let’s conduct a quick pollWhat is your favorite medical TV show ?a)b)c)d)e)f)01/17/2007ERGrey’s AnatomyScrubsHouseGeneral HospitalI don’t watch TV, this class is enoughentertainmentYGK, Physics 8A

You May Guess What I’d Pick01/17/2007YGK, Physics 8A

Think Like a Physicist Physics relates observations to a small set offundamental laws Deductive reasoningAbstractionGeneralization Physics laws describe relationships between physicalquantities The number of quantities is finiteSmall number of “fundamental” lawsMore complex relationships are derived from thesefundamental laws, iteratively Solving a problem means finding the rightrelationships, and applying them to the situation01/17/2007YGK, Physics 8A

Solving a Physics Problem The process of solving a “physics problem” isdifferent from biological sciences1.2.3.4.5. Make observation (read the problem)Abstract the process (throw away useless info, makesimplifications, draw a picture)Identify conceptsFind the relationships between knowns and unknowns EquationsSolve for unknowns, plug in the numbersThe key step is #4 01/17/2007Hard to jump there directlyThis is a common “don’t know how to start” issueYGK, Physics 8A

Summary of Mechanics You can’t parse thisyet, but that’s OK 01/17/2007Every symbol here is aconceptEvery line is arelationship (equation)Together, they form a“roadmap”, you canactually use it to solvephysics problems !The key is not tomemorize formulae,but to learn therelationships andconceptsYGK, Physics 8A

Structure of the Course Linear progression Topics are covered in natural succession Two semesters Physics 8A Mechanics Fluid statics and dynamics Waves, Optics Thermal physicsPhysics 8B Electricity and magnetism Relativity Quantum physics01/17/2007YGK, Physics 8A

Introductory Physics: a Survey “Only” 2 semesters Will review most important phenomenaWill generalize observations in a small set offundamental laws Physics is experimental science Avoid memorizing Specific knowledge: phenomena, laws, numbersLearn to apply it: problem solvingAbstract thinking. Concrete applications. Think like a physicist01/17/2007YGK, Physics 8A

Learn By Doing Five important ingredients of the course Book: introduction and referenceLectures: observe (demos), then derive (laws)Discussion sections: name says it all DISCUSS !Labs Experiment !Homeworks ReinforceAnd finally, exams Assess01/17/2007YGK, Physics 8A

How You Should Learn “Spiral Learning” concept 3 states to achieve knowledge1. Ignorance2. Confusion3. Understanding One can argue, that there are several degrees of understanding.Profound understanding, requires belief or reinforcement. Wepromote the latter. So, optimally, your sequence would be1. Read the book2. Attend lecture, take notes, ask questions3. Go to discussion section, ask questions !4. Do homework5. Return to the book to reinforce Rinse and repeat01/17/2007YGK, Physics 8A

Class Organization See website http://moller.physics.berkeley.edu/ phys8a01/17/2007YGK, Physics 8A

GradingFall ‘05F01/17/2007DCBAYGK, Physics 8A

Homeworks are Important01/17/2007YGK, Physics 8A

Extra Curriculum Activities “On the Same Page with Stephen Hawking” Campaign promoted by the College of Letters andSciencesShared intellectual experience: read and discussStephen Hawking’s “Brief History of Time” I would be happy to discuss the book with you (outsideof class) You may want to attend Hawking’s public lecture onMarch 1301/17/2007YGK, Physics 8A

The Dan Brown Challenge Dan Brown’s other book, “Angels andDemons” is very loosely based on physics“facts” Your challenge: find the largest number of physicsfaux pas in this book Any false facts, statements, or situations that are simplyimpossible Numbers that are wrong by more than an order ofmagnitude Whoever gets the largest number of (verifiable) blundersgets a prize from me at the end of the semester (no, it’snot a grade increase :)01/17/2007YGK, Physics 8A

What Would YOULike to Learn ?01/17/2007YGK, Physics 8A

01/17/2007 YGK, Physics 8A Solving a Physics Problem The process of solving a “physics problem” is different from biological sciences 1. Make observation (read the problem) 2. Abstract the process (throw away useless info, make simplifications, draw a picture) 3. Identify concepts 4. Find the relationships between knowns and unknowns .