Introduction to History of Physics

1. Introduction to History of Physics Lecture 1 About Nature Science and Physics

2. Course Syllabus • This course will focus on the fundamental principles underlying natural phenomena, and on applications of these principles to daily life. • We will also explore the changing roles of science and scientists during the past hundreds of year. • There will be an in-class assignment for each lecture. The topics will be over the lecture given in that lecture. Students must submit their assignment before leaving. • No late assignment will be accepted. • There will be no in-class midterm and final.

3. In the Classroom ... • We have more that 60 people in this classroom!!!! • Please don’t drink and eat, and don’t read other books • Please switch off your cell-phone before you come in • You don’t have to sit in straight back but please don’t fall into sleep • Please don’t talk with your neighbor • Be in time. If you are not able to attend the class, please notice me before the class • Don’t start packing your stuff when the lecture is still going on

4. Outline of course • Mechanical Universe and Laws for Motion • Energy and Thermodynamics • Electromagnetism, wave and Light • Relativity • Atom, nuclear and quantum world • Particle physics (if time allows)

5. Before the normal lecture • No one knows everything. So, neither you nor I have to.

6. "The effort to understand the universe is one of the very few things that lifts human life a little above the level of farce and gives it some of the grace of tragedy."

8. Quotation • The more the universe seems comprehensible, the more it seems pointless. • "With or without religion, good people can behave well and bad people can do evil; but for good people to do evil—that takes religion. “

9. Four Golden Lessons 1．邊幹邊學，不要彷徨。當你開始接受一個新課題或進入一個新的研究領域時，往往會感到迷茫。經常遇到的問題是，我現在對這個領域的研究進展一無所知，或者如果我不詳細瞭解已經開展的各種研究，我怎麼去開展一個工作？實際上不必太彷徨，需要牢記的經驗是：你必須立即開始你的研究工作，在工作過程中掌握你需要的知識。記住：沒有一個人會知道所有的事情，你也不需要！2．勇於創新，敢於挑戰。當你在科學的海洋中遨遊時，一定要敢於到險灘、未知的地方去闖闖。在選題時要去選擇那些最有挑戰性、爭論最多、研究最少、還沒有統一結論的課題，這些問題或領域往往是最有作為的，最容易有突破，最容易出成果。3．忍受寂寞，注重過程。你要學會寬恕自己適當的“浪費”時間。在實際生活中，人們都想知道我選擇的科學問題是否是很重要的或者是最重要的。但是要知道哪個問題是最重要的往往是很困難的，你也永遠都不會知道在歷史上的哪個時刻某一個科學問題將會被攻克。由於你不能肯定哪個科學問題是正確的，那麼你在實驗室或辦公室中忙忙碌碌所化費的絕大多數時間有可能是白白“浪費”了的。但是，在科研生涯中，如果你想創新，那麼你就必須習慣你所“浪費”的大多數時間不是在創新，而是很平靜地在科學知識的海洋中漂流著。這個過程是你必須經歷的過程。4. 掌握歷史，樹立信心。你要學習有關科學史方面的知識，至少要知道你所從事的學科領域的發展歷史。科學史對你的科研工作是很有幫助的，也可以使你感受到你工作的價值，還會增加自豪感。如果你在某個領域或某個科學問題上真的作出了成績，在科學發展史上添了一筆，為人類作出了貢獻，你怎麼會有理由不自豪呢？

10. Etymology of the word “Physics” • Physics comes from the Greek word “Fυσικά,” title of one of Aristotle’s book; it is an adjective meaning everything related to nature (“Fύσις”.) Thus, any type of motion as the solar system evolution, all we can investigate with our senses that is related to nature belongs to the field of Physics.

11. Elements of what became physics • Elements of what became physics were drawn primarily from the fields of astronomy, optics, and mechanics, which were methodologically united through the study of geometry. • These mathematical disciplines began in Antiquity with the Babylonians and with Hellenistic writers such as Archimedes and Ptolemy. • Meanwhile, philosophy, including what was called “physics”, focused on explanatory (rather than descriptive) schemes, largely developed around the Aristotelian idea of the four types of “causes”.

12. Archimedes ( 287 BC – 212 BC) Archimedes is generally considered to be the greatest mathematician of antiquity and one of the greatest of all time. He used the method of exhaustion to calculate the area under the arc of a parabola with the summation of an infinite series, and gave a remarkably accurate approximation of pi. He also defined the spiral bearing his name, formulae for the volumes of surfaces of revolution and an ingenious system for expressing very large numbers.

13. A sphere has 2/3 the volume and surface area of its circumscribing cylinder. A sphere and cylinder were placed on the tomb of Archimedes at his request.

14. Archimedes may have used his principle of buoyancy to determine whether the golden crown was less dense than solid gold.

15. Archimedes may have used mirrors acting collectively as a parabolic reflector to burn ships attacking Syracuse. The Archimedes screw

19. Indulgingin the amazing math skills turn a blind eye to the risk of being uprooted

20. Appetizer The prehistoric origins of science

22. The Hubble Space Telescope "Ultra Deep Field" View

23. The NASA illustration depicts the range of view of some of the galaxies of the ultra-deep field as being in the range of 400 to 700 million years after the big bang, some of the most distant objects ever viewed.

24. Hoag's Object, an example of a ring galaxy.

25. The Antennae Galaxies are undergoing a collision that will result in their eventual merger.

26. Our Milky Way

27. A perspective of the Sun's location in the galaxy. It is based roughly on a sketch by Gonzalez and Richards.

28. Constellations our existence and our self-importance, are related to the way the constellations is formed.

29. Solar System

30. Size comparison of terrestrial planets

31. The Size of the Solar system

32. VY Canis Majoris is at between 1800 to 2100 solar radii. it is the largest known star and also one of the most luminous known.

33. The Ancient Greeks • Science made great headway in Greece in the 7th century BC and spread throughout the Mediterranean world. • Scientific progress came to halt in Europe when the Roman Empire fell in the 5th century AD. • Barbarian hordes destroyed almost everything in their paths as they overran Europe and ushered in the Dark ages.

34. In Contrast to Europe • Chinese show little interest in the concepts of natural philosophy and mathematics, which seemed to them to have no practical applications, even ancient Chinese invented many the state-of-art technologies of that time.

35. 《定情賦》夫何妖女之淑麗， 光華豔而秀容。 斷當時而呈美， 冠朋匹而無雙。 歎曰：「大火流兮草蟲鳴， 繁霜降兮草木零。 秋為期兮時已征， 思美人兮愁屏營。」　 思在面為鉛華兮， 患離塵而無光。

36. Remains of a Chinese crossbow, 2nd century BC.

37. During the Dark ages • The Chinese were charting the stars and the planets. • Arab nations were developing mathematics.

38. Renaissance • The Renaissance was a period of rebirth in the arts and scholarship in Europe as the feudalism of the Middle Ages waned. • Greek science was reintroduced to Europe by Islamic influences that penetrated into Spain during the 10th, 11th and 12th century. • Universities appeared in the 1200s at Paris, Oxford, Naples, and Cambridge, to name a few.

39. What is Science ? Science is the concerted human effort to understand, or to understand better, the history of the natural world and how the natural world works, with observable physical evidence as the basis of that understanding. It is done through observation of natural phenomena, and/or through experimentation that tries to simulate natural processes under controlled conditions.

40. Ibn al-Haytham (Alhacen, 965–1039, a pioneer of scientific method) • The emphasis has been on seeking truth. • Finding the truth is difficult, and the road to it is rough."

41. 『欲誠其意者，先致其知；致知在格物。物格而後知至，知至而後意誠』『欲誠其意者，先致其知；致知在格物。物格而後知至，知至而後意誠』

42. T. D. Lee

43. A few Definitions • fact: a truth known by actual experience or observation • deductive inference: a conclusion based on reasoning from accepted premises • inductive inference: a conclusion based on repeated observation of fact • hypothesis: a proposition explaining the occurrence of a phenomenon or phenomena • theory: a coherent set of propositions that explain a class of phenomena, that are supported by extensive factual evidence, and that may be used for prediction of future observations

44. Five criteria for the evaluation of scientific hypotheses • relevant • testable and falsifiable • consistent • simple • predictive

45. Scientific Method • Recognize a problem • Make an educated guess-a hypothesis • Predict the consequence of the hypothesis • Perform experiments to test predicts • Formulate the simplest general rule that organizes the three main ingredients-hypothesis, prediction, experimental outcome

46. general principle induction deduction observations prediction revision individual events The Scientific Method specific instances  Science is a history of corrected mistakes (Popper)

47. WARNING !! Pitfall language • Daily life:“theory” = an opinion, a conjecture • Science: theory = a hypothesis that is sufficiently accepted and which shows enough explanatory power to be strongly confirmed by experiment. In no case is a scientific hypothesis or theory just a mere guess. • Statements like “It’s just a theory” used to assess the value of a scientific theory are therefore meaningless because they mix-up different usages of the word “theory”.

48. The scientific tool

49. Mathematics-the language of science

50. Bob washed his hand • Function F(t): a mapping • F(t) belongs to set A when t < t0 • F(t) belongs to the complement of the set A when t >= t0