1. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 1 Big Bang, Black Holes, No Math ASTR/PHYS 109 Dr. David Toback Lecture 9, 10 & 11

2. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 2 Was Due for Today – L9 Reading: –(BBBHNM Unit 2) Pre-Lecture Reading Questions: –Unit 1 Revision (if needed): Stage 1 was due before class –Unit 2 Revision (if desired): Stage 1 was due before class Let us know if you were misgraded End-of-Chapter Quizzes: –Chapter 6 Paper 1: –Was NOT assigned last week. Will be due Monday before class in CPR –Can submit a draft for feedback on eCampus if you like before Thursday at 11:55PM Will do our best for late submissions

3. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 3 Was Due for Today – L10 Reading: –(BBBHNM Unit 2) Pre-Lecture Reading Questions: –Unit 1 Revision (if needed): Stage 2 due before class –Unit 2 Revision (if desired): Stage 2 due before class Let us know if you were misgraded End-of-Chapter Quizzes: –Chapter 6 Paper 1: –Stage 1 due Monday before class in CPR –Can submit a draft for feedback on eCampus if you like before Thursday at 11:55PM Will do our best for late submissions

4. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 4 Was Due for Today – L11 Reading: –(BBBHNM Unit 2) Pre-Lecture Reading Questions: –Let us know if you were misgraded End-of-Chapter Quizzes: –(Chapter 6) Paper 1: –Stage 1 was due before class in CPR and turnitin Honors Paper: –Stage 0 due today

5. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 5 Taken from CPR for Paper 1

6. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Paper 1 What is the evidence for Dark Matter? This will be the topic of Paper 1 In order to understand the evidence, we next talk about Dark Matter Will be due 1 week after we finish Chapter 6 6

7. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Papers in CPR/Schedule Schedule is Like PLRQ since it is in CPR: Each Paper has 4 (or 6) Steps: 1.Mentioned after we start the chapter (just did that) 2.Assigned after we finish the chapter 3.Submit text 1 week later (Stage 1) 4.Calibrations/Reviews/Self-Assessment due the week after that (Stage 2) 5.Revision (optional): Stage 1 due one week later 6.If you did a Stage 1, Calibrations/Reviews/Self- Assessment due one week after that 7

8. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Style of the Paper Explain it to someone who isn’t taking the class (no jargon) ~600 words (This is the equivalent of both side of a sheet of paper, double spaced) No citations! Use your own words Text should be professional. You are “trusted guide” not a “buddy” or “comedian” 8

9. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Paper Format Must follow expected Format Usually 5 paragraphs. Needs: –Introduction paragraph –1 paragraph per piece of evidence (3 total?) –Conclusion paragraph that ties it together –http://faculty.physics.tamu.edu/tobac k/109/WritingAssignments/samplepaper.shtmlhttp://faculty.physics.tamu.edu/tobac k/109/WritingAssignments/samplepaper.shtml 9

10. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Help Available for Stage I Submit a draft for feedback from the TA –Submit on eCampus in “Rough Drafts (Optional)” –Drafts due Thursday at 11:55PM –If you submit late, we can try to give feedback but we can’t guarantee it We also recommend going to the writing center 10

11. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Biggest reason people don’t do well 1.Read ALL the instructions on CPR –See the FAQ on papers 2.Don’t forget to submit to turnitin.com 11

12. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Best Guess Schedule Paper 1: Text due 10/5 (Ch 6) Paper 2: Text due 10/12 (Ch 8) Paper 3: Text due 11/06 (Ch 12) Paper 4: Text due 11/11 (Ch 17) Honors Stage 0 (not in CPR): Due 10/5 12

13. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 13 So Far Topics 1.Light and Doppler Shifts  Done 2.Gravity, General Relativity and Dark Matter  Done 3.Atomic Physics and Quantum Mechanics  Now 4.Nuclear Physics and Chemistry 5.Temperature and Thermal Equilibrium

14. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 14 Where We Are Going Next In Chapter 3 we learned a little about how the stuff of the Universe is put together Big things are made from LOTS of small things Small things: The Fundamental Building Blocks of Nature –What is the “stuff” in atoms?

15. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 15 The Largest Stuff Most of the light we see from space comes from stars What are stars made of? –Stars are lots of atoms interacting –The ways they interact creates light we can see –Can study the distant stars by looking at the light from them –Can study atoms here on Earth. Are they the same?

16. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 16 How do Atoms work? ElectroMagnetism (electric charge) –What holds electrons and protons together Quantum Mechanics –The funny way atoms form –Electrons in orbits –Atoms absorbing and emitting photons (light) Chapter 7

17. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 17 Chapter 8 Different Types of Atoms The Strong Force –Keeps protons and neutrons together in the atomic nucleus –Different types of nuclei  different types of atoms –Different atoms  Different light… Nuclear Physics and Chemistry Studying the Stars using their light –Spectral lines of the atoms –Atomic “fingerprints” –The light we see from the stars

18. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 18 Overview of the story Big things are made from LOTS of small things Small things: The Fundamental Building Blocks of Nature –What is the “stuff” in atoms ElectroMagnetism (electric charge) –What holds electrons and protons together Quantum Mechanics –Why atoms form the way they do –Electron in orbits –Atoms absorbing and emitting photons (light) The Strong Force –Keeps protons and neutrons together –Different types of nuclei  different types of atoms –Different atoms  Different light… Nuclear Physics and Chemistry Different TYPES of Atoms Studying the Stars using their light –Spectral lines of the atoms –Atomic “fingerprints” –The light we see from the stars This Lecture Next Lecture

19. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 19 The Fundamental Building Blocks Our best understanding: The very BIG stuff is made up of LOTS of very small stuff Need to understand: 1.What are the fundamental building blocks of nature 2.How it’s all held together 3.How they “create” the light we see

20. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 20 The experiment gives results like #2! Early evidence for the Atomic Model Shoot atoms at a “target” Bag stuffed with cotton and a few small rocks The positive charge in an atom and most of its mass is concentrated in a tiny, very dense center: The Nucleus Bag stuffed with cotton Theory: 1? 2? Experiment (1910’s):

21. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 21 The Building Blocks of Nature In the 19-teens and 20’s experiments determined: Atoms are made of a nucleus surrounded by electrons –Many types of nuclei –Only one kind of electron

22. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 22 Nuclear Physics Many years later (using many of the same methods): Nucleus is composed of neutrons and protons Number of protons and neutrons in the nucleus determines the atom type

23. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 23 The Fundamental Building Blocks of Nature Electrons Neutrons Protons –Neutrons and Protons are really made of quarks Discovered in the 1970’s We’ll talk more about this in the next chapter Talked about this in Chapter 3 More in Chapter 8

24. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 24 Putting Them Together How do we put these fundamental building blocks together to form atoms?

25. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 25 Overview of the story Big things are made from LOTS of small things Small things: The Fundamental Building Blocks of Nature –What is the “stuff” in atoms ElectroMagnetism (electric charge) –What holds electrons and protons together Quantum Mechanics –Why atoms form the way they do –Electron in orbits –Atoms absorbing and emitting photons (light) The Strong Force –Keeping protons and neutrons together –Different kinds of nuclei Nuclear Physics and Chemistry  different atoms Spectral lines of the atoms –Atomic “fingerprints” –The light we see from the stars This Lecture Next Lecture

26. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 26 ElectroMagnetism You probably already know that protons and electrons have “electric” charges Positive charge and negative charge attract each other Call this ElectroMagnetism + -

27. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 27 Weirdness… You probably never thought about it this way but in many ways the way things with electric charge attract is the same as in gravity + -

28. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 28 Gravity vs. ElectroMagnetism ElectroMagnetism Every charged object in the universe “attracts” every other charged object in the universe The bigger the charge, the bigger the attraction The further the distance between the objects, the smaller the attraction Physics 202 Physics 208 Gravity Every object in the universe attracts every other object in the universe The bigger the mass, the bigger the attraction The further the distance between the objects, the smaller the attraction Physics 201 Physics 218

29. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 29 Gravity: –All objects attract no matter what –(As far as we know…) ElectroMagnetism: –Ignores neutral particles What’s different?

30. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 30 Other Differences ElectroMagnetism is MUCH stronger than gravity If I have two electrons, the electric force between them is so powerful that it is 10 42 times stronger than gravity –Can “ignore” gravity inside atoms

31. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 31 Aside ElectroMagnetism is MUCH weaker than the Strong Force For two quarks inside a proton the Strong Force is ~100 times stronger than the EM force –Can almost “ignore” EM inside protons

32. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 32 Atomic Physics How do we make up atoms? 1.Start with a simple (partially wrong) atomic model –Positive Nucleus attracts the negatively charged electrons and keeps them in “orbit” 2.Then move to the weird world of Quantum Mechanics

33. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 33 A Hydrogen Atom The simplest atom: Hydrogen One electron and one proton (Partially wrong) + - | ~10 -10 m | | ~10 -15 m Figure not to scale

34. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 34 Is the world this simple? This is a nice simple model Why does the electron stay in “orbit”? Simple (partially wrong) answer: There is a “Force” that keeps it in orbit just like Gravity keeps the Earth orbiting the Sun

35. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 35 Problem Electromagnetism says electrons slow down when they move in circles Observe this for electrons moving in big circles Should be true for electrons in small circles (atoms) also  Spiral down until they hit the nucleus and we’d have nothing: No atoms! –Would take ~10 picoseconds (10 -11 s)

36. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 36 Another Problem Stars can be in orbit any distance from the center of the galaxy –Depends only on their speed Electrons should, depending on their speed, be able to be almost anywhere near the nucleus (like a planet or a comet) Don’t observe this… Only specific distances from the nucleus

37. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 37 Overview of the story Big things are made from LOTS of small things Small things: The Fundamental Building Blocks of Nature –What is the “stuff” in atoms ElectroMagnetism (electric charge) –What holds electrons and protons together Quantum Mechanics –Why atoms form the way they do –Electron in orbits –Atoms absorbing and emitting photons (light) Different TYPES of Atoms –The Strong Force –Keeping protons and neutrons together (atomic nuclei) –Nuclear Physics and Chemistry –Different atoms  Different light… Studying the Stars using their light –Spectral lines of the atoms –Atomic “fingerprints” –The light we see from the stars This Lecture Next Lecture

38. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 38 Quantum Mechanics How do we explain these weird features that we observe about Atoms? Quantum Mechanics! LOTS we COULD say about QM, but since we could spend years on this we’ll focus only on the most important points you need

39. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 39 Quantum Mechanics Two big issues: 1.All particles can be described both as particles AND waves –Saw this for photons –True for electrons (and protons etc.) also! 2.In atoms: Electrons can ONLY be in one of the available energy states, and at certain distances from the nucleus –Keep atoms from collapsing! (Good!) –“Quantizes” the interactions with light i.e. only some energy photons interact with atoms

40. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Energy of Electron Waves Small energy electron have large wavelengths Small wavelength electrons have large energy 40

41. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 41 Only Orbits with Specific Wavelengths Work The electron “wave” has to go all the way around Can have one peak/trough, two peaks/troughs, three peaks/troughs etc… –A quantized number –The Quantum in Quantum Mechanics

42. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 42 Only Orbits with Specific Wavelengths Work Lower Energy and closer to the nucleus Higher Energy and further away from the nucleus

43. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 43 Energy and Distance from The Nucleus Higher Energy and further away from the nucleus Lower Energy and closer to the nucleus Only these levels are allowed!

44. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 44 How Photons Interact with an Atom To understand better how photons interact with the stuff in an atom, “how we’ll SEE atoms”, we need to say a bit more about Energy and about Quantum Mechanics Lots of different ways they can interact… start with the simple interactions

45. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 45 Simple: Photon-Atom Collision Before: Start with a high energy photon and a low energy atom After: Lower energy photon, higher energy atom (like two billiard balls colliding) Same TOTAL energy before and after collision –Conservation of Energy

46. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Clicker Question After a collision with a stationary atom, the energy of a photon is a)Higher b)Lower c)Same

47. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 47 Clicker Question After a collision with a stationary atom, the speed of a photon is a)Higher b)Lower c)Same

48. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 48 Clicker Question After a collision with a stationary atom, the wavelength of a photon is a)Longer b)Shorter c)Same

49. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 49 Atom-Photon Perspective Photon’s perspective: I collide with a low energy atom and “transfer” some of my energy Atom’s perspective: A high energy photon collides with me and I “take” some of its energy

50. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 50 Quantum Mechanics and EM In General Relativity we found that it is better to describe the “force” of gravity as the curvature of space-time How do we “better” describe ElectroMagnetism, especially with Quantum Mechanics? –Electric fields Answer: In ElectroMagnetism “Force” is essentially all about the “emission” and “absorption” of photons by charged particles like electrons and protons

51. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 51 Quantum Mechanics – Force Carriers Think of the force between electrically charged things as being caused by the exchange of “virtual” photons The force, or interaction, is “carried” by particles

52. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 52 Example with Two Electrons First electron emits a “force-carrying” particle (a photon) Causes a recoil of the first electron –You shoot a gun and lurch back The other electron “catches” it and gets “banged” –Your friend gets hit with the bullet and falls backward Net result: The two particles move differently, “as if” there were a force between them

53. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 53 Visualizing Our Analogy - - 2: electron on the right “emits” a photon and “recoils” 3: Photon bangs into the left electron and bumps it Both now move apart: Same sign charges “repel” each other 1: Two electrons hanging out and then let go

54. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 54 A Proton and Electron -+ 2: Proton on the right “emits” a photon and “recoils” 3: Photon bangs into the electron Doesn’t transfer Momentum Transfers information on how to move Opposite signs attract For those of you who know a little bit, this is how “electric fields” work 1: A proton and an electron hanging out

55. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math More Interactions Can also get electrons and protons interacting with REAL photons –Photons we can see, as opposed to ones that are emitted then absorbed never to be seen outside the interaction Real photons can be emitted or absorbed 55

56. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Electron and Photon Interacting 56 - Electron can “absorb” a photon  Electron becomes more energetic

57. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Electron Emitting a Photon 57 - Electron can “emit” a photon  Electron becomes less energetic

58. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 58 A Simple way of drawing things: Feynman Diagrams Electron can “absorb” a photon  becomes more energetic e e  Electron can “emit” a photon  becomes less energetic e e 

59. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 59 Feynman Diagram for an Atom A diagram of how the particles “talk” to each other These two are attracted Hydrogen Atom  e-e- P P e-e-

60. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math If a photon with the right energy hits an atom and is absorbed, the electron can “jump” to an “excited state” 60 Photon and Atom

61. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math If an atom is in an excited state, it’s just a matter of time before it emits a photon with exactly the energy between the two states 61 Excited Atom Emits a Photon

62. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 62 Other ways of drawing the same thing An electron can move into a more energetic orbit when it absorbs a real photon with exactly the right energy The photon is absorbed, and the electron goes into an excited state A high energy atom can “emit” a photon and go into a lower energy state

63. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 63 A Proton bumps into an atom and excites it Atom in Lowest Energy State Proton Atom in a Higher Energy State

64. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 64 An Excited Atom Emits a Photon Photon with a specific energy Atom in a high Energy State Atom in Lowest State

65. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 65 Absorbing and Emitting a Photon http://bigbang.physics.tamu.edu/Figures/StolenAnimations/bohr.swf

66. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 66 Lots of Different Energy States http://bigbang.physics.tamu.edu/Figures/StolenAnimations/BohrAtom.avi

67. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 67 Photons and Atoms Photons can interact with Atoms in three ways 1.Very low energy photon: Because the electron in the atoms can only have quantized states around the nucleus VERY low energy photons will be ignored, or bump the path of the atom –Ignoring is a kind of interaction 2.If an atom encounters a photon with the “right energy” photon it can get “excited” and go into a higher energy state. Photon is absorbed and is gone forever 3.If a REALLY energetic photon comes along it can completely knock an electron out of orbit from a nucleus

68. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 68 Putting it All Together A cartoon of an atom and a photon Note: The electron being completely out of the atom is a perfectly good “energy state”

69. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 69 Atomic Transitions Any photon that hits the atom with the right energy will be absorbed Absorbs only special colors

70. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math How is this helpful? 70 Can look at light from a light bulb  all colors observed Look at light from a light bulb with Hydrogen gas in the way –Only special colors will be absorbed! Atomic Fingerprinting

71. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 71 Outline for Unit 2: Physics We Need 1.Light and Doppler Shifts  Done 2.Gravity, General Relativity and Dark Matter  Done 3.Atomic Physics and Quantum Mechanics  Done 4.Nuclear Physics and Chemistry  Next 5.Temperature and Thermal Equilibrium

72. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 72 Prep For Next Time – L9 Reading: –(BBBHNM Unit 2) Pre-Lecture Reading Questions: –Let us know if you have been misgraded –Unit 1 Revision (if needed): Stage 2 is due before class –Unit 2 Revision (if desired): Stage 2 was due before class End-of-Chapter Quizzes: –If we finished Chapter 7 then End-of-Chapter Quiz 7a & 7b (else, just through Chapter 6) Paper 1: –Stage 1 due next Monday before class in CPR and turnitin on eCampus –Can submit a draft for feedback on eCampus if you like before Thursday at 11:55PM Will do our best for late submissions Honors Paper: –Stage 0 due October 5 th before class

73. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 73 Prep For Next Time – L10 Reading: –(BBBHNM Unit 2) Pre-Lecture Reading Questions: –Let us know if you have been misgraded End-of-Chapter Quizzes: –If we finished Chapter 7 then End-of-Chapter Quiz 7a & 7b (else, just through Chapter 6) Paper 1: –Stage 1 due Monday before class in CPR and turnitin on eCampus –Can submit a draft for feedback on eCampus if you like before Thursday at 11:55PM Will do our best for late submissions Honors Paper: –Stage 0 due October 5 th before class

74. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 74 Prep For Next Time – L11 Reading: –(BBBHNM Unit 2) Pre-Lecture Reading Questions: –Let us know if you have been misgraded End-of-Chapter Quizzes: –If we finished Chapter 7 then End-of- Chapter Quiz 7a & 7b (else, just through Chapter 6) Paper 1: –Stage 2 due Monday before class in CPR Honors Paper: –Stage 1 due October 19 th before class

75. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Full set of Readings So Far Required: –BBBHNM: Chap 1-9 Recommended: –BHOT: Chap. 1-6, 9 and 11 (117-122) –SHU: Chap. 1-3, 6 and 7 (up- to page 153) –TOE: Chap. 1 75

76. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 76

77. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 77 Clicker Quiz Which of the following travels the fastest? A.Radio waves B.Gamma rays C.Red light D.Blue light E.They all move at the same speed

78. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Clicker Quiz We observe two objects in space. From other studies, we can tell that object X is emitting infrared light and the object Y is emitting Ultraviolet light. We observe the color of the light object X to be Red and the color of Object Y to be blue. Which statement is true? a)X and Y are moving towards us b)X and Y are moving away from us c)X is moving towards us and Y is moving away from us d)X is moving away from us and Y is moving towards us 78

79. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Clicker Question What would happen if you were shot by a gun that fires "dark matter” bullets which have the same volume and mass as a regular bullet? a)Your molecules would significantly spread out from an expansion of space-time b)A black hole would form inside you c)Objects behind you would undergo significant gravitational lensing d)Your body would barely notice e)You would die like you would if you got shot with any kind of bullet 79

80. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Clicker Question Why is dark matter "dark“? a)Because it is closely linked to dark energy b)Because it has no mass c)Because it is made of black holes d)Because it doesn’t interact with light 80

81. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Clicker Question As far as we know, Dark Matter exists: a)Everywhere in the universe b)Only near black holes c)Mostly in or around galaxies d)It doesn't exist e)We don't know where it exists 81

82. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Clicker Question A man shoots a red photon straight up into the air next to a very tall building. The photon rises in the air. Which statements are true: a)The photon slows down as it rises, the same way a rock would b)The photon loses energy, the same way a rock would c)The photon gets blue-shifted 82

83. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Clicker Question What would happen to the Einstein ring around a galaxy who's Dark Matter suddenly wasn't there? a)Nothing b)It would get smaller c)It would get bigger d)It would disappear e)None of the above 83

84. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Clicker Question Instead of throwing a rock into the air, a man shoots a red photon straight up into the air next to a very tall building. The following question are about the photon when it reaches the top of the building. Which of the following statements are true Question 1: Speed a)The speed of the photon stays the same b)The speed of the photon slows down like a rock would Question 2: Energy a)The energy of the photon stays the same b)The energy of the photon gets lower (like the kinetic energy would for a rock) c)The energy of the photon gets larger (since it is getting closer to outer space) Question 3: Color a)The color of the photon stays the same b)The color of the photon is red-shifted (gets a longer wavelength) c)The color of the photon is blue-shifted (gets a shorter wavelength) 84

85. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Clicker Question A hydrogen atom is hit by a photon and the electron absorbs the photon and moves to an excited state. Later, a photon with the exact same energy is emitted from the atom, and the electron moves back to its original state. Is this the same photon as before? a)Yes, it was inside the electron b)Yes, it was bouncing around inside the atom c)No, the electron destroyed the original photon and created the new photon d)No, the nucleus destroyed the original photon and created the new photon 85

86. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Paper 1 Stuff Paper 1 is Pass/Fail –Grade now posted on eLearning May change as we do re-grades –Reasons you might have failed: Overall grade was low Calibrations were low Self-assessment was low Didn’t turn in on time –Need an extension? Tell me IN ADVANCE –Will assess late penalties for late papers You need a passing grade to pass the course 86

87. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Paper 1 Stuff Continued Check if you are grading fairly: –Count the number of no’s in your Rubric. 5 no’s? Can’t be a “great paper” and receive a 9. Were you misgraded? –Send us an email ASAP and we’ll look Need to revise to get a passing grade? –CPR Revision now open –Same procedure, but grading will emphasize your paper –Text due Monday before class –Calibration the following Monday –Need help? Send us an email Paper 2: due 1 week after we finish Chapter 8 87

88. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 88 More Quantum Weirdness Electron can “absorb” a photon  becomes more energetic e e  Electron can “emit” a photon  becomes less energetic e e 

89. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 89 Prep For Next Time – L9 Reading: –(BBBHNM Unit 2) Pre-Lecture Reading Questions: –Let us know if you have been misgraded –Unit 1 Revision: New grades posted soon. –Unit 2 Revision (if desired): Stage 2 End-of-Chapter Quizzes: –Chapter 6 Paper 1: –Stage 1 due Monday before class –Can submit a draft for feedback on eCampus if you like –MUST submit to turnitin on eCampus

90. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 90 Was Due for Today – L10 Reading: –(BBBHNM Unit 2) Pre-Lecture Reading Questions: –Let us know if you have been misgraded –Unit 1 Revision: New grades posted soon. –Unit 2 Revision (if desired): Stage 2 End-of-Chapter Quizzes: –Chapter 6 Paper 1: –Stage 1 due Monday before class –Can submit a draft for feedback on eCampus if you like –MUST submit to turnitin on eCampus

91. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 91 Prep For Next Time – L11 Reading: –(BBBHNM Unit 2) Pre-Lecture Reading Questions: –Let us know if you have been misgraded –Will post Unit 1 Revision grades soon End-of-Chapter Quizzes: –If we finished Chapter 7 then End-of-Chapter Quiz 7a & 7b (else, just through Chapter 6) Paper 1: –Stage 1 due Monday before class –MUST submit to turnitin on eCampus Honors Paper: –Stage 0 due today –Stage 1 due March 11

92. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 92 Was Due for Today – L11 Reading: –(BBBHNM Unit 2) Pre-Lecture Reading Questions: –Let us know if you have been misgraded –Unit 1 Revision: Grades posted soon (still doing regrades) –Unit 2 Revision (if desired): Stage 2 End-of-Chapter Quizzes: –Chapter 6 Paper 1: –Stage 1 due Monday before class –MUST submit to turnitin on eCampus Honors Paper: –Stage 0 due today

93. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 93 Was Due for Today – L12 Reading: –(BBBHNM Unit 2) Pre-Lecture Reading Questions: –Let us know if you have been misgraded –Unit 1 Revision: Grades posted Email sent about how to pass if you haven’t passed already End-of-Chapter Quizzes: –Chapter 6 Paper 1: –Stage 1 in CPR and turnitin on eCampus Honors Paper: –Stage 1 due March 11th

94. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 94 Summary: Atoms vs. Planets Quantum Mechanical effects only the very small (atoms) Electron orbits around a nucleus: Quantized “radii” Planets around the Sun: Not Quantized (too big)

95. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Aside: Actually true for the Earth also. However, it would take 10 24 years (a Quadrillion years, or a yotta-year) to spiral down into the Sun. That’s a billion times the lifetime of the universe 95

96. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 96 Atomic Transitions Wrong energy What happens if a photon doesn’t have the exact right energy to excite an atom it meets? Passes the atom unabsorbed Note… knocking the electron completely out of the atom is a perfectly good “excited state”

97. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 97 Special Photon Energies Atoms only “absorb” or “emit” Special wavelength photons Can only go from one state to another –Only specific colors absorbed –Only photons with specific energy can come out

98. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 98 Analogy Think about Asteroids (or other space junk) banging into the Earth Small piece of junk: Not much happens Big asteroid: Wipes out the dinosaurs REALLY BIG Asteroid: Knocks the Earth out of orbit and off into space (this would be bad)

99. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 99 Aside Smaller: As far as we know all protons (and neutrons) are identical Each particle has an anti-particle –More on this stuff later Bigger: How atoms combine to form molecules and how molecules interact is really chemistry –Won’t spend too much time on this

100. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 100 Other Questions What are stars made of? What can we learn from looking at them? How do we know? Need to know about the stuff out there and how it interacts to create the light we see on Earth

101. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 101 Big Picture: Looking at the Heavens What we know about the universe comes from multiple places Already earned about the light coming from the heavens Need to know more about WHAT PRODUCES the light we observe

102. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 102 Only Orbits with Specific Wavelengths Work The electron “wave” has to go all the way around Can “wave” once, twice, three times etc… –A quantized number

103. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 103 Only Orbits with Specific Wavelengths Work Lower Energy and closer to the nucleus Higher Energy and further away from the nucleus

104. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math Paper Stuff Paper 1 now in progress –The calibration and review portions are due by Wed Feb 24 th, BEFORE class Paper 2 will be due 1 week after we finish Chapter 8 –Tentatively, due March 8 th 104

105. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 105 What Do we Need to Know? When we look at the heavens, we want an answer to the question “what IS all that stuff made of?” Going Further: What is all the stuff that the “stuff” is made of? What’s the evidence for all this?

106. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 106 In-Class Writing Assignment Write down, during the course of lecture, Two questions you want to know the answer to

107. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 107 Papers for the Course There will be three papers for the course –http://faculty.physics.tamu.edu/ toback/109/WritingAssignments/http://faculty.physics.tamu.edu/ toback/109/WritingAssignments/ Due dates are posted there Paper 1 will be assigned after we start Chapter 9, due one week after we finish Chapter 9

108. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 108 In Class Quiz Answer the following question: Tell why the subject of “light” is SO IMPORTANT that we spent an entire on it Make sure to include what we learned that was so important (AND WHY!!)

109. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 109 Does this make sense? Most objects we know and love (the Earth, us etc.) have LOTS of electrons and protons If EM is so much stronger than Gravity why don’t we feel it? Why doesn’t the Earth feel the electric charge of the electrons and protons in the Sun?

110. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 110 EM vs. Gravity Answer: Equal numbers of protons and electrons –Each atom/molecule is exactly electrically neutral or they would attract more charge to make them so

111. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 111 –Bottom line: Accelerating charges emit photons, and accelerating masses emit gravity “waves.” Can’t explain atoms in your body that “live for years”

112. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 112 What’s different? Gravity: –All objects attract no matter what –(As far as we know…) ElectroMagnetism: –Ignores neutral particles Like charges repel each other Opposite charges attract each other

113. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 113 Only Orbits with Specific Wavelengths Work

114. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 114

115. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 115 This is some text

116. Physics We Need Topic 3: Quantum Mechanics and Atoms Big Bang, Black Holes, No Math 116