Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 1 Big Bang, Black Holes, No Math ASTR/PHYS 109 Dr. David Toback Lecture.

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 1 Big Bang, Black Holes, No Math ASTR/PHYS 109 Dr. David Toback Lecture 12 & 13

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 2 Was due Today – L13 Reading: –(BBBHNM Unit 2) Pre-Lecture Reading Questions: –Let us know if you were misgraded –Unit 1 in CPR You MUST pass this portion to pass the class Grades on eCampus, Contact me if you haven’t passed yet (additional quizzes needed) End-of-Chapter Quizzes: –Chapter 7a & 7b quizzes Paper 1: –(Stage 2 is due Monday before class) –(Text needs to be in turnitin on eCampus) Honors Paper: –Stage 1 due March 11 th

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math Heads Up: Paper 2 What is the evidence that Stars are made of Atoms? This will be the topic of Paper 2 In order to understand the evidence, we next talk about Atoms and how they work Will be assigned after we finish Chapter 8 3

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 4 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  This time 5.Temperature and Thermal Equilibrium

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 5 Looking at the Lights in the Sky What we know about the universe comes from multiple places So far: Learned about the light coming from the sky Learned that atoms can produce this light

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 6 Questions We’re Trying to Answer What are stars made of? What can we learn from looking at them? How do we know? Today: More about different types of atoms that produce the light  A “smoking gun” piece of evidence that the light from the sky is from atoms out there

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 7 Outline Overview What protons and neutrons are made of: Quarks How protons and neutrons interact & combine to form a nucleus Chemistry Spectral lines –Light from stars! Learning about the stars

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 8 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 Last Lecture This Lecture

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 9 Smaller Building Blocks of Nature Atoms are made of a nucleus surrounded by electrons –Many types of nuclei –Only one kind of electron Nuclei is composed of neutrons and protons –Neutrons and protons are two different types of nucleons Nucleons are made of quarks

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 10 Chemistry We can put nucleons together in lots of different ways… Each different way corresponds to a different type of atom Knew about the periodic table in the 19 th century, understood it was just combinations of protons and neutrons in the 1920’s

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 11 Observation: Different Kinds of Atoms The kind of atom depends on the number of protons in the nucleus Helium 4 Different numbers of neutrons ↔ different isotopes Helium (He), with 2 protons, 2 neutrons and 2 electrons

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 12 Why do nucleons stick together? If what holds the atom together is the opposite charge of the protons and the electrons…  Why don’t the same sign charges of the protons “blow the nucleus apart?”

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 13 What Nucleons are Made Of Each nucleon is made of 3 quarks Two different types of quark Called “up” quarks and “down” quarks Each quark has fractional charge More to say about this later

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 14 What holds the quarks together? The strong force holds the quarks together inside the nucleon The force mediator is the “gluon” –Quarks talk to each other via gluons

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 15 The Answer The same strong force keeps the nucleons together Essentially the gluons “leak” out of the nucleons and provide the attractive force

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math So what? Why do we care about all the different kinds of atoms? What does this have to do with Stars and the Big Bang? The different mass and charge of each nucleus means that each as a different set of energy levels –Each one has unique fingerprints! 16

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 17 Different energy levels for each different type of atom Can use light of different energies to identify atoms: Different Colors Hydrogen Helium Boron Fingerprinting the different atoms

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 18 Atomic Fingerprints Each atom produces a large number of different wavelengths with VERY SPECIFIC values Quantum Mechanics predicts ALL of them If you see all the ones you expect and none you don’t, that gives you confidence

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math More on Fingerprinting 19 Look at light from a light bulb with Hydrogen gas in the way Different lines will be absorbed by Helium Can now identify a mystery gas!

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 20 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 Last Lecture This Lecture

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 21 Using Light From Stars Can look at the light from the stars to “see” if they are made of atoms Figure out what TYPE of atoms… How stars are formed… What makes them shine…

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 22 What is a Star? Our best understanding is that stars are great big balls of (mostly) hydrogen gas The hydrogen interacts and produces the light we see –Makes them shine… What is the evidence for this?

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 23 Stars What would happen inside a giant ball of hydrogen? –Interactions What would it look like to us? –Light from the interactions –Next look at interactions 

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 24 Proton + Proton  Deuterium + Anti-Electron + Neutrino Hydrogen Interactions Proton  Deuterium Nuclear Reaction Anti- Electron Neutrino The Deuterium, neutrino and the Anti- Electron get energy in the reaction

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 25 Proton + Deuterium  Helium 3 + Photon More interactions Deuterium Proton  Helium 3 Nuclear Reaction Photon Photon can have almost any energy

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 26 Helium 3 + Helium 3  Helium 4 + 2 Protons Creating Stable Helium Helium 3 Helium 4 Nuclear Reaction Proton

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 27 Stars Nuclear interactions in the center of the star create lots of energy which is eventually emitted as light from the surface of the star –Shine white (or yellow) This light passes through other atoms of the star –Light is “absorbed” by the outer atoms  Spectral lines Tells us what the stars are made of

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math Looking at the Stars 28

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 29 Analyzing Absorption Spectra Each element produces a specific set of absorption (and emission) lines Using this information, we can study the composition of stars See only spectral lines for known atoms

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 30 Remarkable… The Sun and stars are mostly made of Helium and Hydrogen Our Sun is made of the same stuff as all the other stars! The stuff out in the universe is made of the same stuff that is found here on Earth!

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 31 Even More Remarkable If all the stuff “out there” looks the same as the stuff here on Earth then: –The particles out there (electrons, protons, photons etc.) are the same as they are here –The laws of physics that govern putting together protons, nuclei and atoms are likely to be the same everywhere! –Provides evidence that it’s been this way for billions of years !

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 32 Now that we know what stars are made of and what they are SUPPOSED to look like, can we learn anything else?

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 33 What if the stars were MOVING? Can we tell? Yes! Doppler effect How?

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 34 Atoms with Different Speeds If an atom emits a photon it will correspond to an energy that reflects the change of two energy levels However if the atom is MOVING the light will be shifted to a different color

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 35 Observing an Atom Atom Emitting Light Not MovingMoving to the right Can use this to study the motions of the stars

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math Looking at the Stars 36 Provides additional evidence stars are made of atoms

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math Paper 2 37 Abbreviated description: What is the evidence that Stars are made of Atoms? –More detail on CPR, you REALLY need to read ALL the instructions Explain it to someone who isn’t taking the class (no jargon) Format: –Introduction paragraph –~1 paragraph per piece of evidence –Conclusion paragraph that ties it together –http://faculty.physics.tamu.edu/toback/109/WritingAssignmen ts/samplepaper.shtmlhttp://faculty.physics.tamu.edu/toback/109/WritingAssignmen ts/samplepaper.shtml

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math Phase I and Phase II in CPR Phase I: (Due 1 week after we finish Chapter 8) Submit online two ways: CPR and turnitin.com Phase II: (Due one week after Phase I) Three-Part Calibrations/Reviewing 1.Calibrations, learning to use the Rubrics 2.Grade three other papers 3.Grade your own paper Want feedback before you submit? Get it to the TA on eCampus by Friday for guaranteed feedback. 38

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 39 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  Done 5.Temperature and Thermal Equilibrium  Next time

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 40 Prep for Next Time – L12 Reading: –(BBBHNM Unit 2) Pre-Lecture Reading Questions: –Let us know if you were misgraded –Unit 1 Grades Posted in eCampus, contact if needed End-of-Chapter Quizzes: –If we finished Chapter 8 then end-of-chapter quiz 8 (else just up to Chapter 7a & b) Papers: –Paper 1: Stage 2 is due before class on Monday (Text needs to be in turnitin on eCampus) –Paper 2: If we finished Chapter 8, Stage 1 is due Monday before class Also due in turnitin Honors Paper: –Stage 1 due Wed March 11th

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 41 Prep for Next Time – L13 Reading: –(BBBHNM Unit 2) Pre-Lecture Reading Questions: –Let us know if you were misgraded –Unit 1 Grades Posted in eCampus, contact if needed (more quizzes to take) End-of-Chapter Quizzes: –If we finished Chapter 8 then end-of-chapter quiz 8 (else just up to Chapter 7a & b) Papers: –Paper 1: Stage 2 is due before class on Monday (Text needs to be in turnitin on eCampus) –Paper 2: If we finished Chapter 8, Stage 1 is due Monday before class Also due in turnitin Honors Paper: –Stage 1 due Wed March 11th

Physics We Need Topic 4: Nuclear Physics & Chemistry 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 42

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 43

Physics We Need Topic 4: Nuclear Physics & Chemistry 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 44

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 45 Clicker Question A star is observed with the following light pattern. Which way is it moving? a)Towards us, slow speed b)Away from us, slow speed c)Towards us, high speed d)Away from us, high speed e)Stationary

Physics We Need Topic 4: Nuclear Physics & Chemistry 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 46

Physics We Need Topic 4: Nuclear Physics & Chemistry 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 47

Physics We Need Topic 4: Nuclear Physics & Chemistry 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) 48

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 49 Clicker Question Two mystery galaxies (on the right) only have a single spectral line in the visible spectrum as shown below. If the above galaxy is stationary, which way is the below galaxy moving? a)Towards us b)Away from us c)It is also stationary d)Not enough information

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math Extra Credit Still offering extra credit for people who find typos in the Textbook Extra credit for people who find mistakes for any/all eCampus quizzes or CPR assignments Now offering extra credit for students who send good clicker questions. If it becomes the basis for one used in class I will give you extra credit 50

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 51 Prep For Next Time – L6 Final Reading: –BBBHNM: All reading through Chapter 10 Reading Questions: –All reading questions through 10 eLearning Quizzes: –Chapter 7 Paper 2: –Calibrations and grading if you didn’t pass Paper 1, due before class on Monday

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math Tentative Due Dates Monday March 4 th (Today) –Paper 1 revisions due –Paper 2 assigned Monday March 11 th –No class, Spring Break. –Want feedback on a Paper 2 draft? Due today in eLearning Monday March 18 th –Paper 3 Assigned –Reading for Chap 11 and 12, EOC quizzes for 9 due Tuesday March 19 th –Paper 2 Text due in CPR and eLearning (1-day extension) Friday March 22 nd Want feedback on a Paper 2 draft? Due today in eLearning Monday March 25 th –Paper 2 Reviews due in CPR Wednesday March 27 th –Paper 3 text due in CPR and eLearning (2-day extension) Monday April 1 st –Paper 3 Reviews due in CPR 52

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 53 Prep for Next Time – P11 Reading: –BBBHNM 9 Reading questions: –Chapter 9 or the recommended reading End-of-Chapter Quizzes: –If we finished Chapter 8, end-of-chapter quiz due before next class (else just 7) Papers: –Paper 1 Resubmissions: CPR Calibrations due Monday –Start working on Paper 2 Paper 2 due Monday in CPR/Turnitin.com

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 54 Prep For Next Time – L13 Note: May change depending on how far we get in lecture Reading: –BBBHNM: All reading through Chapter 9 Pre-Lecture Reading Questions: –Through Chapter 9 End of Chapter Quizzes: –If we finished Chapter 8 then end-of-chapter quiz 8 (else just up to Chapter 7) Papers: –Paper 0: Was due Friday. Pass/Revise grades will be posted by the end of the night or after all regrades –Paper 0 Revision (if necessary – See eCampus score, not CPR Score): Open now, Text due Monday before class. All Calibrations/Reviews following Monday –Paper 1: Text was due before class. All Calibrations/Reviews due this coming Monday –Paper 2 (if we finished Chapter 8): Due Monday before class.

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 55 Prep for Next Time – P11 Reading: –BBBHNM 9 Reading questions: –Chapter 9 or the recommended reading End-of-Chapter Quizzes: –If we finished Chapter 8, end-of- chapter quiz due before next class (else just 7) Paper: –If you see problems with the grading of your Paper 1 send us email –Work on revision if needed

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 56 Prep for Next Time – P12 Reading: –BBBHNM 9 Reading questions: –Chapter 9 or the recommended reading End-of-Chapter Quizzes: –If we finished Chapter 8, end-of-chapter quiz due before next class (else just 7) Paper: –If you see problems with the grading of your Paper 1 send us email –Work on revision if needed –Start working on paper 2

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 57 Prep for Today (Is now due) – L11 Reading: –BBBHNM 8 End-of-Chapter Quizzes: –Chapters 2-6 Reading questions: –Two questions from Chapter 8 or recommended reading Paper 1: –CPR work was due today

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 58 Prep for Today (Is now due) – L12 Reading: –BBBHNM 9 End-of-Chapter Quizzes: –Chapter 7 Reading questions: –Two questions from Chapter 9 Paper 1: –Working on Revisions if necessary

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math Paper 0 Notes 59 If you believe you were misgraded on Paper 0 let us know ASAP If you did not pass all the pieces of Paper 0 you need to do a full revision in CPR including calibrations and grading –If you did well on the text, you don’t need to change much Pass/Revise Grading will be posted on eCampus after we have responded to all the requests for regrades You need a passing grade on paper 0 to pass the course

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math Sad Truth Every semester we have people who don’t listen to what is said in class and just look at their score on CPR and decide they have passed. Your score will be on eCampus. 60

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 61 Protons and Neutrons A carbon atom has 6 protons (blue) and 6 neutrons (grey) VERY tightly packed

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 62 Review of a Helium Atom Again look at the stuff as we zoom in http://bigbang.physics.tamu.edu/Figures/StolenAnimations/Animation_Atom.mpg

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 63 Exciting Atoms Atom in Ground State Proton Atom in Excited State

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 64 Excited Atoms Emit Light Photon with a specific energy Atom in Excited State Atom in Ground State

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 65 Analyzing Absorption Spectra Each element produces a specific set of absorption (and emission) lines Comparing the relative strengths of these sets of lines, we can study the composition of stars See only spectral lines for known atoms

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math Paper Notes ~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” 66

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 68 A “moving” Spectral Line… More Blue More Red

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 69 Light from the Stars A light bulb (or a star) will emit light at all wavelengths and thus produce a continuous spectrum

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 70 What about the Gas Outside a Star? What will we see if we look at the Gas outside the star? Light from the star will hit the gas, and we see the light from the gas itself

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 71 The light from excited atoms If the light hits a bunch of low speed atoms (typically call this a gas) at specific wavelengths it can create an emission spectrum Light excites electrons in atoms to higher energy states Transition back to lower states emits light at specific energies (wavelengths)

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 72 When atoms “get in the way” If a continuous spectrum of light passes through atoms, it can create an absorption spectrum Light excites electrons in atoms to higher energy states Wavelengths corresponding to the transition energies are absorbed from the continuous spectrum

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 73 The Spectra of Stars Inner parts of a star produces a continuous spectrum Outer parts absorb light at specific wavelengths  The light spectrum shows spectral lines!

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 74 Papers for the Course There will be three papers for the course –http://faculty.physics.tamu.edu/toba ck/109/WritingAssignments/http://faculty.physics.tamu.edu/toba ck/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 You should start thinking about your research paper topic

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 75 Helium 3 + Helium 3  Helium 4 + 2 Protons Creating Stable Helium Helium 3 Helium 4 Nuclear Reaction Proton

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 76 Writing Assignments 1.Short Assignment 1 is Due Wednesday March 4 th before the beginning of Class Instructions on how to turn it in are on the web 2.Short Assignment 2 is posted Currently Due Wed March 25 3.Research Paper is posted Stage 0 due March 30 th Stage 1 due April 13 th Final paper due the last day of class, May 4th Need to be finishing Unit 2 WebCT stuff

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 78 In Class Quiz Answer the following question: Why do we believe that stars are made of atoms?

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 79 Looking Forward With an understanding of how to build up nucleons, nuclei, atoms, molecules and matter here on earth we begin to have confidence that we can understand how to build up planets and moons, stars and galaxies in the sky If we can understand how the objects in the universe were formed we have a chance to understand where it all came from

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 80 Yet more remarkable Want to explain WHY most of the universe is Hydrogen Its not crazy to think that the reason its mostly hydrogen is because it started out as mostly quarks and just turned into Hydrogen, and not much else because its HARD to form the other stuff

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 82 Why Do Stars Shine? Stars are Hydrogen balls During the reactions of the Hydrogen (protons) creating heavier elements some of the light escapes This is why stars shine

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 83 Different Types of Nuclei How do we CREATE different types of nuclei in nature? Collisions between nuclei allow them to combine Decay of nuclei allow them to change

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 84 Summary Given enough nucleons and time you can eventually make helium Lots of energy released in the creation process From Helium and more protons you can make even heavier things…

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 85 Forming Protons Quark  Proton Nuclear Reaction Quark qqq  Proton

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 86 Now Nucleons Typically Combine in Nature Note about this video: They change the colors for the last slide!!! And the colors are screwed up for Helium on the last slide also!

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 87 Electron Orbits Electron orbits in the electron cloud are restricted to very specific radii and energies. r 1, E 1 r 2, E 2 r 3, E 3 These characteristic electron energies are different for each individual element

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 88 Spectral Lines Shine white light on a bunch of atoms: Prism shows the colors in white light going in After going through the atoms we are left with spectral lines –The excited states absorb and then re-emit in some different direction

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 89 Video here of photon coming in and exciting an atom then de-exciting… This explains excitations and then spectral lines. Prism of light coming from Page 54 of BHOT Jonathan! Feynman diagram on page 71 of BHOT.

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 90 History 1816: Spectral lines: von Fraunhofer Different lines from different atoms 1880 Huggins: Spectral lines indicate what the chemical elements are

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 91 Chemistry How do we make up the different kinds of atoms Different number of protons and neutrons in the nucleus and electrons Energy states Quantum mechanics Spectral lines.

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 92 Fundamental continued It turns out there are lots of different types of nuclei –This is the domain of nuclear physics It turns out that a nucleus is actually just a collection of protons and neutrons –Hydrogen: a single proton –Helium: 2 protons and 2 neutrons –Sodium: XX protons and XX neutrons –More on what holds all this together later… –More on what protons and neutrons are made of later (answer for now… quarks)

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 93 Moving towards the fundamental building blocks What is gas made of? –It turns out its made of molecules of different types –CN, others? What are molecules made of? –It turns out molecules are made of different types of atoms put together in different ways –Hydrogen, Helium, Sodium, Carbon, Nitrogen etc…

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 94 Spectral lines and Stars Atoms have excited states… these photons from the surface of the star excites the atom and is absorbed. Ok… they’re re-emitted later when the atom de-excites, but that goes in a random direction so we don’t see it.

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 97 The same force holds the nucleons together

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 98 How Atoms Combine Need this?

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 99 Making Molecules H20 picture from Giancoli

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 100 How atoms combine to form molecules?

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 101 Chemistry How do we make up the different kinds of atoms Different number of protons and neutrons in the nucleus and electrons Energy states Quantum mechanics Spectral lines.

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 103 BHOT 11 cont… Gravity continued… We think of gravity being caused by the exchange of virtual gravitons (not yet confirmed). Gravity is the weakest of the forces by a lot Two important things to know: –It acts even at long distances –It is (as far as we know) always attractive So what, if objects are really far away we might never notice gravity, but if they are really HEAVY then the attraction can be big. Earth going around the Sun. Others tend to cancel out.

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 106 Uncertainty Principle Uncertainty Principle determines the size of an atom and a nucleus DPDX > h

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 107 More so what… One more particle that we need to talk about, and that’s a photon (“gamma ray”). A photon is actually light (a gamma ray hits our eyes and that’s how we “see”) It also turns out that photons also play an important role in atoms Why do the electrons “orbit” the nucleus? The protons have positive charge, the neutrons are neutral, and the electrons are negatively charge. Since positive and negative charges attract each other, the electrons are attracted to the nucleus and that’s what keeps them “in orbit” –Again, the truth is MUCH more complicated than this, but its actually a good understanding…

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 110 How do the particles talk to each other? Feynman Diagrams

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 112 Chemistry We can put nucleons together in lots of different ways… Each different way corresponds to a different type of atom

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 114 Quantum Mechanics Some quick discussions of quantum mechanics (particles and waves, probability, small sizes and big energies) and What do we do for Quantum mechanics –QM and Gribbins' book? –The great experiments? Two slit? Bohr model? Heated metal? –Also mention to special relativity, general relativity, thermodynamics as applied to stars and blackbody radiation, quantum mechanics, and any other general scientific ideas? Later perhaps? –Need QM for now?

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 115 SHU 6 Anti-matter here? Page 149 When matter and anti-matter meet they annihilate and disappear in a burst of energy How could all the matter in the universe exist and be easily detectible if theoretically there should be just as much antimatter around? Either the matter and antimatter should have annihilated each other, or we ought to be able to detect as much antimatter in the universe, which we clearly do not. Evidence for anti-electrons (positrons) in 1932. Ends on page 153

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 117 Questions… How large are electrons and quarks? –We don’t know… that’s what I (and others) do for a living… What are they “made of”? Are they made of anything? Strings?

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 118 Fundamental Building Blocks This is a lecture on the fundamental building blocks of nature… Need a textbook for this… Charm of Strange Quarks??? Where is my lecture from Physics 101?

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 119 BHOT 11 cont… Force 2: Electromagnetic force Most people know about this also, it is what causes the interactions between electrically charge particles that we know and love Electrons and protons Electrons and quarks Ignores electrically neutral particles such as neutrons and neutrinos.

Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 1 Big Bang, Black Holes, No Math ASTR/PHYS 109 Dr. David Toback Lecture.

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Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 1 Big Bang, Black Holes, No Math ASTR/PHYS 109 Dr. David Toback Lecture.

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Presentation on theme: "Physics We Need Topic 4: Nuclear Physics & Chemistry Big Bang, Black Holes, No Math 1 Big Bang, Black Holes, No Math ASTR/PHYS 109 Dr. David Toback Lecture."— Presentation transcript:

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