big bang, black holes, no math astr/phys 109 dr. david toback lecture 4

IntroductionTopic 3: Going Small

Big Bang, Black Holes, No Math

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ASTR/PHYS 109Dr. David Toback

Lecture 4 & 5



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Prep For Today (is now due) – L5

• Reading (should already have been completed)– Required: BBBHNM: Chapter 1-4

• Pre-Lecture Reading Questions (PLRQ)– All 6 PLRQ quizzes in eCampus (was

already due)– CPR Stage 2

• End-of-Chapter Quizzes– Chapter 2

• Papers– None assigned– First one will be assigned when we do

Chapter 6



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Next Topic: Going Small

•Finished looking at various things in the universe going from the sizes we know to the VERY big

•Next we do the very small•Why? If we want to

understand the universe we need to know what’s in it and what its made of

•Why and how did it get to be the way it is?



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Starting out with small things

10 centimeters, or 0.1 meters, or 10-1 meters.About 3 inches

A baseball is a size we know from everyday experience



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Getting smaller

Something smaller you can see with your eyes0.01 meters,

(10-2 m) or 1 cm, or about a 1/3 of an inch



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Much smaller

A simple dust mite is barely visible with the naked eye

Into the realm of biology10-3 meters or 1 millimeter



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A human hair

Looking a the side view of a single hair

10-4 meters



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Closer still…

A single red blood cell

10-5 meters



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Further still

An HIV virus which is one of the bigger known viruses10-6 meters



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Small Virus

A polio virus which is known to be one of the smaller viruses

10-7 meters



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The Double Helix

A close up of the helical structure of DNA

Starting to get into Chemistry10-8 meters



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An Atom

10-9 meters or 1 nanometer10 million in a cm

•What we’re seeing is the electron “cloud” as it goes around the atom•Kinda like the blades of a fan

•The realm of Physics



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Inside an Atom

•Snapshot in time of 2 electrons “orbiting” the nucleus•Atoms are “composite” things, not fundamental

10-10 meters



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The Central Part of the Atom

• The electrons are outside our field of view

10-11 meters



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Homing in on The Nucleus

•Still zooming into the center of the atom

•The atom is mostly empty space

10-12 meters



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The Structure of the Nucleus

Can just start to see the “stuff” inside the nucleus

The nucleus is not fundamental

10-13 meters



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Protons and Neutrons

•A carbon atom has 6 protons (blue) and 6 neutrons (grey)

•VERY tightly packed10-14 meters



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Inside the ProtonThree quarks inside the proton–Protons are composite–Quarks are fundamental

10-15 meters



Other Fundamental Particles?

•Electrons and quarks (as far as we know) are fundamental

•Lots of other fundamental particles

•Recently discovered the Higgs Boson

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Anti-Matter Each fundamental particle has an anti-

matter version which is also fundamental

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Protons are stable live foreverNeutrons outside a nucleus are

unstable can decay

Neutron Proton + Electron + Neutrino

Stable and Unstable Particles

Neutron

Proton

DecayElectron

NeutrinoNote that this only happens when

Neutrons are by themselves (not in an

atom)



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Inside an Atom

If an atom were the size of a large city, then the neutrons and protons would be the size of a person, and the electrons and quarks would be smaller than a small freckle

http://bigbang.physics.tamu.edu/Figures/StolenAnimations/Animation_Atom.mpg



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Summary: The “Small” Sciences

cm 10-10 m 10-14 m 10-15 m

u

<10-19 m

10-9 m

Matter Molecule Atom Nucleus QuarksProtons &Neutrons

Electrons

<10-19 mtop, bottom,

charm, strange,up, down

Chemistry

Atomic Physics

NuclearPhysics

Particle Physics



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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?

•Are there other fundamental particles we haven’t discovered?



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Prep For Next Time – L4• Reading:

– No new reading– Unit 2 reading assigned next time, but

likely due Feb 9th• Pre-Lecture Reading Questions

– Stage 2 in CPR for Unit 1 due Wednesday before class

– Stage 1 in CPR for Unit 1 Revision will be assigned after grades are posted (will happen after next class)

– Stage 1 for Unit 2 will be assigned Next class, probably due Feb 9th

• End-of-Chapter Quizzes– If we finished Chapter 3 then End-of-

Chapter Quiz 3 (else just Chapter 2)



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Prep For Next Time – L5

•Reading:–Unit 2

•Pre-Lecture Reading Questions–Stage 1 for Unit 2 due before

Class –Stage 1 in CPR for Unit 1

Revision will be assigned after grades are posted

•End-of-Chapter Quizzes– If we finished Chapter 3 then

End-of-Chapter Quiz 3 (else just Chapter 2)



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Clicker QuizA muon is observed to decay into an

electron and two different neutrinos. Is a muon considered a fundamental particle?

a)No, because it has the electrons and neutrinos inside it so it can't be fundamental.

b)Yes, because it isn't composed of electrons and neutrinos, it just decays into them

c)No, because fundamental particles can't decay



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Clicker QuizQ: What does it mean for an electron to

be "stable?"a)It is balanced with exactly one protonb)Its orbit ring exists in one plane (no

wobble)c)It has reached minimum size (10-19 m) d)Undisturbed, it can go on living

forever and evere)They don't appear to be made of

anything smaller



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Prep For Next Time – L3•Reading:–BBBHNM: Chap 3 and 4

•Reading Questions:–Two questions from Chapter 3 or the recommended reading–Two questions from Chapter 4 or the recommended reading

•eLearning Quizzes–If we finished Chapter 3 then end-of-chapter quiz 3 (else just 2)



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Prep For Next Time – L4•Reading:–BBBHNM: Chap 4

•Reading Questions:–Two questions from Chapters 4 if you didn’t complete already

•eLearning End-of-Chapter Quizzes–If we finished Chapter 3 then end-of-chapter quiz 3 (else just 2)



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Prep for Today (Is now due) – L4

•Reading: –Required: BBBHNM: Chapter 4

•eLearning End-of-Chapter Quizzes:–End-of-Chapter Quizzes for Chapter 2

•Reading questions:–Two questions for Chapter 3 and two questions for Chapter 4



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Prep For Today (is now due) – L4

• Reading: – Required: BBBHNM: Chapter 1-4– Recommended Reading:•BHOT: Chap. 1-3•SHU: Chap. 1-2•TOE: Chap. 1

• Pre-Lecture Reading Questions– Three questions from Unit 1

• End-of-Chapter Quizzes– Chapter 2



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Full Set of Readings So Far

•Required: BBBHNM: Chap 1-4•Recommended:–BHOT: Chap. 1-3–SHU: Chap. 1-2–TOE: Chap. 1



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Other Fundamental Particles?

• Electrons and quarks (as far as we know) are fundamental

• Lots of other fundamental particles

• There is also anti-matter– Each fundamental

particle has an anti-matter version which is fundamental

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Prep For Next Time – L4

•Reading:–BBBHNM: Chap 5

•Pre-Lecture Reading Questions:–Two questions from Chapter 5

•End-of-Chapter Quizzes–If we finished Chapter 3, then do 3 (if not, just 2)



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Prep For Next Time – L4• Reading:

– Required: BBBHNM Unit 2 (Chapters 5-9), will be due Monday

– Recommended Reading:• See P3 of

http://people.physics.tamu.edu/toback/109/Syllabus.pdf

• Pre-Lecture Reading Questions– Unit 1: Stage 1 Revision (if needed), due

Monday. Pass/Revise grades posted on CPR later this week• Will post the assignment after class

– Unit 2: Stage 1 due Monday• End-of-Chapter Quizzes

– If we finished Chapter 3 then End-of-Chapter Quiz 3 (else just Chapter 2)

big bang, black holes, no math astr/phys 109 dr. david toback lecture 4

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