Manhattan Project — Daily Schedule — Term 4

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Week 1 — Discovery of Mysterious Radioactivity

Preparation for Tuesday, Jan. 10 — Preface and Chapter 1 (Overview) from The History and Science of the Manhattan Project, 2nd Edition, 2019, by Bruce Cameron Reed
Tuesday, Jan. 10 — Discussion of Preface and Chapter 1, particularly the reasons for studying the Manhattan Project at a semi-technical level, key dates in WWII (1939, 1941, and 1945) — First assignment, due Tuesday, Jan. 17 (see below) — Remainder of class, lecture on Elements and Energy
Preparation for Friday, Jan. 13 — pp. 19-36 of Chapter 2 of The History and Science of the Manhattan Project, 2nd Edition, 2019, by Bruce Cameron Reed — Ignore Equations 2.1-2.8 on pp. 26-27. They are college sophomore math. I will be able to explain them to you. Maybe on Friday.
Friday, Jan. 13 — We analyzed the overlapping discoveries and terminology of early nuclear chemists and early particle physicists: α particles, β rays, γ rays, electrons, and X-rays (two pairs in these five are arguably redundant) — We discussed the cathode ray tube (also known as the Crooke’s tube) — We did an accurate, but without-calculus derivation of the fundamental exponential decay equations (equations (2.1)-(2.3)) — We did a naive definition of the mol, and then we discussed how isotopic abundance and the mass defect both force upon us a more precise definition of mol and N_A — We started using three hand-outs: Isotope Table, Isotope Plot Color-Coded by Decay Type, and the Binding Energy or Mass Defect Plot (and we will continue learning to use these handouts next time)

Week 2 — Investigation of the Atom and the Nucleus

Preparation for Tuesday, Jan. 17 — Email me Assignment 1 - Essay Draft before class — Continue reading in Chapter 2 to p. 45 — The author’s discussion of major discoveries has often been insufficiently detailed in terms of what the actual experiments were (as opposed to the experiment’s results) — Therefore, individually research and prepare as follows: Trey, Crooke’s Tube and Cathode rays (the electron); Brandon, Roentgen discovers X-rays; Anna, The Curies isolate polonium and radium; Mac, Aston discovers many isotopes with mass spectrometry — Say as much as you can and think is important in each of these discoveries, especially how the experiments were actually done (feel free to share handouts of materials that you consulted)
Tuesday, Jan. 17 — Start Assignment 2
Many questions queued up from presentations and Tuesday’s reading.
From presentations (these I have looked up the answers to):
- Why do electrons come out of the cathode of a cathode ray tube when chemists say that the cathode is the electrode where electrons go into the battery? A: A single piece of wire has two ends. The end in the Crooke’s tube we call the cathode, because it emanates electrons. The other end of this same wire is the anode to the electrochemist because it is taking in electrons from the battery solution.
- Does the cathode ray tube have to have phosphor on the glass to glow? A: No, the glass glows green even without phosphor.
- Where did the Curies get the pitchblende (uraninite) form which they concentrated Polonium? A: From the Joachimasthal mine in Austria. (For more detail, A Short History of Polonium and Radium by Jean-Pierre Adloff is wonderful.)
- Pierre Curie was killed in Paris in 1906 after falling under a carriage. Marie Curie and André Debierne isolated 0.1mg of polonium from uranium ores in 1910. How much ore did they Marie Curie and André Debierne start with before they isolated Polonium? A: Tons!
From Tuesday’s reading:
- What is the positron? A: We did an extensive discussion of anti-particles and the observed fact that the universe is electrically neutral and has a preponderance of protons, neutrons, and electrons.
- Why do atoms decay? Do all atoms decay? Why do some atoms decay faster than others? A: We went all the way down to the 1967 Glashow-Weinberg-Salam theory of the weak interactions
- How can I make a radioisotope? What is alpha bombardment? A: We discussed the Joliot-Curie experiment where alpha particles from Polonium bombarded Beryllium?
- What makes something choose to alpha decay vs. a beta decay? A: We discussed the Binding Energy or Mass Defect Plot and the Isotope Plot, and that Iron-56, Iron-58, and Nickel-62 are all very close to the sweet spot with the least mass per nucleon. Decays tend to move an isotope toward the sweet spot. We looked carefully at Fig. 2.12.
- The answer to the question above leaves the answer to the following question vague: Which of Iron or Nickel is actually the most tightly bound? A: This is advanced, but if you want, read this StackExchange discussion or read Section 2.5 of Reed carefully (most people should skip it)
Preparation for Friday, Jan. 20 — At the beginning of class, turn in Assignment 2 — Assignment 2 Solution — For reading, go to end of Section 2.2 (p. 60) but skip over the equations on p. 50 about the Coulomb barrier, which I will cover next week
Friday, Jan. 20 — Finish first set of short presentations: we have done four, so that leaves Norah left to present Rutherford and collaborators discoveries that (a) the positive charges of an atom are concentrated in a tiny nucleus, and (b) that alpha particles are Helium nuclei — Worked through all the old and new questions queued up above — Finally, from today’s reading we started into why the neutron is so effective as a particle for bombardment (Reed pp. 59-60), and next time we will go into detail on the Coulomb barrier

Week 3 — The Neutron is Discovered

Which completes the rough outline of nuclear physics and eliminates the Coulomb barrier

Preparation for Tuesday, Jan. 24 — Reading: Finish Chapter 2 - Except skip the final section (Section 2.5)
Tuesday, Jan. 24 — Norah did a detailed job of describing both: (a) The apparatus used by Rutherford to discover that the positive charge in a nucleus is concentrated at the center, and (2) The apparatus that Rutherford’s associates used to discover that the alpha particle was the same as a Helium nucleus — We delved into spectroscopy enough to understand how spectroscopy was used to identify Helium (it is very hard to identify using chemical reactions, because noble gases, He, Ne, Kr, Ar, Xe, and Rn don’t react — that’s why they are called noble gases) — We went deep into understanding The Coulomb Barrier — We finished with Rutherford’s declaration that making a chain reaction with protons is “talking moonshine” and Szilard’s response that “pronouncements of experts that something cannot be done have always irritated me.” — In 1934 Szilard even patents the idea that power and explosives can be created using chain reactions of neutrons (but because of the military potential, the patent is not published until 1949)
Preparation for Friday, Jan. 27 — At the beginning of class, turn in Assignment 3 — Assignment 3 Solution — Read through Section 3.1 of Reed — Bring questions from the Problem Set 2 solution that I distributed, and about Problem Set 3 that you are turning in, in addition to the new reading
Friday, Jan. 27 — We applied energy and momentum conservation (and used both the relativistic formula for energy and momentum and the non-relativistic formula for energy and momentum in order to analyze the Photon-Proton Collision which was fundamental to hypothesizing the existence of the neutron — We also discussed cross-sections, the barn, and the meaning of the log-log graph in Fig. 2.27 before turning to the evidence for fission being found by the now-fragmented team of Meitner, Hahn, and Strassman, on December 17, 1938 (Hitler has already taken Austria and Meitner has fled to Holland)

Week 4 — Fission is Discovered

Which raises the possibility of fission chain reactions to make bombs and generate power

Preparation for Tuesday, Jan. 31 — Continue Chapter 3, Reed Sections 3.2-3.6
Tuesday, Jan. 31 — We had three presentations: (1) Trey: the timeline for the discovery of transuranic elements, especially plutonium, (2) Mac: possible explanations for rift between Hahn and Meitner, and (3) Norah: what are the primary ways that Uranium-235 fissions — Topics discussed following presentations: mass spectrometry (and explaining why it is analogous to spectroscopy), neutron-richness and instability of fission products, chemical similarities of elements and isotopes produced in fission to the more common elements that the body uses, the empirical Z/N stability pattern that strongly favors even Z and even N
Preparation for Friday, Feb. 3 — Finish Chapter 3 (Reed Sections 3.7 and 3.8) — At the beginning of class, turn in Assignment 4 — Assignment 4 Solution — For Friday, Mac will prepare a discussion of the most recently-discovered transuranic element, element number 118, the specific name and isotope being Oganesson-294, focusing on the technique and cost of production, the method of detection, and the half-life
Friday, Feb. 3 — Hand out copies of each other’s mock journal entries to read for Tuesday — Mac: Element 118 presentation — Discussed droplet model of fission, including surface tension, typical units are MeV per square Fermi (1 Fermi = 1 femtometer = 10^-15 — Pushed billiard ball dropping into a pocket analogy — Finished Chapter 3 — Frisch and Peierls have interesting biographies, as do Meitner, Hahn, and Strassmann (actually, most of these 1930s physicists have fascinating biographies) — Hand out supplementary articles on Meitner and Frisch Conceive of Nuclear Fission, Portrait of Lise Meitner and Meitner’s Escape from Germany to Sweden

Week 5 — Manhattan Project Conceived

And the outlines of its administration emerge

Preparation for Tuesday, Feb. 7 — Read each other’s mock journal entries — Read the two handouts on Meitner from Friday — Read first half of Chapter 4 (4.1 to 4.6, pp. 125-153)
Tuesday, Feb. 7 — Discussion of first half of Chapter 4 and readings
Preparation for Friday, Feb. 10 — Read second half of Chapter 4 (4.7 to 4.11, pp. 153-179) — Short research topics (about 10 minutes, including questions): Norah, the thinking of Vannevar Bush and whatever skeptics you can find; Mac, what was China’s role; Trey, why would Japan’s leaders thought it was a strategically good idea to attack our naval base in Hawaii; Brian, Lise Meitner’s living conditions at the time she was expelled from the KWG
Friday, Feb. 10 — Discussion of remainder of Chapter 4 and readings continued — Discussion of conservation of energy and momentum problem on Assignment 4 — Presentations from Norah and Trey (Mac’s presentation delayed to Tuesday)
Sunday, Feb. 12 — of class, turn in Assignment 5 — Assignment 5 Solution

Preparation for Tuesday, Feb. 14 — Study the pile program (the beginnings of nuclear reactors), pp. 183-198 of Chapter 5
Tuesday, Feb. 14 — Mac’s presentation on China’s role in the war — Discussion of remainder of Chapter 4 — Discussion of pile program material in Chapter 5 — Drop by my place to see a piece of atomic pile
Preparation for Friday, Feb. 17 — At the beginning of class, turn in Assignment 6 — Assignment 6 Solution — Study the electromagnetic and gas diffusion programs pp. 199-222 of Chapter 5
Friday, Feb. 17 — Mac’s Presentation on CANDU reactors — The Y-12, K-25, and U-25 Enrichment Programs

Week 7 — Term 4 Exam — Shakespeare Festival

Tuesday, Feb. 21 — Term 4 Exam (open book and note)
Friday, Feb. 24 — No class (due to Shakespeare festival)

Weeks 8-14 are in Daily Schedule-Term 5