This simulation is an opportunity to teach about several features of how science works:
Students learn by immersion in the historical context, coupled with a "retrospective" discussion afterwards.
- funding scientitifc research
- scientific uncertainty
- scientific communication (openness)
- science and politics, especially weapons.
The first challenge, then, is to recreate the historical context. There is a short background (images can be extracted for an image-only presentation), which introduces the events and main characters. An excellent resource is Richard Rhodes' Pullitzer Prize-winning The Making of the Atomic Bomb, Chapter 10 on "Neutrons." Guidance is provided for each role. Several resources are available online or in books (some available online through Google Books; or may be purchased used).
The Guiding Questions provide a convenient agenda for the meeting. The teacher may take the role of Lyman Briggs and lead the meeting, or may assign the role to a student as an occasion to develop leadership/discussion-leading skills.
The positions are summarized below (page numbers refer to Rhodes, 1986):
- What is the feasibility of a sustained nuclear reaction? (Can nuclear power actually be harnessed?)
- (+) Szilard: enough neutrons that chain reaction not ruled out (>50%?)
- (–) not known w/o U235 or measurement w/ moderator
- (–) Roberts(DTM): fast neutrons unlikely 
- a moderator is needed to slow neutrons for U235 fission (natural)
- Fermi: oriented to natural U 
- Is building a bomb a realistic enough possibility to consider it seriously at this point?
- (–) too heavy to transport by air? [Einstein & Sachs letter]
- (–) Roberts: not of natural U [315-16]
- (–) separation of U235 is too costly and amounts too small [297, 294]
- (–) development time for weapons is 2 or more years ; war likely resolved by then?
- Considering international politics, should research proceed on the assumption that one will be built, if feasible?
- (+) Ross Dunn (Navy): a source of power without burning? ==> propsect for powering submarines [p.295, 303!]
- (+) Germans halt sale of U from Czech mines [Einstein letter]
- (+) Szilard on Wells' The World Set Free, Shape of Things to Come: role of deterrence [Ch. 1]
- (–) This is a "European" war only 
- (–) Adamson (Army): role of morale v. weapons in winning war 
- (+) contingency of German pursuit of bomb
- (–) time needed even for Germans
- What research on nuclear physics is now most important? How much will it cost, and who will fund it?
- graphite: $33,000
- 2 ways to separate U235: Onsager (gaseous), Nier (mass spectrograph) 
- Sachs (letter to FDR): leading chemical and electrical companies; foundations
- (–) status of aging Navy vessels -- military money needed to update standard fleet
- Should the research ever be kept secret?
- (–) Bohr & international community of science 
- (–) Otto Hahn: balance of power 
- (+) Teller, Szilard, Wigner (even though mutual deterrence as key to peace?) [note all are refugees from Hungary, with a strong anti-German bias]
- (–) Fermi -- agreement broken on earlier publication moratorium (secrecy will not hold, and only damage priority claims)
The historical decision reflected the information above (see end of chapter by Rhodes). The science was so uncertain at the time (1939) that the prospect of a functional weapon did not seem likely. Militarily, the usefulness of a new weapon did not seem immediately important, especially relevant to other needs. There was no precedent in the U.S. for supporting basic research related to defense or weapons (contemporary weapons research was development based on known principles). The openness of international science communication was a recent triumph, not to be forsaken lightly.
Nevertheless, students tend to read the history "backwards" and insist that research must go forward, be kept secret, and be funded by the government. The mismatch with history can nonetheless be an important part of the lesson, developed in discussion afterwards. It underscores how difficult it is for us to understand the uncertainties of our own time, because we cannot see them functioning in the past. The epilog is a valuable reminder of how science works, blind to the future.