preptest 66 S1 #27 (RC) Forum

[june2014]

I picked (B) instead of (E) and I'm still not sure why (B) is incorrect. I understand that (E) is directly from the passage in lines 30-34, but can't (B) also be true? Earlier calculations indicating that atoms could be split was reevaluated (=proved with experiments) and confirmed by Meitner and Otto. Am I misunderstanding/misinterpreting something here? Any help would be much appreciated!

[Christine (MLSAT)]

Ooof, I sympathize with you on this question! This is a great example of how easy it is to add tiny bits of data/detail to the passage in our own minds that seem entirely plausible or reasonable - and how this can lead us straight into traps. You've got to accept the mantra of "line references, or it didn't happen".

So, there are a few things here that make (B) unsupported. It may seem a plausible, reasonable answer - but if we don't have direct and fairly explicit evidence in the passage for it, we must eliminate it.

First, let's deal with Otto Hahn, in paragraph 3. His experiments weren't for the purpose of proving nuclear fission, nor was he even really thinking of that as a possibility. Lines 18-25 show that while these physicists were aware of the possibility of nuclear fission, they just weren't making the connection to these experiments. As a result, there's no evidence that any of them, including Otto Hahn, were even reviewing the calculations of theoretical physicists mentioned in lines 16-18.

So, that means that they ONLY place I might find evidence for "reevaluated calculations" is in paragraph 4. Perhaps Lise Meitner? We know she 1) recognized the signficance, 2) coined the term "nuclear fission" and 3) submitted her conclusion for publication. In any of that, did she "reevaluate calculations"? I have no idea!

The last sentence tells us that afterwards, scientists "rushed to corroborate the findings" - that means they rushed to replicate the experiments like that which seems to have split uranium into barium and technetium. Would that involve "reevaluat[ing] calculations"? I don't know!

So, there's no explicit evidence in the passage that *anyone* actually reevaluated those calculations.

Take a look at how hard you have to work to create justification for (B), and how many gaps in the passage's information you have to fill in to get there. Now take a look at the evidence for (E) - "these products remained unidentified partly because precise chemical analyses were hampered by... the dangers of working with highly radioactive materials". Clearly, the physics community recognized the dangers of working with radioactive substances! Notice the difference in the support you feel is behind each answer choice.

This is the line you want to learn to draw in future RC questions - the line between 'there is explicit or nearly explicit support for this answer in the passage' and 'this answer seems plausible, but I can't find explicit support for it in the passage'.

Thoughts?

[june2014]

I think I got it--so, though earlier calculations indicated that it should be possible to break atoms apart, it wasn't explicitly stated in the passage whether Lise Meitner and Otto Hanh “reevaluated" these earlier calculations in the process of reaching their conclusion on nuclear fission, and the passage also doesn't tell us whether the scientists who "rushed to corroborate the findings" reevaluated earlier calculations in doing so.

So for (B) to be the answer, I need to make assumptions that weren't explicitly stated in the passage, whereas (E) is clearly stated in lines 32-34, and that's why (E) is the answer.. Thank you for your explanation, that cleared up my confusion! I should keep reminding myself, "line references, or it didn't happen."