LSAT 136, Section 1, RC Passage 4, Nuclear Fission

This is an explanation for passage 4 of LSAT preptest 66, the June 2012 LSAT. This passage is about how scientific discoveries often look easier in retrospect. The passage gives the specific example of the accidental discovery of nuclear fission from uranium experiments.

This section has paragraph summaries and an analysis of the passage, links to the explanations for the questions are below.

Paragraph Summaries

1. Scientific discoveries often look easy in retrospect. Nuclear fission is one example. Uranium bombardment experiments produced evidence that we could do fission, but scientists took a while to realize what they had done.
2. There was a theoretical basis for fission, but the uranium bombardment experiments weren’t undertaken to produce fission. The researchers weren’t expecting fission to occur.
3. Researchers were puzzled by the results of bombardment, and assumed the results were close to uranium.
4. Hahn discovered that the experiments had produced barium.
5. Scientists realize that they’ve been doing fission.

Note: 3 and 4 refer to the first and second halves of paragraph 3.

Analysis

The first sentence is the most important part of the passage. It shows the author’s theme: science sometimes seems obvious when we look back at it. But science is actually very complicated and uncertain.

Scientists will often assemble much evidence, but then take a while to piece everything together. This makes sense. Science is a complicated business, and we have the benefit of hindsight when we look back.

The author introduces the example of nuclear fission in order to illustrate his claim about the messy nature of science. Fission is not the main point. It’s just an example. See line 5, ‘a case in point’.

That said, fission is an extended example, so it’s important to understand what’s going on. There were two groups of scientists.

First, there was a theoretical group that claimed atoms could be broken apart. But they couldn’t prove anything.

Second, there was a group of experimental physicists. They were bombarding uranium with neutrons. We don’t know why they were doing this, but we do know they weren’t expecting to break apart uranium atoms.

So they were puzzled by their results. They didn’t bother analyzing the chemicals produced by bombardment, because it was hard to do. But they also didn’t bother because they assumed they would find only uranium.

Eventually, Hahn did an analysis and figured out the the results included barium. Meitner then realized that the scientists had been splitting atoms.

Once Meitner figured this out, then research teams were easily able to replicate the results and produce fission. The big problem had been that nobody realized fission could be done.

There’s a large variety of research teams mentioned. The point is that even multiple teams of very smart scientists had no idea what was going on.

Once you figure something out, the solution seems obvious. But it’s not. Before you solve the problem it can seem very hard. You have all the information necessary, but it takes insight to piece things together in the right way.

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