Reading comp PrepTest 143 · Section 2 · Question 22

Passage

Questions 21-27  .        To glass researchers it seems somewhat strange  . that many people throughout the world share the Remaining source text redacted.
Passage walkthrough
Passage SummaryTopic: Science

Paragraph 1
  • Paragraph note
    • A myth is presented, what partly led to it is proposed, and background info on glass
  • Views, minor Meta-Structures, and the author's attitude
    • Myth (weird to glass experts) - Glass flows down like a liquid
    • Origin - Unknown, but probably in part because of mistake on atomic structure
    • Science/Structure - Liquid and glass similar, but cooling it makes it an amorphous solid
Paragraph 2
  • Paragraph note
    • A related phenomenon is introduced, and an explanation is debunked in a study
  • Views, minor Meta-Structures, and the author's attitude
    • Phenomenon - Medieval cathedrals have glass thicker at the bottom
    • Explanation - Glass flows down
    • Author - Zanotto study debunks this
    • Zanotto - Gravity can cause solids to flow, but it'd take longer than the universe
Paragraph 3
  • Paragraph note
    • Zanotto's conclusions are explained
  • Views, minor Meta-Structures, and the author's attitude
    • GO glass - flows best - would take trillions of years
    • Impurities would lessen that, but not by that much
    • Flow requires 350+C (temp)
    • Author - Study shows what scientists had known
Paragraph 4
  • Paragraph note
    • A true explanation for the earlier phenomenon is noted
  • Views, minor Meta-Structures, and the author's attitude
    • Explanation for thicker bottoms of medieval cathedral glass - Manufacturing processes
    • Early (until 19th C) - Glass blown, which thickened some edges, and those were placed down for stability
    • Later - Pulled from rod, making it more uniform
    • Now - Molten tin floating, making it extremely flat
Main Point:
Zanotto has shown that the persistent belief that glass flows like water and this explains the thicker bottoms of medieval glass is wrong, as it would take longer than the universe has existed for that to happen, and it's probably the result of manufacturing methods.

Key Lines:
Lines 1-5 - A common belief and the fact that scientists think it's weird are introduced
Lines 8-10 - A partial reason for it is stated
Lines 20-21 - A phenomenon is noted, and the Author says that she believes an explanation related to the common belief has been debunked
Lines 44-46 - An alternative explanation is presented

Meta-Structure:
Common Belief/New Belief - This passage introduces a persistent belief shared by many (Line 3) before showing it's wrong. This metastructure is very common on the LSAT, and especially so in science passages.

Phenomenon/Explanation - Here, the Author presents a phenomenon—medieval glass is thicker at the bottom (Lines 20-23). After ruling out one explanation (Lines 20-23), she presents another (Lines 44-46).

Last Thoughts:
Remember - You don't need to know science! We don't care if you know what an amorphous atomic structure is, or if you know the atomic weight of geranium is (it doesn't have one, it's a flower! It's germanium, but it still doesn't matter). What we do want is you to tag these phrases so you can find them in case it asks about them in context.

Second, the main point. This passage has a lot going on, and we want to make sure that our anticipation of the main point is comprehensive. As such, we need to make sure that it includes the phenomenon being explained, the incorrect explanation (in some way), and the explanation put forward by the Author, along with how certain she is about each element (mainly the debunking and the new explanation).

Finally, this passage brings up a really important thing to note—and it's especially common in science passages. That's the certainty of the verb that the Author uses to describe proof (in this case, studies). There's a world of difference between a study that argues a common belief is wrong, one that provides evidence it's wrong, and one that proves it's wrong. If the Author says "argues," then we don't know her opinion on it. If she says "provides evidence," then she thinks there's a good case, but she's not sold. And if she says the study "proves" the belief is wrong, then the Author is on board. "Debunks" here is in the third camp—you can't use that verb if you don't think that the study has disproved the belief with certainty. Start to analyze these words when the Author introduces evidence!

Question prompt

The passage most helps Remaining source text redacted.
Why the credited answer is right

Credited answer: B

The notes below walk through why it fits the stem and how to eliminate the rest.

Question Type

Science

Answer choices

  1. A
    What is one way Remaining source text redacted.
    Why choice A is not credited
    Incorrect. (Lines 46-49) If there's an answer to this question, it would be in Paragraph 4. However, there, it says that one technique was used until the 19th century, so it doesn't delve into differences between the medieval period and the 17th century, instead lumping both periods together with the same technique.
  2. B
    What is one way Remaining source text redacted.
    Why choice B matches the stem
    Correct. Question Type:
    Must Be True

    Strategy Overview:
    Use our overall understanding of the passage to decide whether to dig into an answer, then use our notes and the passage to see if it's correct

    Answer Anticipation/Relevant Lines:
    There's no guidance in this question stem as to what we're looking for. It doesn't ask for something that's explicitly answered in the passage, but we also should stray too far from the text. As such, all we can do is reiterate the main point and then use our notes and overall understanding to analyze the answers. The main point, as we outlined it, is:

    Zanotto has shown that the persistent belief that glass flows like water and this explains the thicker bottoms of medieval glass is wrong, as it would take longer than the universe has existed for that to happen, and it's probably the result of manufacturing methods.

    Answer Explanation:
    (Line 46; Line 55) Similar to (A), the answer to this question would show up in Paragraph 4. We also just noted in analyzing (A) that the paragraph does mention the 19th century. Scanning through it, we can see that it talks about what is done "[t]oday," so this is the correct answer.

    Key Takeaway:
    Three of these answers deal with a timeline. (A) and (B) talked about specific centuries, and (C) talked about "prior" times. As with LR, timelines are important in RC, so be sure to note it. If you look at our Important Details/Thoughts for Paragraph 4, it included a sketch of that timeline.
  3. C
    Was glass ever used Remaining source text redacted.
    Why choice C is not credited
    Incorrect. (Lines 46-47) The passage lumps all time periods before the 19th century together in talking about window pane manufacturing techniques, and there's no mention of earlier times or of the medieval period being the first era with glass windows, so an answer to this question can't be found in the passage.
  4. D
    Are unevenly thick stained-glass Remaining source text redacted.
    Why choice D is not credited
    Incorrect. (Lines 32-34) The passage notes that germanium oxide glass flows more easily than other types, but this would still take trillions of years to sag. So we know that unevenly thick GO glass isn't due to sagging. But we also don't know if germanium oxide glass is ever made using the blow-and-flatten method—maybe most glass, and all medieval glass, is germanium oxide! Since we don't know, we can't answer this question.
  5. E
    How did there come Remaining source text redacted.
    Why choice E is not credited
    Incorrect. (Lines 35-36) These impurities are mentioned in Paragraph 3 as a factor in the speed of sagging, but there's no discussion of how the glass ended up with those impurities.

What this tests

Question analytics

Based on historical answer selection rates for this question.

Answer choice distribution

  1. A 7%
  2. B Credited 72%
  3. C 3%
  4. D 6%
  5. E 11%

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