PrepTest 143

Incorrect. (Lines 18-19; Paragraphs 2-3) First, this answer should be suspect because the Author spends the entire passage arguing that glass doesn't flow down over time, and this answer says that it behaves as a liquid. Second, the end of Paragraph 1 states that glass below a certain temperature takes on the physical properties of a solid—in other words, it won't behave as a liquid.

Incorrect. (Lines 28-30) Similar to (A), this answer flies in the face of the main point of the passage. The Author argues that glass doesn't change shape in any reasonable time period—it'd take longer than the age of the universe. That's well over a few millennia, so this answer is incorrect.

Incorrect. (Lines 16-19) The passage notes that glass, cooled below the transition temperature, will take on properties of a solid. However, if it's heated to that point, then it might revert to molten/liquid glass.

Correct. Question Type:
Must Be True

Strategy Overview:
Find the section discussing the atomic structure of glass, read it to get the details down, and then find an answer reflecting them

Answer Anticipation/Relevant Lines:
Ugh, these science questions can be rough. However, remember—the LSAT isn't going to require scientific knowledge or inferences that are based in science. So we should be sure to tag any section that has complex science so we can find it (at least one of our instructors literally writes "science—{topic}" next to it), and then rely on the language on the page to guide our way to the answers.

Here, we noted that the end of the first paragraph talked about the atomic structure of glass. Heading back there, we can see a few things. First, the atoms aren't arranged in a fixed crystal structure (whatever that is). Second, liquid and solid glass both exist, but they have similar structures but different thermodynamic properties (again, whatever that means). Finally, it has a several-hundred-degree "glass transition temperature"—above it, it is a liquid with an amorphous atomic structure, but below it it has the properties of a solid while still retaining that amorphous atomic structure.

All that said, we need to be careful here when we review the purpose of this information. This section is meant to highlight what the Author thinks at least partially inspired the persistent belief that glass does flow like a liquid. That might lead you to think that this information does support the view that glass has liquid-like properties. But note that the Author says that view is based on a "misunderstanding" of the atomic structure of glass. In other words, people think science backs up their view, but it doesn't really. Let's be careful on answers that line up with the opposing view here!

What does all this mean? That can be hard to see! But at least we have the concepts discussed down, so let's head to the answers and see what we can find.

Answer Explanation:
(Lines 16-19; Lines 41-43) When glass is cooled below its transition temperature, it "takes on" the properties of a solid. That must mean it doesn't have those properties above that temperature—and the alternative is molten or liquid glass. That would flow under its own weight. This would be enough to select this answer, but this is also backed up later on in the scientists' reasoning on why the common explanation for the thicker-bottomed medieval glass is wrong.

Key Takeaway:
Don't let science trip you up! As we can see from this question, the real issue being tested wasn't the science but the language and logic of it. The correct answer rests on you inferring that a change has two parts to it, and a transition from one to the other having an effect implies that changing back would reverse that effect.

Incorrect. (Line 10) The passage notes that glass atoms aren't arranged in a fixed crystalline structure, and it doesn't pose any hypotheticals as to what would happen if they were.