Question 42·Hard·Command of Evidence

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Archaeologists studying unglazed water jars found at an ancient settlement noticed that the jars contain different amounts of temper, a material added to clay that can create tiny channels in a fired vessel. To investigate the channels' function, researchers made low-, moderate-, and high-porosity replicas with identical dimensions, filled them with equal quantities of water at the same temperature, and placed them under the same conditions. The researchers proposed that moderate porosity offered a practical compromise: compared with low porosity, it substantially increased evaporative cooling, whereas increasing porosity from moderate to high caused much greater water loss but little additional cooling.

Which finding, if true, would most directly support the researchers' proposal?

A finding question with several comparisons tests whether evidence supports every part of a claim. Read the proposal and split it into parts, naming the groups and what’s being measured. Then predict what each part would need to show, including how large or small a change should be. With numbers, compare the changes between groups rather than reading each value alone. A finding can support one part and still fail another.

Hints

Hint 1
Look at the proposal after the experiment description. Separate what it says about cooling from what it says about water loss.
Hint 2
Which pair of porosity levels does each part of the proposal compare?
Hint 3
Subtract the moderate jar’s values from the high jar’s values for both cooling and water loss. Does each change agree with the size of the change the proposal predicts?

Step-by-step

Test both comparisons
Step 1
Split the proposal
The proposal calls moderate porosity a practical compromise, so we need evidence for both parts of that claim. What makes it a compromise? Moving from low to moderate must add substantial cooling, while moving from moderate to high must bring a large water cost for a small cooling gain.
Step 2
Measure the changes
The water began at the same temperature, so a larger temperature decrease means more cooling. How do we measure changes between jars? Subtract their values. For water loss, subtracting one percentage from another gives the change in percentage points.
Step 3
Set aside partial matches
Which findings miss part of the proposal? With 2%, 7%, and 8% water loss, the rise from moderate to high is only 1 percentage point, which doesn’t show much greater water loss. With 1, 1.5, and 5 degrees of cooling, low to moderate adds only 0.5 degree, but moderate to high adds 3.5 degrees, which reverses the proposed pattern. With 1, 4, and 7 degrees, each step adds 3 degrees, which doesn’t show little additional cooling at high porosity.
Step 4
Find the full match
The finding with 2%, 7%, and 24% water loss shows a 17-percentage-point rise from moderate to high, so the extra water cost is large. How much cooling does that buy? It buys only 0.5 degree, from 5 to 5.5, while low to moderate adds 4 degrees, from 1 to 5. That supports the proposed practical compromise. Choice D.

Lessons that teach this

SAT Reading: Information and IdeasAdvancedCoreFindings that support or weaken a claim

Question 42·Hard·Command of Evidence

Strategy

Hints

Step-by-step

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Strategy

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