Three Conclusions, One Paragraph
Ms. Rivera's class reads this paragraph: "When volunteers replaced the asphalt around Lincoln Elementary's south playground with turf and twelve young maples, they measured surface temperatures at noon for three weeks. Bare asphalt reached 128°F; shaded turf stayed near 89°F. Recess monitors reported fewer students sitting out with headaches. The district facilities office notes that the maples will not cast full shade for six to eight years and that the measurements covered a single summer." Three students state conclusions. Ana: "The new shade made the playground cooler." Ben: "Replacing asphalt at every district school will end heat illness." Cara: "Lincoln's playground will stay cool from now on."
1. Evaluate all three conclusions against the paragraph. Which is best supported, and what specifically makes each of the others overreach?
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Ana is closest, but even her claim is not fully supported. The paragraph reports two changes made at once - turf and maples - and then compares bare asphalt (128°F) with shaded turf (89°F). Because the surface material and the shade changed together, the paragraph cannot show that shade caused the drop; turf alone might account for part of it.
Ben overreaches on two fronts. The evidence comes from one playground at one school, so nothing supports "every district school," and "end heat illness" is a stronger outcome than "fewer students sitting out with headaches" from recess monitors, which is not a medical measure.
Cara overreaches on time. The facilities office says full shade is six to eight years away, so "stay cool from now on" ignores the text's own limit. The safest conclusion is limited and hedged: replacing asphalt with turf and planting trees was followed by much lower noon surface temperatures at this one site during one summer.
2. Name the single additional measurement that would most strengthen the paragraph's implied claim, and explain why the six-to-eight-year detail matters to a reader drawing an inference.
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Best addition: unshaded turf measured at the same noon times. That gives a third condition (turf without shade) and lets a reader separate the effect of the surface material from the effect of shade. Without it, the 128°F-to-89°F gap stays confounded. Adding measurements from a second summer or another school would help generalization, but it would not fix the confound.
Why the timeline matters: the maples are not yet doing the work the paragraph implies they will eventually do. A reader who infers "shade solved the problem" must notice that today's shade is partial. The correct inference is provisional: the change is promising now, and the effect attributed to trees specifically cannot be measured until the canopy fills in. The detail also signals that any benefit may grow - or may not, which the text never promises.