Science Passages: Reading & Science Tips

Natural-science reading passages plus ACT Science strategy for data and experiments.

Key Takeaways

• Reading format: 36 questions in 40 minutes, four passage sets of about nine questions, four choices each. Natural science is one of the four families.
• No outside science needed. Every answer is supported by the passage itself.
• Map paragraphs by role: phenomenon, puzzle, method, result, interpretation, caveat.
• Terms are defined in context. Use appositives, "called," "known as," examples, and contrasts.
• Follow cause-and-effect chains and watch for answers that skip a link or reverse the direction.
• Match the passage's caution. Suggests, preliminary, under laboratory conditions, and associated with all limit what you can conclude.
• Author's attitude is usually measured. "Interested but cautious" beats "dismissive" or "fully convinced" unless the text is extreme.

Key Takeaways

• Science format: optional, 40 questions in 40 minutes, four choices; reported separately and not part of the composite.
• Three passage formats: Data Representation, Research Summaries, Conflicting Viewpoints.
• Figure first: title, axes or headings, units, key, overall trend, in about 15 seconds.
• Look-up vs reverse look-up: find the value in the right column, then read across. Never copy digits into the wrong column.
• Greatest value is not greatest change. Compute differences; size of a change ignores its direction.
• Name the pattern: direct, inverse, peak, levels off. Two inversely related variables make a mirror image.
• Convert units before comparing.

Worked Examples

<details> <summary><b>Example 1: A Reading-style study in prose</b></summary>

A marine biologist suspected that a common snail avoids rock pools where crabs are present, even when it cannot see them. She filled twelve identical tanks with seawater. Six tanks received water that had previously held a crab; the other six received plain seawater. She placed ten snails in each tank and, after one hour, counted how many had climbed above the waterline.

Question: What was the purpose of the six tanks with plain seawater?

Solution:

1. Build the mini-table. Changed: water with or without crab scent. Measured: snails above the waterline. Same: tanks, snail number, time.
2. The plain-seawater tanks have no crab scent, so they are the control.
3. They show how many snails climb out without any crab signal, so a higher count in crab-scented tanks can be credited to the scent. They were not a second treatment or a way to test vision.

</details> <details> <summary><b>Example 2: Which trials isolate the variable?</b></summary>

Question: Which two trials show the effect of cart mass alone?

Solution:

1. Mass alone means everything else must match.
2. Trials 2 and 3: height 40 cm both, surface tile both, mass 200 vs 400 g. ✅
3. The distance barely changes (180 vs 178 cm), so mass had little effect. Trials 3 and 4 isolate surface instead, and Trials 1 and 2 isolate height.

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Worked Examples

<details> <summary><b>Example 1: Conflicting viewpoints</b></summary>

Introduction: A small island's lizards have longer back legs today than lizards on the mainland where the population originated about 60 years ago.

Scientist 1: The island has few trees and many open rocks. Lizards with longer legs run faster on open ground and escape predators, so over generations, long-legged lizards left more offspring.

Scientist 2: The longer legs do not reflect inherited differences at all. Young lizards that grow up running on rocks simply develop longer legs, just as muscles grow with use. Offspring raised on the mainland would have normal legs.

Question: Which finding would support Scientist 2 but NOT Scientist 1?

Solution:

1. S1 says legs changed because long-legged lizards reproduced more (an inherited change). S2 says legs grow longer with use during each lizard's life.
2. A finding that fits S2 only: island lizard eggs hatched and raised on the mainland grew normal-length legs. If the trait were inherited, these lizards should keep long legs, so this undercuts S1.
3. A finding like "long-legged lizards escape predators faster" supports S1, not S2. "The island has many rocks" is in both accounts, so it supports neither over the other.

</details> <details> <summary><b>Example 2: Linking two tables</b></summary>

Table 1: Altitude and air temperature on a mountain trail

Table 2: Air temperature and a beetle's walking speed

Question: About how fast would the beetle walk at 1,500 m?

Solution:

1. Table 1: 1,500 m → 15 °C. Temperature is the bridge.
2. Table 2: 15 °C is halfway between 14 °C (2.6 cm/s) and 16 °C (3.2 cm/s).
3. Halfway between 2.6 and 3.2 is 2.9 cm/s. Trap: reading "15" as a speed, or using 1,500 to look up Table 2 directly.

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Worked Examples

<details> <summary><b>Example 1: Building a Reading plan</b></summary>

Situation: On practice tests, a student finishes the first three Reading passages in 33 minutes and guesses on most of the fourth.

Solution:

1. Target: about 10 minutes per passage, so 30 minutes for three. She is 3 minutes over by the end of passage 3.
2. Fix with checkpoints: 10, 20, and 30 minutes. If she reaches minute 10 with two questions left on passage 1, she guesses, marks them, and moves on.
3. Trim the first read: a paragraph map ("P1 puzzle, P2 method, P3 result, P4 caveat") instead of rereading dense sentences until they feel clear.
4. Result: the fourth passage gets its full 10 minutes, which is worth far more than the two marked questions cost.

</details> <details> <summary><b>Example 2: Reading an error log</b></summary>

Situation: After a timed Science section, a student missed 12 questions: 5 unanswered when time ran out, 3 from wrong units, 2 from conflicting viewpoints, and 2 from rushed look-ups.

Solution:

1. Biggest category: time, 5 of 12.
2. Plan: a per-passage cap with skip-and-return, plus question-first scanning on the last passage.
3. Second priority: units, 3 of 12. Add a five-second "circle the units" step to the figure-first routine.
4. Not the plan: memorizing science facts. None of the 12 misses came from missing outside knowledge.

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Worked Examples

<details> <summary><b>Example 1: Interpolate or extrapolate?</b></summary>

Question A: Estimate the pressure at 1,500 m.

• 1,500 m is between 1,000 m and 2,000 m, so the pressure is between 90 and 79 kPa. Halfway: about 84.5 kPa.

Question B: If the trend continues, is the pressure at 4,000 m more likely about 62 kPa or about 81 kPa?

• Each 1,000 m lowers pressure by 11, 11, then 9 kPa: steady decrease, slightly shrinking. Another drop of about 8 kPa gives about 62 kPa. A value of 81 kPa would mean pressure rose with elevation, reversing the trend.

</details> <details> <summary><b>Example 2: Eliminate the traps</b></summary>

A survey of 20 city blocks found that blocks with more street trees had lower summer sidewalk temperatures. No trees were planted or removed during the survey.

Which conclusion is best supported?

• Planting trees on a block will lower its sidewalk temperature. ❌ Correlation as cause: nothing was changed, so the survey cannot show cause.
• Trees are the only factor that controls sidewalk temperature. ❌ Overclaiming: no other factors were studied.
• Blocks with the fewest trees reached the highest temperatures ever recorded in the city. ❌ Beyond the data: no city records were compared.
• Blocks with more street trees tended to have cooler sidewalks. ✅ Matches an observational study exactly.

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Worked Example: One Question, Every Skill

<details> <summary><b>Example: Linking two experiments through a shared trial</b></summary>

Setup: In Experiment 1, students measured how far a paper airplane flew with wings of 10, 15, and 20 cm at a launch angle of 10°: 6.2 m, 8.0 m, and 7.1 m. In Experiment 2, they kept the wings at 15 cm and changed the launch angle to 5°, 10°, and 15°: 7.4 m, 8.0 m, and 6.5 m.

Question: Starting from the 15 cm, 10° design, which single change shortened the flight more: switching to 20 cm wings, or raising the angle to 15°?

Solution:

1. Find the shared trial. 15 cm at 10° appears in both experiments, and both report 8.0 m. That is the baseline.
2. Change one factor at a time from the baseline. Wings to 20 cm: 8.0 → 7.1 m, a drop of 0.9 m. Angle to 15°: 8.0 → 6.5 m, a drop of 1.5 m.
3. Compare: raising the angle shortened the flight more.
4. Trap check: the longest flight in either experiment (8.0 m) is not the question. And the data cannot predict a 20 cm, 15° airplane, because no trial changed both factors.

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