ACT Science: Interpret Experimental Results and Draw Conclusions

Step 1: Read the hypothesis and identify what the experimenter predicted. Step 2: Locate the independent variable (what changed) and the dependent variable (what was measured). Step 3: Examine the results table or graph to see what actually happened. Step 4: Compare prediction to outcome and draw a conclusion (did the data support the hypothesis or contradict it?). Most students fail because they skip step 4 and never actually state whether the hypothesis was supported, making it hard to answer the follow-up question.

Example: Hypothesis is "increasing temperature increases reaction rate." Independent variable: temperature (changed from 10°C to 50°C). Dependent variable: reaction rate (measured in moles/second). Results show reaction rate went from 2 to 8 moles/second as temperature rose. Conclusion: The hypothesis was supported; higher temperature led to faster reaction rate. This four-step sequence works on every experiment question.

Trap 1: Assuming the data supports the hypothesis when it actually contradicts it. Fix: Always compare the prediction to the actual outcome. Trap 2: Claiming a causal relationship when the data only shows correlation. Fix: Ask "Did the experimenter control all other variables?" Trap 3: Overgeneralizing results beyond the data shown. Fix: Only conclude what the data directly supports. Trap 4: Confusing the independent variable (what changed on purpose) with the dependent variable (what was measured as a result). Fix: Write "IV:" and "DV:" next to your work. Trap 5: Missing confounding variables that could explain the results. Always check whether the experiment controlled for other factors that might affect the outcome.

Example: If an experiment changes both temperature and light intensity while measuring plant growth, you can't say which variable caused the growth. The experiment is flawed.

Experiment 1: Hypothesis: "Sunlight increases photosynthesis rate." IV: sunlight (on vs. off). DV: oxygen production (measured). Results: Plants in sunlight produced 10 mL O2 per hour; plants in dark produced 1 mL O2 per hour. Your conclusion? Experiment 2: Hypothesis: "pH affects enzyme activity." IV: pH (varied from 4 to 10). DV: enzyme activity (measured). Results: Maximum activity at pH 7; less activity at pH 4 and pH 10. Conclusion? Experiment 3: Hypothesis: "Caffeine affects heart rate." IV: caffeine dose (0, 50, 100, 150 mg). DV: heart rate (measured). Results: Heart rate increased from 60 to 90 bpm as caffeine dose rose. Conclusion? For each, state clearly whether the hypothesis was supported or not, and cite the specific data that proves your answer.

Answers: Exp 1: Supported; sunlight increases O2 production. Exp 2: Supported; maximum activity at pH 7. Exp 3: Supported; higher caffeine = higher heart rate. If you struggled, redo the four-step method aloud and check that you matched IV, DV, and outcome correctly.

About 15-20% of ACT Science questions ask you to interpret experimental results or draw conclusions from data. These questions are predictable and don't require deep scientific knowledge; they just require careful reading and logic. Master the four-step method, avoid the five logic traps, and you'll unlock 3-4 reliable points per Science section.

Spend this week doing one practice experiment per day using the four-step method aloud. By test day, interpreting experiments will feel like a mechanical task instead of a reasoning puzzle.