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Practice Test 3 - ACT Science

20 questions. Answer them in any order, then submit to see your score and every explanation.

  1. According to Figure 1, the voltmeter measures the potential difference across which component?
  2. A scientist claims that Strain B enzymes are "thermophilic" (heat-loving) compared to Strain A enzymes. Do the results in Figure 1 support this claim?
  3. In an experiment measuring reaction rates, a catalyst is used, but it's stored in a container with other chemicals. If contamination occurs, the measured reaction rate would most likely:
  4. A student measured the speed of a cart rolling down different ramp angles. Figure 1 plots cart speed versus ramp angle. Based on the scatter plot, which statement best describes the relationship between ramp angle and cart speed?
  5. In an experiment to measure the boiling point of water, a student records the temperature every minute until boiling is observed. The thermometer is not calibrated correctly and consistently reads 2°C higher than the actual temperature. Which factor is the most significant source of error in this procedure?
  6. Based on Figure 1, which labeled point is the epicenter of the earthquake?
  7. A survey recorded the number of hours students studied per week and their exam scores. Figure 2 shows a scatter plot of study hours versus exam scores. Which conclusion is most strongly supported by the data?
  8. Which statement about the model is best supported by Figure 1?
  9. Students tested whether an antacid tablet neutralizes stomach acid faster when crushed. Materials: 6 beakers, 100 mL of 0.10 M HCl per beaker, antacid tablets (same brand), mortar and pestle, pH probe, stirrer. Procedure: (1) In 3 beakers, add one whole tablet; in 3 beakers, add one tablet crushed to powder. (2) Stir all beakers at 300 rpm. (3) Record pH every 15 s for 5 min. (4) Define "neutralized" as pH reaching 4.0. Results: crushed tablets reached pH 4.0 in 75 s; whole tablets in 180 s. The primary purpose of this experiment was to:
  10. A study was conducted to examine the effect of exercise on mood improvement. Participants engaged in either aerobic or anaerobic exercise for 30 minutes daily. Mood was self-reported using a survey. Which factor introduces a confounding variable?
  11. A study examines the impact of sunlight on plant growth. Model 1 suggests plants grow faster with more sunlight due to increased photosynthesis. Model 2 suggests growth is limited by nutrient availability, not sunlight. Data shows plants exposed to more sunlight grew faster. Which model is best supported by the data?
  12. A student examines the effect of sugar type on cookie texture. The independent variable is sugar type, and the dependent variable is cookie texture score. Which factor introduces a confounding variable?
  13. A team of biologists investigated how different diets affect the growth rate of a species of fish. The type of diet was varied, and the growth rate was measured. Water quality and tank size were kept constant. What was the independent variable?
  14. Researchers examined how exercise intensity affects heart rate. Volunteers walked on a treadmill at four speeds: 2 km/h, 4 km/h, 6 km/h, and 8 km/h for 5 minutes each. The treadmill incline was kept at 0% and the room temperature was held at 21∘21^\circC. Heart rate (beats per minute) was recorded at the end of each 5-minute interval using the same monitor. In this experiment, the dependent variable is:
  15. An experiment was performed to study the effect of temperature on the solubility of a salt in water. The temperature of the water was varied, and the amount of salt dissolved was measured. The volume of water and type of salt remained the same throughout the experiment. Which factor was controlled in this experiment?
  16. In a study testing whether caffeine affects reaction time, participants' reaction times are measured before and after consuming caffeine. Which hypothesis is being tested?
  17. Which of the following variables was held constant in Study 2 but varied in Study 1?
  18. A public health team summarized flu vaccination in two age groups. Table A shows counts of vaccinated and unvaccinated people in a sample of adults ages 18–49. Table B shows percentages vaccinated and unvaccinated in a separate sample of adults ages 65+. Determine how the tables differ in both population and reporting format.
  19. Based on Figure 1, what is the length of the block?
  20. Which of the following statements best explains why there were no white-eyed males in Study 1?

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