ACT Past Papers with Answers

Paper 6

ACT September 2023

Form G01 · Science Test · 40 questions

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Paper 6 · ACT September 2023 · Form G01 · Science Test

Based on Scientist 3’s viewpoint, which of the follow- ing quantities is approximately equal for the stars in an open cluster?

AMassBDiameterCAgeDTemperature

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Paper 6 · ACT September 2023 · Form G01 · Science Test

The stars in an open cluster are bound together by gravity. Scientist 3 supports the conclusion that the gravitational force of an open cluster is: indefinitely. the Sun. Sun. 39 GO ON TO THE NEXT PAGE. ACT-G01 4 4 Passage II A study was conducted to identify the properties of a type of sand being mined at a given site. Natural processes bring this sand to the mining site from 1 of 4 possible sources, all located within a few miles of the site: a river, inland dunes, underwater offshore dunes, or a beach to the north (see Figure 1). A second study examined sand from each of these possible sources to determine which of the sources supplies sand to the mining site. Figure 1 Study 1 Samples of the mined sand were collected at the mining site by taking a 2.5 cm diameter core 30 cm deep at 3 locations, 1 m apart. All organic matter, and all clay, silt, and gravel, were separated from the samples, leaving only sand-size particles (0.0625−2 mm in diameter). The col- oration of each particle and the average diameter of the particles were determined. A thin layer of the sand was glued to a glass slide, ground down until it was only 25 micrometers thick, and then examined under magnifica- tion using transmitted polarized light to determine the composition of each particle. The results are in Table 1. Study 2 The process of collecting and analyzing sand samples described in Study 1 was repeated at the 4 sites that were possible sources for the mined sand (see Table 2). north beach sand mining site offshore dunes inland dunes ocean river 2 km N 0 x 40 GO ON TO THE NEXT PAGE. ACT-G01 4 4 Table 1 Sample Average diameter (mm) Composition (% of all particles) Coloration (% of all particles) quartz K-feldspar plagioclase granite fragments amber white colorless dark Mined sand 0.4 48 17 14 7 17 75 7 1 41 GO ON TO THE NEXT PAGE. ACT-G01 4 4 Figure 1 and Tables 1 and 2 adapted from Rodney Combellick and Robert Osborne, “Sources and Petrology of Beach Sand from Southern Monterey Bay, California.” ©1977 by The Society of Economic Paleontologists and Mineralogists. Table 2 Sample Average diameter (mm) Composition (% of all particles) Coloration (% of all particles) quartz K-feldspar plagioclase granite fragments amber white colorless dark River sand 0.2 44 15 12 8 4 75 18 3 Underwater offshore dune sand 0.4 49 16 14 7 17 72 9 2 Inland dune sand 0.4 52 14 14 7 11 76 11 1 North beach sand 0.3 50 10 11 5 13 58 20 9

Astrong enough to keep the cluster togetherBtoo weak to keep the cluster together indefinitely.Cpresent only among the stars more massive thanDpresent only among the stars less massive than the

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Paper 6 · ACT September 2023 · Form G01 · Science Test

If sand is being supplied to the mining site from the inland dunes, one or both of which 2 erosion processes are most likely capable of moving the sand directly from the inland dunes to the mining site? Passage III A researcher performed 2 experiments to investigate seed germination in violet seeds. Experiment 1 On Day 0, the experimenter placed a piece of sterile filter paper inside each of 30 sterile Petri dishes, moistened each filter paper with the same aqueous solution, and placed 25 seeds on each filter paper. Next, 5 of these Petri dishes were placed in each of 6 growth chambers. No light was present in the growth chambers. Each chamber was maintained at 1 of 6 tempera- tures throughout the experiment. The percent of seeds that had germinated by Days 4, 8, 12, and 16 at each tempera- ture appears in Figure 1. Figure 1 Experiment 2 On Day 0, the experimenter placed a piece of sterile filter paper inside each of 30 sterile Petri dishes, moistened each filter paper with 1 of 6 aqueous solutions, and placed 25 seeds on each filter paper. Each aqueous solution had a different pH, and each was used to moisten the filter paper in 5 of the Petri dishes. All 30 Petri dishes were then placed in a growth chamber that was maintained at 20°C throughout the exper- iment. No light was present in the growth chamber. The percent of seeds that had germinated by Days 4, 8, 12, and 16 at each pH appears in Figure 2. Figure 2 Figures adapted from William C. Mitchell et al., “Analysis of Horned Violet, Viola cornuta L., Seed Germination.” ©2000 by the New Jersey Academy of Science. 100 95 90 85 80 75 70 65 60 55 50 45 40 10 15 20 25 30 35 temperature (°C) germination (%) Day 16 Day 12 Day 8 Day 4 Key 100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 pH germination (%) Day 16 Day 12 Day 8 Day 4 Key 42 GO ON TO THE NEXT PAGE. ACT-G01 4 4

AOcean waves and windBOcean waves and glaciersCRunning water and windDRunning water and glaciers

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Paper 6 · ACT September 2023 · Form G01 · Science Test

A student concluded that on Day 16 of Experiment 2 the seeds exposed to the most acidic solution had the lowest percent germination. Do the results support this conclusion? was observed in the seeds exposed to pH 2. was observed in the seeds exposed to pH 12. was observed in the seeds exposed to pH 2. was observed in the seeds exposed to pH 12. 43 GO ON TO THE NEXT PAGE. ACT-G01 4 4 Passage IV In the following experiments, a student studied some properties of inductors and capacitors, devices used to store electrical energy. Experiment 1 The student constructed an electrical circuit (see Figure 1) containing a 6 V battery, a switch, a 10 ohm resistor, a 50 H (henry, a unit of inductance) inductor, and an ammeter (a device used to measure the amount and direction [+ or −] of an electrical current). Figure 1 She closed the switch at time = 0.0 sec and immedi- ately began recording the current over time. The results are shown in Table 1. Experiment 2 She replaced the inductor in the electrical circuit with one having a different inductance. She closed the switch and 10.0 sec later recorded the electrical current. She repeated these steps using various inductors (see Table 2). Experiment 3 The student charged a capacitor using the circuit shown in Figure 2. Figure 2 Next, using the inductor from Experiment 1 and the charged capacitor, she assembled the circuit shown in Figure 3. Figure 3 She closed the switch at time = 0.0 sec and recorded the current in the circuit over time (see Table 3). She determined from the data in Table 3 that the period of this circuit (twice the time between successive zeros of the current) was 4.0 sec. Experiment 4 Using the procedures from Experiment 3 and various capacitors, the student studied how the period of the circuit in Figure 3 varied with capacitance (see Table 4). ammeter inductor resistor battery switch A Table 1 Time (sec) Current (amp) Table 2 Inductance (H) Current (amp) 10 30 50 70 capacitor A A Table 3 Time (sec) Current (amp) Table 4 Capacitance (μF)* Period (sec) 2,050 2.0 4,100 2.8 8,200 4.0 16,400 5.7 *μF (microfarad) is a unit of capacitance. 44 GO ON TO THE NEXT PAGE. ACT-G01 4 4

AYes; on Day 16, the lowest percent germinationBYes; on Day 16, the lowest percent germinationCNo; on Day 16, the lowest percent germinationDNo; on Day 16, the lowest percent germination 0.0 1.0 5.0 10.0 20.0 30.0 +0.00 +0.11 +0.38 +0.52 +0.59 +0.60 +0.60 +0.58 +0.52 +0.46 0.0 1.0 2.0 3.0 4.0 5.0 0.00 −0.08 0.00 +0.08 0.00 −0.08

Form G01 · Science Test · 40 questions

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