This question tests planning fair investigations about forces and motion (3-PS2-1). When investigating how different surfaces affect push strength needed, students must keep all non-tested variables constant for valid results. The correct answer (C) identifies keeping the same book and starting point as essential controls, ensuring only the surface variable changes between trials. The distractors show common errors: changing multiple variables (A), inconsistent starting conditions (B), or using subjective measures (D) instead of controlled testing. Fair tests require changing only what you're testing while keeping everything else exactly the same, allowing clear cause-and-effect conclusions. Teachers should use the mantra "same book, same spot, different surface" and have students practice identifying controls versus variables in various investigation scenarios.

This question assesses planning fair tests about forces and motion (3-PS2-1). When investigating how pull-back force affects rolling distance, students must identify which factors to keep constant for valid results. The correct answer (A) properly identifies keeping the same ball and start line as essential controls, ensuring only the pull-back force changes between trials. The distractors represent common fair-test violations: changing the object tested (B), varying starting conditions (C), or changing the testing surface (D), all of which would make results meaningless. Fair investigations require changing only the factor being tested while keeping all other conditions identical. Teachers should use the phrase "same ball, same line, different pull" and have students practice identifying what stays the same versus what changes in various investigations.

This question aligns with the skill 3-PS2-1, which involves planning an investigation to show how forces affect the motion of an object. In this investigation, students change the strength of the push on the block while keeping other factors the same and measure the resulting speed or distance. Choice A is correct because altering how hard they push isolates the force variable, enabling a fair test of its effect on motion. Incorrect choices like B, C, and D fail because they suggest changing constants like surface or size, which introduces confounding factors and shows a misconception about variable control. A key principle in such investigations is to change only one variable, like force strength, keep others constant, measure the outcome like speed, and repeat trials for accuracy. To teach this, educators can use the phrase 'change one thing, keep others the same' to guide students. Additionally, practice with simple examples like sliding objects, and watch for students who mistakenly vary multiple elements.

This question aligns with the skill 3-PS2-1, which involves planning an investigation to show how forces affect the motion of an object. In this investigation, students change the strength of the push on the toy car while keeping other factors the same and measure the resulting distance traveled. Choice A is correct because using the same toy car and start line ensures that only the push strength affects the motion, allowing for a fair test and reliable evidence collection. Incorrect choices like B, C, and D fail because they introduce unnecessary variables, such as changing the car or spot, which confounds the results and reflects a misconception about controlling variables. A key principle in such investigations is to change only one variable, like force strength, keep others constant, measure the outcome like distance, and repeat trials for accuracy. To teach this, educators can use the phrase 'change one thing, keep others the same' to guide students. Additionally, practice with simple examples like testing ramp heights, and watch for common errors where students accidentally change multiple factors.

This question aligns with the skill 3-PS2-1, which involves planning an investigation to show how forces affect the motion of an object. In this investigation, students change the strength of the push on the swing while keeping other factors the same and measure the resulting height achieved. Choice A is correct because measuring how high the swing goes directly assesses the force's impact on motion, providing meaningful evidence. Incorrect choices like B, C, and D fail because they emphasize irrelevant details like color or appearance, which do not measure motion and reflect a misconception about data relevance. A key principle in such investigations is to change only one variable, like force strength, keep others constant, measure the outcome like height, and repeat trials for accuracy. To teach this, educators can use the phrase 'change one thing, keep others the same' to guide students. Additionally, practice with simple examples like pendulum swings, and watch for students distracted by non-motion factors.

This question assesses planning systematic investigations about forces and motion (3-PS2-1). Before testing how object weight affects push strength needed, students must establish consistent starting conditions for fair comparison. The correct answer (B) identifies marking a start line as the essential first step, ensuring all pushes begin from the same position for valid results. The distractors represent procedural errors: measuring before establishing conditions (A), changing variables during testing (C), or using subjective measures (D) instead of systematic setup. Proper investigations begin with establishing controlled conditions - marking positions, gathering materials, and planning measurements - before collecting any data. Teachers should model investigation setup using "First we mark, then we test" and have students practice preparing simple investigations with proper controls.

This question tests understanding of planning investigations to show how forces affect motion (3-PS2-1). When investigating how force strength affects motion, students must change only the force variable while keeping everything else constant to make a fair test. The correct answer (A) identifies changing the push strength as the proper variable to test, which directly addresses the investigation question about harder pushes. The distractors represent common student errors of wanting to change multiple variables (B, C, D) instead of isolating just the force variable. In scientific investigations, we change one thing at a time, keep all other factors the same, and measure the results to draw valid conclusions. Teachers should emphasize the phrase "change one, keep others the same" and have students practice identifying what to change versus what to keep constant in simple investigations.

This question tests understanding of repeated trials in force and motion investigations (3-PS2-1). When testing if harder pushes make objects move farther, students must understand why multiple trials strengthen conclusions. The correct answer (B) identifies that repetition provides more evidence and reveals patterns, making results more reliable than single observations. The distractors show misconceptions about repetition's purpose: thinking it changes the object (A), varies conditions (C), or affects the force itself (D) rather than improving data quality. Scientific investigations use repeated trials to confirm patterns aren't accidents and to identify consistent relationships between variables. Teachers should explain "We repeat to be sure" and demonstrate how multiple trials reveal clearer patterns, using examples where first tries might be flukes but repeated results show true relationships.

This question aligns with the skill 3-PS2-1, which involves planning an investigation to show how forces affect the motion of an object. In this investigation, students should change the force strength, such as pushing the swing harder or softer, while keeping other elements like the swing and starting spot constant, and measuring the height achieved. The correct choice, changing how hard they push the swing, works because it directly tests the force variable, allowing students to gather evidence through a fair test and link force to motion changes. Distractors like changing the swing or student fail because they alter multiple variables, causing the misconception that the test isolates force effects when it doesn't. A key principle in such investigations is to change only one thing at a time, keep everything else the same, measure the outcome accurately, and repeat trials for reliability. To teach this effectively, educators can use the phrase 'change one thing, keep others the same' to guide students. Additionally, practice with simple examples like playground equipment tests, and watch for common errors where students vary the equipment unintentionally.

This question aligns with the skill 3-PS2-1, which involves planning an investigation to show how forces affect the motion of an object. In this investigation, students should keep the book and starting spot constant, while changing surfaces, applying forces, and measuring required push strengths. The correct choice, keeping the same book and same starting spot, works because it controls essential variables for a fair test, helping students collect accurate evidence on surface effects. Distractors like using a new book or changing push and surface together fail because they introduce uncontrolled changes, leading to the misconception that results are reliable despite multiple variables. A key principle in such investigations is to change only one thing at a time, keep everything else the same, measure the outcome accurately, and repeat trials for reliability. To teach this effectively, educators can use the phrase 'change one thing, keep others the same' to guide students. Additionally, practice with simple examples like surface sliding tests, and watch for students mixing variables like object types.