- At recess, Carlos pulls a ball with a string across flat ground. He asks, "If I pull harder, will the ball move farther?" The ball starts at the same cone each time. What should students keep the same for a fair test?
Answer: Keep the same ball, string, and starting cone
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 pull on the ball while keeping other factors the same and measure the resulting distance moved. Choice B is correct because keeping the same ball, string, and starting cone controls variables, ensuring a fair test focused on force effects. Incorrect choices like A, C, and D fail because they introduce changes to objects or surfaces, which confounds results and indicates a misconception about maintaining constants. 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 pulling different weights, and watch for errors where multiple items are varied.
- On the playground, Chen pushes a swing from the same starting rest spot. He asks, "Does a harder push make the swing go higher?" He will push gently, then harder, and observe. What should Chen measure to answer his question?
Answer: How high the swing goes each time
This question assesses planning investigations to show force effects on motion (3-PS2-1). To test if harder pushes make swings go higher, students must identify the relevant measurement - the motion outcome of height. The correct answer (A) properly identifies measuring swing height as the way to collect evidence about how push force affects motion. The distractors (B, C, D) represent irrelevant observations that don't answer the investigation question, showing students often get distracted by interesting but unrelated features. Effective investigations require measuring exactly what the question asks about - if investigating height, measure height; if investigating distance, measure distance. Teachers should help students match measurements to questions using simple prompts like "What does the question ask? That's what we measure!" and practice with everyday examples.
- In class, Emma pushes the same book from the same start mark three times. She asks, "Does a harder push make the book move farther?" The book starts still each time. Why should students repeat the test?
Answer: To get more evidence and check the pattern
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 book while keeping other factors the same and measure the resulting distance traveled. Choice A is correct because repeating provides more evidence and verifies patterns, strengthening the investigation's reliability. Incorrect choices like B, C, and D fail because they propose changes or cessation of measuring, which weakens consistency and reflects a misconception about replication's role. 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 book slides, and watch for students who alter setups between trials.
- In class, Jamal pushes a toy car from the same tape line each time. He asks, "Does a harder push make the car move farther?" What should students change to test force and motion?
Answer: Change how hard they push the car
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 strength of the force applied, such as pushing harder or softer, while keeping all other variables the same and measuring the resulting motion, like how far the car travels. The correct choice, changing how hard they push the car, works because it isolates the effect of force strength, allowing students to collect evidence through a fair test and observe patterns in motion. Distractors like using a different toy car or changing the floor fail because they introduce multiple variables, leading to the misconception that the test is fair when it's not, as it confuses the cause of any observed changes. 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 testing ramp heights, and watch for common errors where students accidentally change multiple factors.
- Keisha pushes a marble on a ramp from the same marked line. She asks, "Do different push forces change how far it goes?" What should students keep the same for a fair test?
Answer: Keep the same ramp and starting line
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 ramp and starting line consistent, while changing the push force, and measuring the distance the marble travels. The correct choice, keeping the same ramp and starting line, works because it controls key variables for a fair test, enabling clear evidence collection on force's impact on motion. Distractors like changing ramp height or using different marbles fail because they introduce confounding factors, leading to the misconception that results are due to force alone. 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 ramp experiments, and watch for students altering setups mid-test.
- In the gym, Amir pushes a swing from the same starting spot. He asks, "Does a stronger push make the swing go higher?" The swing starts still each time. What should students measure to answer their question?
Answer: How high the swing goes after each push
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.
- Emma slides the same book on the same table from the same start line. She asks, "Does pushing harder make the book move farther?" She will push softly, then harder, and record results. What should Emma measure to answer her question?
Answer: How new the book looks
This question tests identifying relevant measurements in force and motion investigations (3-PS2-1). To answer whether pushing harder makes books move farther, students must recognize that distance is the key measurement. The correct answer (A) properly identifies measuring sliding distance as the way to collect evidence about the force-motion relationship being investigated. The distractors (B, C, D) represent irrelevant observations that don't provide data about the investigation question, showing how students often notice interesting but unrelated features. Effective investigations require measuring exactly what the question asks about - when investigating "farther," we measure distance, not appearance or environmental factors. Teachers should help students connect investigation questions to measurements using prompts like "The question says 'farther' so we measure distance" and practice with various question-measurement pairs.
- Sofia rolls a ball on the gym floor from the same tape line. She asks, "If I pull the ball back harder, will it roll farther?" She will pull back softly, then harder, and record results. What should Sofia measure to answer her question?
Answer: How shiny the ball looks
This question assesses planning investigations to show force effects on motion (3-PS2-1). To answer a question about how pull-back force affects rolling distance, students must identify what to measure - the motion outcome. The correct answer (B) properly identifies measuring rolling distance as the way to collect evidence about the force-motion relationship. The distractors (A, C, D) represent irrelevant observations that don't provide data about the investigation question, showing a common misconception where students focus on interesting but unrelated features. Effective investigations require measuring the specific outcome mentioned in the question - if asking about distance, measure distance; if asking about speed, measure speed. Teachers should help students connect investigation questions directly to what needs measuring, using simple examples like "If we ask 'Does it go farther?' we measure distance."
- Amir tests a swing by pushing from the same starting spot. He asks, "Does a harder push make the swing go higher?" What should students change to test force and motion?
Answer: Change how hard they push the swing
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.
- Emma slides the same book on a desk from one marked spot. She asks, "Do different surfaces need different push strengths?" What should students keep the same for a fair test?
Answer: Keep the same book and same starting spot
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.
- Yuki rolls a ball from the same tape line on the gym floor. She tests, "Will a harder pull back make the ball roll farther?" She pulls back softly and then harder. What should Yuki keep the same for a fair test?
Answer: Use the same ball and the same start line
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.
- Marcus slides a block on the same desk from the same tape line. He asks, "Does a harder push make it move faster?" The block starts still each time. What should students change to test how force affects motion?
Answer: How hard they push the block
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.
- In class, Maya slides a book on a smooth table from the same spot. She asks, "Do different surfaces need different push strength to move?" She will use the same book and start line each time. What should Maya keep the same for a fair test?
Answer: Keep the same book and starting point
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.
- Carlos pushes a toy car three times with a soft push. Then he pushes three times with a harder push from the same line. He asks, "Does a harder push make it move farther?" Why should Carlos repeat the test?
Answer: To change the starting line each time
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.
- In the gym, Keisha pushes a toy car from the same start line. She asks, "Does a harder push make the car move farther?" The car starts still each time. What should students keep the same for a fair test?
Answer: Use the same toy car and the same start line
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.
- Marcus rolls the same ball from one tape line in the gym. He asks, "Does a stronger pull make the ball roll farther?" What should students change to test force and motion?
Answer: Change how hard they pull the string
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 pull strength, keep the ball and starting line consistent, and measure the rolling distance to test force effects. The correct choice, changing how hard they pull the string, works because it isolates the force variable, allowing for a fair test and clear evidence of motion changes. Distractors like changing the ball's weight or starting line fail because they vary additional factors, causing the misconception that the test fairly assesses pull strength alone. 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 string-pull experiments, and watch for common errors in varying equipment.
- Maya uses a marble ramp and starts the marble at the same spot each time. She asks, "Do different pushes change how far the marble travels?" The marble starts still at the top. What should students do first?
Answer: Pick a start mark and place the marble there
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 marble while keeping other factors the same and measure the resulting distance traveled. Choice B is correct because picking a start mark and placing the marble there establishes a consistent setup, allowing for a fair test and proper evidence collection from the beginning. Incorrect choices like A, C, and D fail because they involve premature measuring, unnecessary changes, or opinions, which disrupt planning and show a misconception about initial steps in investigations. 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 setting up ramp tests, and watch for students who jump ahead without consistent starting points.
- In class, Sofia slides a book on the same table from the same start mark. She asks, "Does a harder push make the book move farther?" The book starts still each time. What should students measure to answer their question?
Answer: How far the book slides from the start mark
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 book while keeping other factors the same and measure the resulting distance slid. Choice A is correct because measuring how far the book slides directly captures the effect of force on motion, helping to collect relevant evidence for a fair comparison. Incorrect choices like B, C, and D fail because they focus on irrelevant aspects, such as pictures or sounds, which do not relate to motion changes and indicate a misconception about what data to gather. 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 measuring toy movements, and watch for students focusing on non-essential observations.
- Chen tests a toy car on the classroom floor with soft and hard pushes. The car starts at the same tape line and is still each time. He asks, "Does push strength change how far it moves?" Why should students repeat the test?
Answer: To use a different toy car each trial
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 repeating the test builds more trustworthy results by confirming patterns and reducing errors, ensuring reliable evidence. Incorrect choices like B, C, and D fail because they suggest altering variables or stopping measurements, which undermines consistency and reflects a misconception about the purpose of replication. 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 multiple rolls of a ball, and watch for students who skip repeats or change setups mid-test.
- Marcus pushes a swing from a stop in the same spot each time. He asks, "Does a harder push make the swing go higher?" He will push gently, then harder, and record. What should Marcus keep the same for a fair test?
Answer: Change the push strength and the swing chain
This question assesses planning controlled investigations about forces and motion (3-PS2-1). When testing if harder pushes make swings go higher, students must identify which variables to control for valid results. The correct answer (B) properly identifies keeping the same person swinging and starting from the same position as essential controls, ensuring only push force varies between trials. The distractors show common control errors: changing the test subject (A), changing multiple variables simultaneously (C), or varying starting conditions (D), all violating fair-test principles. Scientific investigations require controlling all variables except the one being tested to establish clear cause-and-effect relationships. Teachers should emphasize "same person, same start, different push" and have students practice identifying controls through hands-on activities where changing multiple things makes results confusing.
