- After rubbing a balloon on hair, a student tries to make it stick to a wall. To investigate what affects the electric force, which variable is best to change on purpose (independent variable) while keeping others the same?
Answer: The distance between the balloon and the wall when first bringing it close
This question tests understanding of how to ask good investigable questions about electric forces by identifying variables that can be tested and formulating specific, testable questions. Good investigable questions about electric forces should: (1) focus on one specific variable at a time (charge amount, distance, material type, object size), (2) be testable with available materials (balloons, plastic rods, electroscopes, Van de Graaff generators available in schools), (3) have measurable outcomes (count paper pieces attracted, measure distance leaves separate, observe repulsion strength), and (4) ask "how does X affect Y?" format where X is variable you change (independent) and Y is force-related effect you measure (dependent). Poor questions are too broad ("What is electricity?"), not testable with simple materials, or don't focus on force specifically. For distance investigation: A good investigable question is "How does distance between the charged balloon and the wall affect the electric force?"—this is specific (tests distance variable), testable (can bring balloon to different starting distances and observe sticking), measurable (measure sticking time or success at each distance), and focused on one variable (distance, keeping charge constant). Choice C is correct because it correctly identifies an appropriate variable that affects electric force and can be investigated as the independent variable (distance changed on purpose). Choice B is wrong because it suggests a variable that doesn't actually affect electric force, or isn't relevant to the observation. Generating investigable questions from observations: (1) observe electric force phenomenon (balloon sticks to wall), (2) notice what could vary (distance, charge amount), (3) pick one variable to focus on, (4) formulate question: "How does [that variable] affect [the force strength or effect]?", (5) check: can I change that variable (independent), can I measure the effect (dependent), do I have needed materials?, (6) if yes to all, it's a good investigable question; for example, "How does starting distance affect sticking time?" is excellent for middle school.
- A student charges a balloon by rubbing it on hair, then slowly moves it away from a pile of tiny paper pieces. They want to measure how electric force changes with distance. What is the best dependent variable (what they should measure/observe) to show force strength in this setup?
Answer: How many paper pieces jump up and stick to the balloon at each distance
This question tests understanding of how to ask good investigable questions about electric forces by identifying variables that can be tested and formulating specific, testable questions. Good investigable questions about electric forces should: (1) focus on one specific variable at a time (charge amount, distance, material type, object size), (2) be testable with available materials (balloons, plastic rods, electroscopes, Van de Graaff generators available in schools), (3) have measurable outcomes (count paper pieces attracted, measure distance leaves separate, observe repulsion strength), and (4) ask "how does X affect Y?" format where X is variable you change (independent) and Y is force-related effect you measure (dependent). For distance investigation: The student wants to measure how electric force changes with distance, so they need a dependent variable that directly shows force strength - counting how many paper pieces jump up and stick to the balloon at each distance provides a clear, quantifiable measure of the attractive force (more pieces = stronger force, fewer pieces = weaker force). Choice A is correct because it properly identifies a measurable outcome that directly indicates electric force strength - the number of paper pieces attracted is proportional to the force strength, making it an excellent dependent variable for this investigation. Choice B (mass of balloon) doesn't change and isn't what you measure to show force; Choice C (brand of paper) is a control variable that should stay constant, not what you measure; Choice D (student's hair color) is completely unrelated to measuring electric force strength. Generating investigable questions from observations: (1) observe electric force phenomenon (charged balloon attracts paper), (2) identify what to change (distance), (3) identify what to measure that shows force (paper pieces attracted), (4) formulate investigation: change distance systematically, count papers at each distance, (5) check: does counting papers show force strength (yes - more papers = stronger force), (6) this makes "number of paper pieces attracted" the correct dependent variable for investigating how distance affects electric force.
- A student can rub different rods (plastic, glass, and rubber) with the same cloth and then bring each rod near small paper pieces to see how strongly they attract. What is the best investigable question about factors affecting electric force in this situation?
Answer: Which rod material (plastic, glass, or rubber) produces the strongest attraction of paper pieces after being rubbed the same way?
This question tests understanding of how to ask good investigable questions about electric forces by identifying variables that can be tested and formulating specific, testable questions. Good investigable questions about electric forces should: (1) focus on one specific variable at a time (charge amount, distance, material type, object size), (2) be testable with available materials (balloons, plastic rods, electroscopes, Van de Graaff generators available in schools), (3) have measurable outcomes (count paper pieces attracted, measure distance leaves separate, observe repulsion strength), and (4) ask "how does X affect Y?" format where X is variable you change (independent) and Y is force-related effect you measure (dependent). For material comparison: "Which rod material (plastic, glass, or rubber) produces the strongest attraction of paper pieces after being rubbed the same way?" is a good question because it's testable (can rub each material the same amount and same way), measurable (bring each near paper pieces and count how many attracted), and compares a clear variable (material type) while controlling others (same rubbing method, same distance). Choice A is correct because it formulates a specific, testable question focused on one variable (material type) and properly evaluates which material produces the strongest electric force by measuring a clear outcome (number of paper pieces attracted). Choice B "What is the best material in the world?" is too vague and not specific to electric forces; Choice C about counting electrons exactly is not measurable with middle school equipment; Choice D about why paper is made from trees is completely unrelated to investigating electric forces. Generating investigable questions from observations: (1) observe that different materials can be charged by rubbing, (2) identify the variable to test (material type: plastic vs glass vs rubber), (3) keep other variables constant (same rubbing method, same distance to papers), (4) formulate comparison question: "Which material produces strongest attraction?", (5) plan to measure by counting attracted papers for each material, (6) this creates a clear investigation comparing how material type affects electric force strength.
- A student rubs a balloon on their hair and then holds it near small paper pieces. The paper pieces jump up and stick to the balloon. The student wants to design an investigation about what affects the strength of the electric force between the balloon and the paper. Which question is the most specific and testable with these materials?
Answer: How does the distance between the charged balloon and the paper pieces affect how many paper pieces are attracted?
This question tests understanding of how to ask good investigable questions about electric forces by identifying variables that can be tested and formulating specific, testable questions. Good investigable questions about electric forces should: (1) focus on one specific variable at a time (charge amount, distance, material type, object size), (2) be testable with available materials (balloons, plastic rods, electroscopes, Van de Graaff generators available in schools), (3) have measurable outcomes (count paper pieces attracted, measure distance leaves separate, observe repulsion strength), and (4) ask "how does X affect Y?" format where X is variable you change (independent) and Y is force-related effect you measure (dependent). Poor questions are too broad ("What is electricity?"), not testable with simple materials, or don't focus on force specifically. For distance investigation: A good investigable question is "How does distance between two charged objects affect the strength of electric force between them?"—this is specific (tests distance variable), testable (can move charged balloon closer to or farther from wall and observe whether it sticks better or falls off), measurable (can measure actual distances: 1 cm, 5 cm, 10 cm and observe force effect at each), and focused on one variable (distance, keeping charge amount and objects constant). Choice B is correct because it formulates a specific, testable question focused on one variable (distance) with clear independent (distance) and dependent (number of paper pieces attracted) variables. Choice A formulates a question that's asking for explanation (why?) rather than investigation of variable relationship (how does X affect Y?); Choice C asks a question that's too broad or vague and doesn't specify what to investigate or what to measure; Choice D suggests investigating multiple variables simultaneously (charge amount, distance, and balloon size all at once), making it not a focused investigation. Generating investigable questions from observations: (1) observe electric force phenomenon (balloon sticks to wall, hair stands up, papers attracted), (2) notice what could vary (charge amount, distance, materials, object size), (3) pick one variable to focus on, (4) formulate question: "How does [that variable] affect [the force strength or effect]?", (5) check: can I change that variable (independent), can I measure the effect (dependent), do I have needed materials?, (6) if yes to all, it's a good investigable question; if no, refine or choose different variable. Examples from electric force observations: see balloon stick to wall → question: "How does distance from wall affect how long balloon stays stuck?"; see Van de Graaff make hair stand up → question: "How does the charge amount (voltage setting) affect how high hair stands?"; see rubbed rod attract papers → question: "How does the number of rubs (charging time) affect how many papers are attracted?"—all are specific (one variable), testable (can manipulate variable), and measurable (count papers, measure time, observe height), making them excellent investigable questions for middle school science investigations.
- A student wants to compare which materials create stronger static electric forces when rubbed. They have a plastic rod, a glass rod, and a rubber rod, plus small paper bits to attract. Which question is best for this investigation?
Answer: Which rod material (plastic, glass, or rubber) attracts the most paper bits after being rubbed the same way?
This question tests understanding of how to ask good investigable questions about electric forces by identifying variables that can be tested and formulating specific, testable questions. Good investigable questions about electric forces should: (1) focus on one specific variable at a time (charge amount, distance, material type, object size), (2) be testable with available materials (balloons, plastic rods, electroscopes, Van de Graaff generators available in schools), (3) have measurable outcomes (count paper pieces attracted, measure distance leaves separate, observe repulsion strength), and (4) ask "how does X affect Y?" format where X is variable you change (independent) and Y is force-related effect you measure (dependent). Poor questions are too broad ("What is electricity?"), not testable with simple materials, or don't focus on force specifically. For material comparison: "Which rod material (plastic, glass, or rubber) attracts the most paper bits after being rubbed the same way?" is a good question because it's testable (rub each the same and test), measurable (count bits), and compares a clear variable (material type) while controlling others (same rubbing, distance). Choice A is correct because it formulates a specific, testable question focused on one variable (material type). Choice B is wrong because it formulates a question that's not testable with simple materials or doesn't focus on force specifically. Generating investigable questions from observations: (1) observe electric force phenomenon (rods attract paper), (2) notice what could vary (material type), (3) pick one variable to focus on, (4) formulate question: "How does [that variable] affect [the force strength or effect]?", (5) check: can I change that variable (independent), can I measure the effect (dependent), do I have needed materials?, (6) if yes to all, it's a good investigable question; for example, compare materials by counting attracted bits.
- A student writes this investigation question after rubbing a balloon on hair: "Does static electricity work?" Which revision makes it more specific and testable for measuring electric force strength?
Answer: How does rubbing the balloon more times affect how long the balloon stays stuck to the wall?
This question tests understanding of how to ask good investigable questions about electric forces by identifying variables that can be tested and formulating specific, testable questions. Good investigable questions about electric forces should: (1) focus on one specific variable at a time (charge amount, distance, material type, object size), (2) be testable with available materials (balloons, plastic rods, electroscopes, Van de Graaff generators available in schools), (3) have measurable outcomes (count paper pieces attracted, measure distance leaves separate, observe repulsion strength), and (4) ask "how does X affect Y?" format where X is variable you change (independent) and Y is force-related effect you measure (dependent). The original question "Does static electricity work?" is too vague and asks for a yes/no answer rather than investigating how a variable affects force strength - the revision "How does rubbing the balloon more times affect how long the balloon stays stuck to the wall?" transforms it into a specific, testable question that investigates how charge amount (controlled by rubbing times) affects force strength (measured by sticking time). Choice B is correct because it properly revises the vague question into one that asks "how does X affect Y?" format with clear independent variable (number of rubs/charge amount) and dependent variable (time balloon stays stuck/force strength), making it specific and testable. Choice A "What is static electricity?" is still too broad and asks for explanation rather than investigation; Choice C "Why does the balloon stick?" asks for explanation rather than testing variable effect; Choice D "Is electricity important?" is completely off-topic and not about investigating electric forces. Generating investigable questions from observations: (1) start with vague observation (static electricity "works"), (2) identify specific phenomenon (balloon sticks to wall), (3) pick measurable variable (rubbing times = charge amount), (4) pick measurable outcome (sticking time = force strength), (5) formulate: "How does rubbing times affect sticking time?", (6) this revision makes the question specific, testable, and focused on investigating how one variable affects electric force strength.
- A student writes this question after seeing hair stand up near a Van de Graaff generator: "How does the voltage setting on the generator affect how much a person's hair stands up?" Which statement best explains why this is an investigable question?
Answer: It is investigable because it changes one variable (voltage setting) and measures an observable effect (hair standing up).
This question tests understanding of how to ask good investigable questions about electric forces by identifying variables that can be tested and formulating specific, testable questions. Good investigable questions about electric forces should: (1) focus on one specific variable at a time (charge amount, distance, material type, object size), (2) be testable with available materials (balloons, plastic rods, electroscopes, Van de Graaff generators available in schools), (3) have measurable outcomes (count paper pieces attracted, measure distance leaves separate, observe repulsion strength), and (4) ask "how does X affect Y?" format where X is variable you change (independent) and Y is force-related effect you measure (dependent). Poor questions are too broad ("What is electricity?"), not testable with simple materials, or don't focus on force specifically. For charge amount investigation: The question "How does the voltage setting on the generator affect how much a person's hair stands up?" is investigable—you can vary voltage (charge amount), measure hair height, using school equipment. Choice B is correct because it properly evaluates the question as good because it's specific, testable, and measurable, changing one variable with observable effect. Choice C is wrong because it incorrectly claims the question includes every variable, but it focuses on one. Generating investigable questions from observations: (1) observe electric force phenomenon (hair stands up), (2) notice what could vary (voltage setting), (3) pick one variable to focus on, (4) formulate question: "How does [that variable] affect [the force strength or effect]?", (5) check: can I change that variable (independent), can I measure the effect (dependent), do I have needed materials?, (6) if yes to all, it's a good investigable question; for example, measure hair height at different voltages.
- A student observes: when a charged balloon is held very close to a wall, it sticks strongly; when held farther away, it may not stick at all. Which investigation best tests the effect of distance on electric force strength while keeping other factors the same?
Answer: Use the same balloon and same rubbing time, then test sticking/attraction at measured distances (e.g., 1 cm, 3 cm, 5 cm)
This question tests understanding of how to ask good investigable questions about electric forces by identifying variables that can be tested and formulating specific, testable questions. Good investigable questions about electric forces should: (1) focus on one specific variable at a time (charge amount, distance, material type, object size), (2) be testable with available materials (balloons, plastic rods, electroscopes, Van de Graaff generators available in schools), (3) have measurable outcomes (count paper pieces attracted, measure distance leaves separate, observe repulsion strength), and (4) ask "how does X affect Y?" format where X is variable you change (independent) and Y is force-related effect you measure (dependent). Poor questions are too broad ("What is electricity?"), not testable with simple materials, or don't focus on force specifically. For distance investigation: A good investigable question is "How does distance between two charged objects affect the strength of electric force between them?"—this is specific (tests distance variable), testable (can move charged balloon closer to or farther from wall and observe whether it sticks better or falls off), measurable (can measure actual distances: 1 cm, 5 cm, 10 cm and observe force effect at each), and focused on one variable (distance, keeping charge amount and objects constant). Choice B is correct because it correctly identifies an appropriate variable that affects electric force and can be investigated by controlling others while changing distance. Choice A suggests investigating multiple variables simultaneously; Choice C changes multiple variables at once; Choice D asks a question that's not testable with simple materials and is dangerous. Generating investigable questions from observations: (1) observe electric force phenomenon (balloon sticks to wall, hair stands up, papers attracted), (2) notice what could vary (charge amount, distance, materials, object size), (3) pick one variable to focus on, (4) formulate question: "How does [that variable] affect [the force strength or effect]?", (5) check: can I change that variable (independent), can I measure the effect (dependent), do I have needed materials?, (6) if yes to all, it's a good investigable question; if no, refine or choose different variable. Examples from electric force observations: see balloon stick to wall → question: "How does distance from wall affect how long balloon stays stuck?"; see Van de Graaff make hair stand up → question: "How does the charge amount (voltage setting) affect how high hair stands?"; see rubbed rod attract papers → question: "How does the number of rubs (charging time) affect how many papers are attracted?"—all are specific (one variable), testable (can manipulate variable), and measurable (count papers, measure time, observe height), making them excellent investigable questions for middle school science investigations.
- A student writes this investigation question after seeing a rubbed balloon attract paper: "How does rubbing time and distance and wall material affect electric force?" Which change would make the question more testable and focused?
Answer: Change it to: "How does the distance between the charged balloon and the paper affect the number of paper pieces attracted?"
This question tests understanding of how to ask good investigable questions about electric forces by identifying variables that can be tested and formulating specific, testable questions. Good investigable questions about electric forces should: (1) focus on one specific variable at a time (charge amount, distance, material type, object size), (2) be testable with available materials (balloons, plastic rods, electroscopes, Van de Graaff generators available in schools), (3) have measurable outcomes (count paper pieces attracted, measure distance leaves separate, observe repulsion strength), and (4) ask "how does X affect Y?" format where X is variable you change (independent) and Y is force-related effect you measure (dependent). Poor questions are too broad ("What is electricity?"), not testable with simple materials, or don't focus on force specifically. For distance investigation: A good investigable question is "How does distance between two charged objects affect the strength of electric force between them?"—this is specific (tests distance variable), testable (can move charged balloon closer to or farther from wall and observe whether it sticks better or falls off), measurable (can measure actual distances: 1 cm, 5 cm, 10 cm and observe force effect at each), and focused on one variable (distance, keeping charge amount and objects constant). Choice B is correct because it properly evaluates the question as good because it's specific, testable, and measurable, focusing on one variable (distance). Choice A changes to a broad question not focused on variables; Choice C formulates a question that's asking for explanation (why?) rather than investigation; Choice D asks yes/no question without testing variable effect. Generating investigable questions from observations: (1) observe electric force phenomenon (balloon sticks to wall, hair stands up, papers attracted), (2) notice what could vary (charge amount, distance, materials, object size), (3) pick one variable to focus on, (4) formulate question: "How does [that variable] affect [the force strength or effect]?", (5) check: can I change that variable (independent), can I measure the effect (dependent), do I have needed materials?, (6) if yes to all, it's a good investigable question; if no, refine or choose different variable. Examples from electric force observations: see balloon stick to wall → question: "How does distance from wall affect how long balloon stays stuck?"; see Van de Graaff make hair stand up → question: "How does the charge amount (voltage setting) affect how high hair stands?"; see rubbed rod attract papers → question: "How does the number of rubs (charging time) affect how many papers are attracted?"—all are specific (one variable), testable (can manipulate variable), and measurable (count papers, measure time, observe height), making them excellent investigable questions for middle school science investigations.
- A student wants to test whether more charge creates a stronger electric force using a balloon and paper pieces. Which plan best changes only the amount of charge on the balloon?
Answer: Rub the balloon for 5 s, 10 s, and 20 s each trial, and each time hold it the same distance from the paper
This question tests understanding of how to ask good investigable questions about electric forces by identifying variables that can be tested and formulating specific, testable questions. Good investigable questions about electric forces should: (1) focus on one specific variable at a time (charge amount, distance, material type, object size), (2) be testable with available materials (balloons, plastic rods, electroscopes, Van de Graaff generators available in schools), (3) have measurable outcomes (count paper pieces attracted, measure distance leaves separate, observe repulsion strength), and (4) ask "how does X affect Y?" format where X is variable you change (independent) and Y is force-related effect you measure (dependent). Poor questions are too broad ("What is electricity?"), not testable with simple materials, or don't focus on force specifically. For charge amount investigation: The question "Does the amount of charge on an object affect the electric force strength?" is investigable—you can test it by varying charge amount (rub balloon 5 times vs 10 times vs 20 times to produce different charge amounts, or use Van de Graaff at different voltage settings), then measuring force effects (how many paper pieces attracted, how strongly balloon sticks to wall, how far apart electroscope leaves separate), and comparing results to see if more charge correlates with stronger force. Choice A is correct because it correctly identifies an appropriate variable that affects electric force and can be investigated by changing rubbing time (charge) while controlling distance. Choice B changes distance instead of charge; Choice C suggests investigating multiple variables simultaneously; Choice D asks for guesses rather than measurable data. Generating investigable questions from observations: (1) observe electric force phenomenon (balloon sticks to wall, hair stands up, papers attracted), (2) notice what could vary (charge amount, distance, materials, object size), (3) pick one variable to focus on, (4) formulate question: "How does [that variable] affect [the force strength or effect]?", (5) check: can I change that variable (independent), can I measure the effect (dependent), do I have needed materials?, (6) if yes to all, it's a good investigable question; if no, refine or choose different variable. Examples from electric force observations: see balloon stick to wall → question: "How does distance from wall affect how long balloon stays stuck?"; see Van de Graaff make hair stand up → question: "How does the charge amount (voltage setting) affect how high hair stands?"; see rubbed rod attract papers → question: "How does the number of rubs (charging time) affect how many papers are attracted?"—all are specific (one variable), testable (can manipulate variable), and measurable (count papers, measure time, observe height), making them excellent investigable questions for middle school science investigations.
- After rubbing a balloon on hair, a student presses it against a wall and it sticks for a while before slowly falling off. The student wants to test one variable that might change how strongly the balloon sticks. Which is the best independent variable to change in a simple investigation?
Answer: How long the balloon is rubbed on hair before placing it on the wall
This question tests understanding of how to ask good investigable questions about electric forces by identifying variables that can be tested and formulating specific, testable questions. Good investigable questions about electric forces should: (1) focus on one specific variable at a time (charge amount, distance, material type, object size), (2) be testable with available materials (balloons, plastic rods, electroscopes, Van de Graaff generators available in schools), (3) have measurable outcomes (count paper pieces attracted, measure distance leaves separate, observe repulsion strength), and (4) ask "how does X affect Y?" format where X is variable you change (independent) and Y is force-related effect you measure (dependent). Poor questions are too broad ("What is electricity?"), not testable with simple materials, or don't focus on force specifically. For charge amount investigation: The question "Does the amount of charge on an object affect the electric force strength?" is investigable—you can test it by varying charge amount (rub balloon 5 times vs 10 times vs 20 times to produce different charge amounts, or use Van de Graaff at different voltage settings), then measuring force effects (how many paper pieces attracted, how strongly balloon sticks to wall, how far apart electroscope leaves separate), and comparing results to see if more charge correlates with stronger force. Choice B is correct because it correctly identifies an appropriate variable that affects electric force and can be investigated (rubbing time affects charge amount, which is testable by changing duration and observing sticking strength). Choice A proposes variable that doesn't actually affect electric force, or isn't relevant to the observation; Choice C suggests a variable unrelated to electric force; Choice D asks yes/no question without testing variable effect: "Do charged objects attract?" doesn't investigate how any variable affects force. Generating investigable questions from observations: (1) observe electric force phenomenon (balloon sticks to wall, hair stands up, papers attracted), (2) notice what could vary (charge amount, distance, materials, object size), (3) pick one variable to focus on, (4) formulate question: "How does [that variable] affect [the force strength or effect]?", (5) check: can I change that variable (independent), can I measure the effect (dependent), do I have needed materials?, (6) if yes to all, it's a good investigable question; if no, refine or choose different variable. Examples from electric force observations: see balloon stick to wall → question: "How does distance from wall affect how long balloon stays stuck?"; see Van de Graaff make hair stand up → question: "How does the charge amount (voltage setting) affect how high hair stands?"; see rubbed rod attract papers → question: "How does the number of rubs (charging time) affect how many papers are attracted?"—all are specific (one variable), testable (can manipulate variable), and measurable (count papers, measure time, observe height), making them excellent investigable questions for middle school science investigations.
- A student uses a plastic rod rubbed with cloth to attract tiny pieces of paper. They want to test how the amount of charge affects electric force strength. Which investigable question matches that goal?
Answer: How does rubbing the rod for different amounts of time affect the number of paper pieces it can pick up?
This question tests understanding of how to ask good investigable questions about electric forces by identifying variables that can be tested and formulating specific, testable questions. Good investigable questions about electric forces should: (1) focus on one specific variable at a time (charge amount, distance, material type, object size), (2) be testable with available materials (balloons, plastic rods, electroscopes, Van de Graaff generators available in schools), (3) have measurable outcomes (count paper pieces attracted, measure distance leaves separate, observe repulsion strength), and (4) ask "how does X affect Y?" format where X is variable you change (independent) and Y is force-related effect you measure (dependent). Poor questions are too broad ("What is electricity?"), not testable with simple materials, or don't focus on force specifically. For charge amount investigation: The question "How does rubbing the rod for different amounts of time affect the number of paper pieces it can pick up?" is investigable—you can test it by varying rubbing time (to produce different charge amounts), then measuring force effects (count paper pieces), and comparing results to see if more rubbing correlates with stronger force. Choice A is correct because it formulates a specific, testable question focused on one variable (charge amount via rubbing time). Choice D is wrong because it asks yes/no question without testing variable effect: "Will the rod attract paper?" doesn't investigate how any variable affects force. Generating investigable questions from observations: (1) observe electric force phenomenon (rod attracts paper), (2) notice what could vary (rubbing time, distance), (3) pick one variable to focus on, (4) formulate question: "How does [that variable] affect [the force strength or effect]?", (5) check: can I change that variable (independent), can I measure the effect (dependent), do I have needed materials?, (6) if yes to all, it's a good investigable question; for example, "How does rubbing time affect papers attracted?" is specific and measurable.
- A student plans this experiment: rub a balloon 10 times, then 20 times, then 30 times, and each time count how many paper pieces stick to it from a fixed distance. Which investigation question does this experiment best answer?
Answer: How does the amount of charge (changed by rubbing more times) affect the strength of the electric force (measured by number of paper pieces attracted)?
This question tests understanding of how to ask good investigable questions about electric forces by identifying variables that can be tested and formulating specific, testable questions. Good investigable questions about electric forces should: (1) focus on one specific variable at a time (charge amount, distance, material type, object size), (2) be testable with available materials (balloons, plastic rods, electroscopes, Van de Graaff generators available in schools), (3) have measurable outcomes (count paper pieces attracted, measure distance leaves separate, observe repulsion strength), and (4) ask "how does X affect Y?" format where X is variable you change (independent) and Y is force-related effect you measure (dependent). The experiment design clearly tests how charge amount (varied by rubbing 10, 20, 30 times) affects electric force strength (measured by counting paper pieces attracted), with distance held constant - this perfectly matches the question "How does the amount of charge affect the strength of the electric force?" Choice A is correct because it asks "how does X affect Y?" format with clear independent variable (amount of charge changed by rubbing more times) and dependent variable (strength of electric force measured by number of paper pieces attracted), perfectly matching the described experiment. Choice B about speed of electricity is not what this experiment tests; Choice C "Why do walls exist?" is philosophical and unrelated to the experiment; Choice D about paper pieces having feelings is nonsensical and not a scientific question. This experiment demonstrates good investigation design: (1) one variable changed systematically (rubbing times = charge amount), (2) clear measurement of effect (count papers), (3) controls in place (same distance each trial), (4) multiple trials (10, 20, 30 rubs) to see pattern, (5) results will show if more charge (more rubs) creates stronger force (more papers attracted), answering the investigation question about how charge amount affects force strength.
- A student observes that a charged balloon attracts paper from farther away right after rubbing, but less well a few minutes later. Which refined investigable question best fits this observation and stays focused on one variable?
Answer: How does time after charging the balloon affect the maximum distance from which it can attract paper bits?
This question tests understanding of how to ask good investigable questions about electric forces by identifying variables that can be tested and formulating specific, testable questions. Good investigable questions about electric forces should: (1) focus on one specific variable at a time (charge amount, distance, material type, object size), (2) be testable with available materials (balloons, plastic rods, electroscopes, Van de Graaff generators available in schools), (3) have measurable outcomes (count paper pieces attracted, measure distance leaves separate, observe repulsion strength), and (4) ask "how does X affect Y?" format where X is variable you change (independent) and Y is force-related effect you measure (dependent). Poor questions are too broad ("What is electricity?"), not testable with simple materials, or don't focus on force specifically. A good investigable question for this observation is "How does time after charging the balloon affect the maximum distance from which it can attract paper bits?"—this is specific (tests time variable, relating to charge decay), testable (measure attraction distance at different times), measurable (record distances), and focused on one variable. Choice B is correct because it formulates a specific, testable question focused on one variable (time). Choice C is wrong because it suggests investigating multiple variables simultaneously (time, distance, paper size), making it not a focused investigation. Generating investigable questions from observations: (1) observe electric force phenomenon (attraction weakens over time), (2) notice what could vary (time after charging), (3) pick one variable to focus on, (4) formulate question: "How does [that variable] affect [the force strength or effect]?", (5) check: can I change that variable (independent), can I measure the effect (dependent), do I have needed materials?, (6) if yes to all, it's a good investigable question; for example, "How does time affect attraction distance?" is excellent.
- After rubbing a balloon on hair, a student sticks it to a wall. Sometimes it sticks longer than other times. If the student wants to test how amount of charge affects electric force, which independent variable should they change on purpose?
Answer: The number of times they rub the balloon on their hair
This question tests understanding of how to ask good investigable questions about electric forces by identifying variables that can be tested and formulating specific, testable questions. Good investigable questions about electric forces should: (1) focus on one specific variable at a time (charge amount, distance, material type, object size), (2) be testable with available materials (balloons, plastic rods, electroscopes, Van de Graaff generators available in schools), (3) have measurable outcomes (count paper pieces attracted, measure distance leaves separate, observe repulsion strength), and (4) ask "how does X affect Y?" format where X is variable you change (independent) and Y is force-related effect you measure (dependent). For charge amount investigation: The student can test how charge amount affects electric force by varying the number of times they rub the balloon (rub balloon 5 times vs 10 times vs 20 times to produce different charge amounts), then measuring force effects (how long balloon sticks to wall, how strongly it attracts), and comparing results to see if more rubbing (more charge) correlates with stronger force. Choice B is correct because it correctly identifies an appropriate variable that affects electric force and can be investigated - the number of times they rub the balloon directly controls the amount of charge built up through friction, making it the proper independent variable for testing how charge amount affects force strength. Choice A (color of balloon) doesn't affect charge amount or electric force; Choice C (day of the week) is completely unrelated to electric forces; Choice D (whether they like the experiment) is about personal preference, not a physical variable affecting electric force. Generating investigable questions from observations: (1) observe electric force phenomenon (balloon sticks to wall sometimes longer), (2) notice what could vary (charge amount through rubbing), (3) pick that variable to focus on, (4) formulate question: "How does number of rubs affect sticking time?", (5) check: can I control rubs (yes), can I measure time (yes), do I have materials (yes), (6) all yes means rubbing times is the correct independent variable to investigate charge amount's effect on electric force.
- A student writes: "Does a charged rod attract paper?" The teacher says this is not a strong investigable question about factors affecting force strength. Which revision makes it more specific and testable?
Answer: How does changing the distance between the charged rod and the paper affect the number of paper pieces attracted?
This question tests understanding of how to ask good investigable questions about electric forces by identifying variables that can be tested and formulating specific, testable questions. Good investigable questions about electric forces should: (1) focus on one specific variable at a time (charge amount, distance, material type, object size), (2) be testable with available materials (balloons, plastic rods, electroscopes, Van de Graaff generators available in schools), (3) have measurable outcomes (count paper pieces attracted, measure distance leaves separate, observe repulsion strength), and (4) ask "how does X affect Y?" format where X is variable you change (independent) and Y is force-related effect you measure (dependent). Poor questions are too broad ("What is electricity?"), not testable with simple materials, or don't focus on force specifically. For distance investigation: A good revision is "How does changing the distance between the charged rod and the paper affect the number of paper pieces attracted?"—this is specific (tests distance), testable (vary distance and count), measurable, and focused on force strength. Choice B is correct because it formulates a specific, testable question focused on one variable (distance) and improves the original yes/no to "how does X affect Y?". Choice A is wrong because it creates question asking for explanation (why?) rather than investigation of variable relationship (how does X affect Y?). Generating investigable questions from observations: (1) observe electric force phenomenon (rod attracts paper), (2) notice what could vary (distance, charge), (3) pick one variable to focus on, (4) formulate question: "How does [that variable] affect [the force strength or effect]?", (5) check: can I change that variable (independent), can I measure the effect (dependent), do I have needed materials?, (6) if yes to all, it's a good investigable question; for example, revise to test distance effect on attraction.
- A student rubs a balloon on their hair and notices the balloon can attract small paper bits from a desk. Which investigable question is most specific and testable for finding what affects the strength of the electric force?
Answer: How does the distance between the charged balloon and the paper bits affect how many paper bits are attracted?
This question tests understanding of how to ask good investigable questions about electric forces by identifying variables that can be tested and formulating specific, testable questions. Good investigable questions about electric forces should: (1) focus on one specific variable at a time (charge amount, distance, material type, object size), (2) be testable with available materials (balloons, plastic rods, electroscopes, Van de Graaff generators available in schools), (3) have measurable outcomes (count paper pieces attracted, measure distance leaves separate, observe repulsion strength), and (4) ask "how does X affect Y?" format where X is variable you change (independent) and Y is force-related effect you measure (dependent). Poor questions are too broad ("What is electricity?"), not testable with simple materials, or don't focus on force specifically. A good investigable question for this observation is "How does the distance between the charged balloon and the paper bits affect how many paper bits are attracted?"—this is specific (tests distance variable), testable (can move charged balloon closer to or farther from paper bits and observe attraction), measurable (count the number of bits at each distance), and focused on one variable (distance, keeping charge and other factors constant). Choice B is correct because it formulates a specific, testable question focused on one variable (distance) and asks "how does X affect Y?" format with clear independent and dependent variables. Choice A is wrong because it formulates a question that's too broad and asks for an explanation (why?) rather than investigation of variable relationship (how does X affect Y?). Generating investigable questions from observations: (1) observe electric force phenomenon (balloon attracts paper bits), (2) notice what could vary (distance, charge amount), (3) pick one variable to focus on, (4) formulate question: "How does [that variable] affect [the force strength or effect]?", (5) check: can I change that variable (independent), can I measure the effect (dependent), do I have needed materials?, (6) if yes to all, it's a good investigable question; for example, from balloon attracting paper, "How does distance affect number of bits attracted?" is specific, testable, and measurable.
- A student brings a charged rod near an electroscope, and the electroscope leaves spread apart (diverge). The student wants to answer the question: "How does the distance from the charged rod affect electric force strength?" What is the best dependent variable to measure?
Answer: The angle or amount of separation between the electroscope leaves
This question tests understanding of how to ask good investigable questions about electric forces by identifying variables that can be tested and formulating specific, testable questions. Good investigable questions about electric forces should: (1) focus on one specific variable at a time (charge amount, distance, material type, object size), (2) be testable with available materials (balloons, plastic rods, electroscopes, Van de Graaff generators available in schools), (3) have measurable outcomes (count paper pieces attracted, measure distance leaves separate, observe repulsion strength), and (4) ask "how does X affect Y?" format where X is variable you change (independent) and Y is force-related effect you measure (dependent). Poor questions are too broad ("What is electricity?"), not testable with simple materials, or don't focus on force specifically. You could investigate by charging a balloon, placing it at various distances from paper pieces, and counting how many it attracts at each distance, or by measuring how far charged electroscope leaves separate when charged rod is brought to different distances. Choice B is correct because it correctly identifies the dependent variable that measures the effect of electric force strength (leaf separation indicates force magnitude). Choice A proposes a variable that doesn't actually affect electric force; Choice C suggests a variable unrelated to the force measurement; Choice D is irrelevant to the investigation. Generating investigable questions from observations: (1) observe electric force phenomenon (balloon sticks to wall, hair stands up, papers attracted), (2) notice what could vary (charge amount, distance, materials, object size), (3) pick one variable to focus on, (4) formulate question: "How does [that variable] affect [the force strength or effect]?", (5) check: can I change that variable (independent), can I measure the effect (dependent), do I have needed materials?, (6) if yes to all, it's a good investigable question; if no, refine or choose different variable. Examples from electric force observations: see balloon stick to wall → question: "How does distance from wall affect how long balloon stays stuck?"; see Van de Graaff make hair stand up → question: "How does the charge amount (voltage setting) affect how high hair stands?"; see rubbed rod attract papers → question: "How does the number of rubs (charging time) affect how many papers are attracted?"—all are specific (one variable), testable (can manipulate variable), and measurable (count papers, measure time, observe height), making them excellent investigable questions for middle school science investigations.
- A student uses a Van de Graaff generator. When they touch it, their hair stands up because the hairs repel each other. The student wants an investigable question about what affects the repulsion force. Which question is best?
Answer: How does changing the generator setting (amount of charge) affect how far the hairs spread apart?
This question tests understanding of how to ask good investigable questions about electric forces by identifying variables that can be tested and formulating specific, testable questions. Good investigable questions about electric forces should: (1) focus on one specific variable at a time (charge amount, distance, material type, object size), (2) be testable with available materials (balloons, plastic rods, electroscopes, Van de Graaff generators available in schools), (3) have measurable outcomes (count paper pieces attracted, measure distance leaves separate, observe repulsion strength), and (4) ask "how does X affect Y?" format where X is variable you change (independent) and Y is force-related effect you measure (dependent). Poor questions are too broad ("What is electricity?"), not testable with simple materials, or don't focus on force specifically. For charge amount investigation: The question "Does the amount of charge on an object affect the electric force strength?" is investigable—you can test it by varying charge amount (rub balloon 5 times vs 10 times vs 20 times to produce different charge amounts, or use Van de Graaff at different voltage settings), then measuring force effects (how many paper pieces attracted, how strongly balloon sticks to wall, how far apart electroscope leaves separate), and comparing results to see if more charge correlates with stronger force. Choice A is correct because it formulates a specific, testable question focused on one variable (charge amount via generator setting) with clear independent and dependent variables (setting and hair spread distance). Choice B asks a question that's not testable with simple materials and is opinion-based; Choice C is too broad and unrelated to electric force; Choice D asks for exact unmeasurable details not feasible with school equipment. Generating investigable questions from observations: (1) observe electric force phenomenon (balloon sticks to wall, hair stands up, papers attracted), (2) notice what could vary (charge amount, distance, materials, object size), (3) pick one variable to focus on, (4) formulate question: "How does [that variable] affect [the force strength or effect]?", (5) check: can I change that variable (independent), can I measure the effect (dependent), do I have needed materials?, (6) if yes to all, it's a good investigable question; if no, refine or choose different variable. Examples from electric force observations: see balloon stick to wall → question: "How does distance from wall affect how long balloon stays stuck?"; see Van de Graaff make hair stand up → question: "How does the charge amount (voltage setting) affect how high hair stands?"; see rubbed rod attract papers → question: "How does the number of rubs (charging time) affect how many papers are attracted?"—all are specific (one variable), testable (can manipulate variable), and measurable (count papers, measure time, observe height), making them excellent investigable questions for middle school science investigations.
- A student rubs a balloon on hair 5 times, then 20 times, and each time counts how many paper bits the balloon can lift. What factor affecting electric force strength is the student most directly testing?
Answer: Amount of charge on the balloon (changed by rubbing more)
This question tests understanding of how to ask good investigable questions about electric forces by identifying variables that can be tested and formulating specific, testable questions. Good investigable questions about electric forces should: (1) focus on one specific variable at a time (charge amount, distance, material type, object size), (2) be testable with available materials (balloons, plastic rods, electroscopes, Van de Graaff generators available in schools), (3) have measurable outcomes (count paper pieces attracted, measure distance leaves separate, observe repulsion strength), and (4) ask "how does X affect Y?" format where X is variable you change (independent) and Y is force-related effect you measure (dependent). Poor questions are too broad ("What is electricity?"), not testable with simple materials, or don't focus on force specifically. For charge amount investigation: The student is varying rubbing times (5 vs 20) to change charge amount and measuring paper bits lifted, directly testing how charge affects force strength. Choice B is correct because it correctly identifies the variable being tested (amount of charge). Choice C is wrong because it proposes variable that doesn't actually affect electric force, or isn't relevant to the observation. Generating investigable questions from observations: (1) observe electric force phenomenon (balloon lifts paper), (2) notice what could vary (rubbing times for charge), (3) pick one variable to focus on, (4) formulate question: "How does [that variable] affect [the force strength or effect]?", (5) check: can I change that variable (independent), can I measure the effect (dependent), do I have needed materials?, (6) if yes to all, it's a good investigable question; for example, "How does rubbing time affect bits lifted?" is measurable.
