What important physics idea is this question targeting?
The question is testing whether students know that energy increases as the force between the objects gets stronger. (I)
The task targets students’ ability to connect field-based interactions with both force and energy: specifically, that moving opposite charges closer increases force but decreases potential energy. (C)
The question targets how electric forces behave in charged systems and how energy is involved when positions change. (V)
Which answer best describes what student A's response indicates about their physics understanding?
The student is unclear about forces at a far distance — they think the balloon and hat only attract when close, which shows they don’t understand electrostatic forces fully. However, they can reason correctly from that incorrect reasoning. (I)
Student A appears to equate the strength of a force with the amount of energy — a common misconception. They are reasoning causally and consistently, but they don’t yet distinguish between force (interaction strength) and potential energy (stored energy based on configuration). (C)
The student is able to make connections between force, distance, and energy, and is beginning to integrate those ideas into their reasoning. (V)
Which of the following options would best support Student A in being able to correctly respond to this question?
I would set up a few different scenarios (gravitational, magnetic, electrostatic) and have students work in groups to make predictions about force and energy. Then we’d reflect on whether stronger forces always mean more stored energy — helping them break the overgeneralized ‘more force = more energy’ connection.” (C)
I would use our word wall in the class to keep track of definitions and equations. I would have them review the definitions and equations for electrostatic forces separately and then apply those to this scenario. (I)
I’d help the student explore how interactions vary with distance and support them in articulating how those changes impact system behavior. (V)
Student B's response:
Which answer best describes what student B's response indicates about their physics understanding?
This student clearly understands that energy is related to the amount of charge, and since the charges didn’t change, it makes sense that they said the energy stayed the same. They’re applying a solid idea — that if nothing is added to the system, the energy must be conserved. However, they have not used our formal definitions for energy or force. (I)
Student B correctly recognizes that the electric force increases with decreased distance, showing they understand the inverse relationship between force and separation in a field interaction. However, they incorrectly assume that potential energy stays the same just because the charges didn’t change, suggesting they conflate “amount of charge” with “amount of energy.” (C)
The student shows a developing awareness of how energy and force relate to configuration, but still need help connecting those ideas more precisely. (V)
Which of the following options would best support Student B in being able to correctly respond to this question?
I’d give the student two scenarios with the same charges at different distances and ask: ‘Which one would take more work to pull apart?’ This would help them understand that the farther-apart system stores more potential energy, even though the charge is the same — shifting their focus from what is charged to how it’s arranged. (C)
I’d have the student use an interactive simulation to explore how force changes with distance between charged objects. We’d graph the force versus distance and talk about what they notice as things get closer. This would help reinforce their understanding of electrostatic interactions and how distance affects force. (I)
I would pair up students to discuss their answers, and then ask them make precise distinctions between force, charge, and energy for an exit ticket. (V)