Grade: 9-12

Estimated Time: 45–60 minutes

Materials: Computer with internet access and the Electric & Magnetic Field Energy simulation, student worksheet (this handout), graphing paper or spreadsheet software.

Part 1: Engage (Anchoring Phenomenon)

A team of engineers designing a magnetic docking system notices that two identical magnets sometimes require more work to separate than others, depending on how they are oriented and how far apart they start. Why does the effort required to move the magnets change with distance and orientation?

Ask: What questions do you have about how distance, polarity (or charge), and object magnitude affect the forces between objects and the energy stored in the field between them?

Write two questions below that you want to investigate using the simulation:

Part 2: Explore (Simulation Investigation)

Follow these steps and record your observations and data. Use the simulation controls: Interaction Type, Object 1 Magnitude (q₁ or m₁), Object 2 Magnitude (q₂ or m₂), and dragging Object 2 to change separation. Units used by the simulation: distances are displayed in pixels (px) and the Energy Meter shows a normalized stored-field energy (visual percent). Force is displayed qualitatively (Low / Medium / High) and a numeric distance is shown.

Part A — Qualitative exploration (10 minutes)

1. Open the simulation and select Electric (Opposite Charges).
2. Set q₁ = 5 and q₂ = 5 (default). Drag Object 2 slowly away from Object 1 and observe:
   • How do the Force Vectors (arrows) change in direction and length?
   • How does the Energy Meter change as you increase distance?
3. Repeat for Electric (Same Charges), Magnetic (Opposite Poles), and Magnetic (Same Poles).

Record one qualitative sentence for each interaction type describing how stored field energy changes as distance increases:

• Electric (Opposite Charges): ______________

• Electric (Same Charges): _______________

• Magnetic (Opposite Poles): ______________

• Magnetic (Same Poles): _______________

Part B — Quantitative investigation (25–30 minutes)

Design and carry out an investigation to determine how stored field energy depends on separation for one interaction type of your choice (electric or magnetic, choose either opposite or same). Use the following procedure as a starting point and adapt as needed.

Procedure (suggested):

1. Choose Interaction Type: ________
2. Fix q₁ = __ and q₂ = __ (choose integer magnitudes between 1 and 10).
3. Record the force level (Low / Medium / High), the energy-meter percent (estimate from the energy bar width), and the distance (px) for separations: 60, 100, 150, 200, 300 px. (If the simulation’s canvas limits prevent exact pixel values, record the displayed distance values.)
4. Repeat each measurement twice and compute the average stored energy percent.

Sample Data Table (CSV-ready):

distance_px,force_level,trial1_energy_percent,trial2_energy_percent,avg_energy_percent 60,,,, 100,,,, 150,,,, 200,,,, 300,,,,

Notes on units and measures:

• Distance: displayed as pixels (px). Use the numeric value shown on the simulation as Distance.
• Stored field energy: use the Energy Meter visual percent (estimate the percentage width of the bar; 0% = empty, 100% = full).
• Force: recorded qualitatively as Low / Medium / High when asked.

Part 3: Explain (Sensemaking)

Use your data from Part B to answer the following prompts. Support each answer with evidence from your measurements and reference changes in force and energy.

1. Describe how stored field energy changed as separation changed for your chosen interaction. Was the stored energy higher when objects were closer or farther apart? Explain why, referencing the direction of work required (push/pull) and the sign of the interaction.

2. Using the simulation’s qualitative force indicator and your observations of arrow length, explain how the force magnitude relates to separation.

3. Construct a verbal model that connects object magnitude (q₁ and q₂), separation, force, and stored field energy. Use the phrase “the energy stored in the field increases when …” in your response.

Part 4: Elaborate/Evaluate (Argumentation & Modeling)

Final deliverable (choose one):

• Option A — Written explanation (recommended): Write a 1–2 page explanation that includes (a) a clear claim about how stored field energy changes with distance for your chosen interaction; (b) evidence from your table (averages) and qualitative observations; and (c) reasoning that connects the evidence to your claim using the concept that work done against or by the field changes stored energy.

• Option B — Model sketch and oral explanation: Prepare a labeled diagram (or digital drawing) showing object positions, force vectors, and an annotated note describing energy changes. Present your model to the class and answer teacher questions.

Teacher checklist for grading:

• Includes an explicit claim answering whether stored energy increases or decreases with distance.
• Uses at least three data points from the table to support the claim.
• Provides reasoning that connects forces (direction and magnitude) to change in stored field energy.
• Includes a clear description of the chosen interaction type and magnitudes.

Extensions

• Investigate how changing q₁ and q₂ magnitudes affects the shape of the energy vs. distance relationship. Collect data for two additional magnitude pairs and compare.
• Compare electric opposite-charge behavior to magnetic opposite-pole behavior: do they show similar qualitative trends in stored energy vs. distance?

Teacher Notes & Alignment

Estimated time: 45–60 minutes (shorter if teacher provides pre-filled data table). Materials: simulation, student worksheet, graphing tools.

SEPs: Developing and Using Models, Planning and Carrying Out Investigations, Analyzing and Interpreting Data. DCIs: PS3.C Relationship Between Energy and Forces. CCCs: Cause and Effect.

Evidence statements (HS-PS3-5) used as success criteria:

• “Develop and use a model of two objects interacting through electric or magnetic fields to illustrate the forces between objects and the changes in energy of the objects due to the interaction.”
• Observable features: Students identify components, describe relationships between components including change in energy given initial and final positions, and determine whether energy stored in the field increased, decreased, or remained the same.

How student work demonstrates evidence statements:

• Students produce a model and explanation that identifies the two objects, the nature of interaction, the direction and relative magnitude of forces, and a qualitative determination of stored field energy change consistent with observations.