Teacher Demonstration
Use the live model as a shared screen demonstration before students try their own predictions and observations.
Physics / Electricity and Magnetism
Variable Resistor
Explore Variable Resistor as an interactive EJS simulation for electricity and magnetism.
1. Watch or Launch
Launch the Interactive
Open the simulation, adjust the controls, and compare what changes on screen before answering the concept-check questions.
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2. Big Ideas
Key idea Measurement is a bridge between the physical world and a model. Good measurements require appropriate instruments, units, precision, uncertainty, and evidence-based reporting.
What Students Can Learn
- Choose a suitable measuring instrument.
- Read scales systematically.
- Use units and sensible significant figures.
- Discuss uncertainty and repeated readings.
Guiding Question
What is being measured, how is it read, and how reliable is the result?
3. Try the Investigation
Identify the Quantity
Decide whether the model is about length, time, mass, vector quantity, or data.
Use the Instrument or Display
Read the scale, graph, or numerical display carefully.
Record With Units
State the measurement with suitable unit and precision.
Evaluate Reliability
Discuss uncertainty, repeat readings, or possible errors.
4. Teacher Notes
Lesson Use
Use this resource to strengthen measurement habits: read carefully, record with units, and explain reliability.
Discussion Prompts
Ask: What instrument or display gives the evidence? What is the smallest meaningful reading? What could cause error?
Teaching Moves
Ask students to give the reading and a short uncertainty comment. This makes measurement more than just writing a number.
5. Concept Check
These questions are generated from the topic and the concept illustrated by the simulation. Use them after students have explored the model.
Concept Score
Correct first attempts build a streak and unlock higher point multipliers on this device.
0page points
0current streak
x1multiplier
0best streak
Answer each question once to build your streak.
1. What should come with a measured value?
2. Why choose a suitable instrument?
3. What does uncertainty remind us?
4. Why repeat a measurement?
5. What is a good measurement explanation?
Expert Challenge
Unlocks after 3 correct concept-check answers on this page.
1. In a bar-magnet field-line interactive, what should students use to infer field direction?
2. What feedback fits 'magnetic field lines start at one pole and stop in empty space'?
3. How should students compare two magnets in the model?
4. What should students infer from denser magnetic field lines?
5. What makes a magnetism answer expert-level?
7. Learning Pulse
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