Physics: CASTLE (Circuits) Storyline

CASTLE:  Capacitor Aided System for Teaching and Learning Electricity

The CASTLE curriculum emphasizes circuits because they provide settings for hands-on inquiry that are intensely interesting for students with varied learning styles and are well suited to step-by-step model building. Teachers report that the CASTLE activities foster self-confidence and enthusiasm for physics, and that the uniqueness of these activities can “level the playing field” for a heterogeneous class. Field testing research has shown that these activities raise student confidence levels — dramatically so for females. These materials were adapted from the original CASTLE curriculum with the permission of Mel Steinberg and the CASTLE Project.

Unit 1 -Closed Loop Model

1. Identify situations in which a bulb will and will not light.
2. Identify the differences between conductors and insulators.
3. Trace continuous conducting path in conductors and through the internal parts of a light bulb.
4. Give evidence based on compass deflections to support one-way direction of flow.
5. Identify and apply the definition of conventional current.

Unit 2: Charge Flow and Sources of Charge Model

1. Represent simple circuits with schematic diagrams.
2. Identify the structure/parts of a capacitor.
3. Indicate the direction of charge flow throughout a circuit during capacitor charging and discharging.
4. Identify the places in a circuit where mobile charge originates.
5. Indicate the origin of conventional charge flow in a complete circuit.
6. Compare the amount of charge stored in different capacitors.

OPTIONAL – Identify, describe, and explain energy flow in a variety of circuits and with a variety of charge moving devices (battery, capacitor, genecon)

Unit 3: The Resistance Model

1. Identify bulb filaments as parts of circuits that resist charge flow.
2. Use bulb brightness and compass deflection as indicators of flow rate.
3. Distinguish flow rate (amount/sec through) from speed (distance/sec traveled).
4. Use representations tools to show flow rate and bulb brightness on circuit diagrams.
5. Explain how adding series/parallel bulbs will raise/lower “overall” resistance.
6. Describe evidence that connecting wires have much less resistance than bulbs.

Unit 4: The Compressible Fluid Model

1. Cite evidence that the mobile charge in a capacitor plate can be compressed.
2. Explain high/low “electric pressure” in terms of the compression/depletion of charge.
3. Cite evidence that a battery creates HIGH and LOW pressure in its terminals.
4. Explain why electric pressure is uniform in any wire, and in connected wires.
5. Explain how a battery and wires create a pressure difference that lights a bulb.
6. Analyze simple circuits by color-coding conducting parts to represent electric pressure.

Unit 5: What Determines Pressure in a Wire?

1. Compare the pressure difference across a long bulb and a round bulb in series.
2. Explain how steady-state pressure values arise in wires that are not connected to a battery.
3. Explain why the steady-state flow rate is the same through all resistors in a series circuit.
4. Describe the transient process by which the steady-state conditions in circuits arise from the initial conditions.
5. Compare the flow rate through a round bulb and a long bulb in parallel.
6. Analyze more complex circuits which contain a combination of series and parallel bulbs.
7. Describe the effect of a battery’s internal resistance on a circuit.
8. Explain what happens when a wire is placed in parallel with a bulb.

Unit 6: Measuring & Quantifying Circuit Variables

1. Demonstrate that an instrument labeled “voltmeter” measures electric pressure differences.
2. Identify voltmeters as having very high resistance.
3. Explain why voltmeters must be connected in parallel to properly measure pressure difference.
4. Demonstrate that an instrument labeled “ammeter” measures flow rates of moving charge.
5. Identify ammeters as having very low resistance.
6. Explain why ammeters must be connected in series to properly measure flow rate.
7. Explain how to determine the resistance of an Ohmic resistor.
8. Explain how to determine whether a resistor obeys Ohm’s Law.

Unit 7: Motors

1. Recognize that a magnetic effect exists around a current-carrying conductor.
2. The strength of the effect increases with current and decreases with distance.
3. Define magnetic vector.
4. Define a magnetic field as a pattern of magnetic vectors.
5. Describe the motor effect: the force on a current bearing wire in a magnetic field.
6. Use the Right Hand Rule for Motors to predict the direction of the magnetic force
   1. on charge moving through a magnetic field.
   2. a current bearing wire in a magnetic field.
7. Describe the function of the components necessary to construct a working motor.

Sample Materials Coming Soon

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