Unit 11: Electricity & Magnetism

Learning Objectives:

PSc.3.3.1

• Identify interactions between charged objects - opposite charges attract and like charges repel.
• Compare the three methods of charging objects: conduction, friction, and induction – explain the re-distribution or transfer of electrons for each method for both positively and negatively charged objects.
• Compare static and current electricity related to conservation of charge and movement of charge (without calculations).

PSc.3.3.2

• Interpret simple circuit diagrams using symbols.
• Explain open and closed circuits.
• Apply Ohm’s law and the power equation to simple DC circuits: V = IR and P = VI .
• Compare series and parallel circuits. Conceptually explore the flow of electricity in series and parallel circuits. (Calculations may be used to develop conceptual understanding or as enrichment.)
• Explain how the flow of electricity through series and parallel circuits is affected by voltage and resistance.

PSc.3.3.3

• Explain how the wire in a circuit can affect the current present – for a set voltage, the current in a wire is inversely proportional to its resistance (more current exists where resistance is low); the resistance of a material is an intensive property called resistivity; increasing the length of a wire increases the resistance; increasing the temperature increases the resistance; increasing the diameter of a wire decreases its resistance.
• Explain using a cause-and-effect model how changes in composition, length, temperature, and diameter of a wire would affect the current in a circuit.

PSc.3.3.4

• Describe the characteristics and behaviors of magnetic domains.
• Explain the attractions of unlike poles and the repulsion of like poles in terms of magnetic fields.
• Explain magnetic fields produced around a current-carrying wire and wire coil (solenoid).
• Explain the relationship between strength of an electromagnet and the variance of number of coils, voltage, and core material.

PSc.3.3.5

• Explain the relationship between electricity and magnetism in practical applications such as generators and motors – the process of electromagnetic induction in electric generators that converts mechanical energy to electrical energy; transformation of electric energy to mechanical energy in motors.
• Extrapolate other practical applications such as security cards (ATM, credit or access cards), speakers, automatic sprinklers, traffic signal triggers, seismometers, battery chargers, transformers, AC-DC adapters