Lesson Plan

• Describe the relationship between power, current, voltage, and resistance.
• Derive and use the three forms of the power equation (P = I V, P = I²R, P = V²/R).
• Apply the power formulas to calculate power, current, or voltage in simple circuits.
• Explain how resistance depends on material, length, cross‑sectional area, and temperature.
• Identify and correct common misconceptions about power calculations.

• Projector or interactive whiteboard
• Worksheet with practice problems and the power formula table
• Scientific calculators
• Resistors, battery pack, ammeter and voltmeter for a demo circuit
• Handout summarising P = I V, P = I²R, P = V²/R
• Ruler (to discuss length effect on resistance)

Begin with a quick question: “If you double the voltage across a heater, what happens to its power output?” Use this to activate prior knowledge of Ohm’s law and resistance. Explain that today’s success criteria are to derive the different power forms and correctly apply them in calculations.

1. Do‑now (5'): Quick quiz on Ohm’s law and the definition of resistance.
2. Mini‑lecture (10'): Review resistance factors, introduce P = I V and derive P = I²R and P = V²/R.
3. Guided example (10'): Solve the heater problem step‑by‑step, emphasizing substitution.
4. Hands‑on activity (15'): In groups, measure I and V in a simple circuit and calculate power using each formula.
5. Concept check (5'): Exit ticket – write one real‑world scenario where P = I²R is the most convenient form.
6. Summary & misconceptions (5'): Recap key formulas and address the three common misconceptions listed in the notes.

Summarise how power, current, voltage, and resistance interrelate and why different forms of the power equation are useful. Collect the exit tickets to gauge understanding, and assign a homework task: calculate the power dissipated in three household appliances using the appropriate formula.