Science lesson plan · 10th grade (Year 11 in England) · 60 minutes
Power and energy in circuits (P = I²R, E = QV)
Electricity and magnetism
CCSS NGSS.HS-PS3-1England: GCSE Combined Science: Electricity (energy transfers)
Objective and success criteria
Students will: Power and energy in circuits (P = I²R, E = QV).
- I can answer questions on today's skill on my own, without help.
- I can explain each step and say why it works.
- I can check my answer and spot a mistake.
Before and after
Needs first: Charge, current and time (Q = I t); Electrical power, charge and energy
Leads to: Transformers and the National Grid
Materials: Circuit kits (cells, wires, bulbs), Circuit symbol cards, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).
Warm-up · 6 min
- Quick retrieval from earlier learning (Charge, current and time (Q = I t); Electrical power, charge and energy). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- A current of 3 A flows for 20 s. How much charge flows, in coulombs (C)? → 60 CPrompt: Q = I × t
- An appliance on US mains (120 V) draws a current of 4 A. What is its power, in W? → 480 WPrompt: P = I × V
- 1800 C of charge flows through a lamp in 10 minutes. What is the current, in A? → 3 APrompt: Convert minutes to seconds first.
Hook · 6 min
- Show a circuit with a gap and ask why the bulb doesn't light.
- Share the objective: Power and energy in circuits (P = I²R, E = QV). Read the success criteria together.
I do: model it · 12 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: A current of 0.5 A flows through a 10 Ω resistor. What power is transferred, in W?
- Step 1: 0.5² × 10 = 0.25 × 10 = 2.5
- Step 2: So the answer is: 2.5 W
- Answer: 2.5 W
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 12 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- A current of 3 A flows through a 10 Ω resistor. What power is transferred, in W? → 90 WPrompt: P = I² × R
- 100 C of charge passes through a potential difference of 6 V. How much energy is transferred, in J? → 600 JPrompt: E = Q × V
You do: independent practice · 17 min
- Students work on the student sheet. Circulate and check the first two answers of every student early.
- Students who finish: write a question of their own for a partner, with the answer.
The 8 questions are on the student sheet below, with answers in the key.
Exit ticket · 7 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- 50 C of charge passes through a potential difference of 9 V. How much energy is transferred, in J? → 450 JPrompt: E = Q × V
- A current of 1 A flows through a 12 Ω resistor. What power is transferred, in W? → 12 WPrompt: P = I² × R
Watch out for
- Everyday meanings of words getting in the way of the science meaning: define key words explicitly.
- Remembering facts without the reason: ask "why?" and "what is the evidence?"
Support and stretch
Support
- Review first: Charge, current and time (Q = I t).
- Use concrete materials: circuit kits (cells, wires, bulbs).
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Move on to: Transformers and the National Grid.
- Explain a common mistake in writing and how to fix it.
- Write a word problem that uses today's skill, then solve a partner's.
Homework and more practice
Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-10.
Free lesson plan from eurekami.com/lesson-plan-builder