Science lesson plan · 9th grade (Year 10 in England) · 30 minutes
Mains electricity, AC/DC and plug safety
Electricity and magnetism
CCSS NGSS.HS-PS3-3England: GCSE Combined Science: Electricity (domestic uses and safety)
Objective and success criteria
Students will: Mains electricity, AC/DC and plug safety.
- 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: Current, voltage and resistance (V = IR)
Leads to: the next skill in this area.
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 · 4 min
- Quick retrieval from earlier learning (Current, voltage and resistance (V = IR)). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- A current of 3 A flows through a 2 Ω resistor. What is the potential difference (voltage) across it, in V? → 6 VPrompt: V = I × R
- A 24 V supply is connected across a 8 Ω resistor. What current flows, in A? → 3 APrompt: Rearrange V = I R to find I.
- A 1.25 V battery drives a current of 0.25 A through a lamp. What is the resistance of the lamp, in Ω? → 5 ΩPrompt: R = V ÷ I
Hook · 3 min
- Show a circuit with a gap and ask why the bulb doesn't light.
- Share the objective: Mains electricity, AC/DC and plug safety. Read the success criteria together.
I do: model it · 7 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: In a UK three-pin plug, which wire is this: completes the circuit at about 0 V?
- Step 1: The neutral wire (blue) completes the circuit and is at about 0 V.
- Step 2: So the answer is: neutral wire
- Answer: neutral wire
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 6 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- In a UK three-pin plug, which wire is this: stops a metal case becoming live? (live wire / neutral wire / earth wire) → earth wirePrompt: Brown, blue, green-and-yellow.
- What is the difference between ac and dc? (ac comes from batteries / ac keeps reversing direction; dc flows in one direction only / dc is used in mains sockets / there is no difference) → ac keeps reversing direction; dc flows in one direction onlyPrompt: Think about a battery compared with a wall socket.
You do: independent practice · 7 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 6 questions are on the student sheet below, with answers in the key.
Exit ticket · 3 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- Mains electricity: which statement is NOT true? (The earth wire only carries current when there is a fault. / The neutral wire is at 230 V. / The fuse is connected in the live wire. / Mains electricity in the UK is alternating current.) → The neutral wire is at 230 V.Prompt: What voltage is the neutral wire at?
- In a UK three-pin plug, which wire is this: green and yellow stripes? (live wire / neutral wire / earth wire) → earth wirePrompt: Brown, blue, green-and-yellow.
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: Current, voltage and resistance (V = IR).
- 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
- 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-9.
Free lesson plan from eurekami.com/lesson-plan-builder