Science lesson plan · 8th grade (Year 9 in England) · 45 minutes
Series and parallel circuits
Electricity and magnetism
CCSS NGSS.HS-PS3-1England: KS3 Physics: Electricity and electromagnetism (current electricity)England: KS4 Combined Science: Electricity
Objective and success criteria
Students will: Series and parallel circuits.
- 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: Current and voltage rules in series and parallel circuits
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 · 5 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 1 A flows through a 6 Ω resistor. What is the potential difference (voltage) across it, in V? → 6 VPrompt: V = I × R
- A 12 V supply is connected across a 8 Ω resistor. What current flows, in A? → 1.5 APrompt: Rearrange V = I R to find I.
- A 20 V battery drives a current of 4 A through a lamp. What is the resistance of the lamp, in Ω? → 5 ΩPrompt: R = V ÷ I
Hook · 5 min
- Show a circuit with a gap and ask why the bulb doesn't light.
- Share the objective: Series and parallel circuits. Read the success criteria together.
I do: model it · 10 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: Two resistors of 8 Ω and 14 Ω are connected in series. What is their total resistance, in Ω?
- Step 1: 8 + 14 = 22
- Step 2: So the answer is: 22 Ω
- Answer: 22 Ω
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 10 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- Two lamps are in series with a 9 V battery. The voltage across one lamp is 5 V. What is the voltage across the other lamp, in V? → 4 VPrompt: In series, the battery voltage is shared between the components.
- Adding more bulbs in parallel to a battery (each in its own branch) makes each bulb… (stay about as bright as before / get much dimmer / explode / go out) → stay about as bright as beforePrompt: Each branch gets the full battery voltage.
You do: independent practice · 10 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 · 5 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- Series and parallel: which statement is NOT true? (In series, total resistance is the sum of the resistances. / Voltmeters are connected in parallel. / Ammeters are connected in parallel. / In a parallel circuit, the voltage across each branch is the same.) → Ammeters are connected in parallel.Prompt: Is current used up in a circuit?
- How is an ammeter connected to measure the current through a lamp? (across the battery only / in parallel with the lamp / it is not connected / in series with the lamp) → in series with the lampPrompt: The current must pass through the meter.
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
- Move on to: Current and voltage rules in series and parallel circuits.
- 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-8.
Free lesson plan from eurekami.com/lesson-plan-builder