p6 series and parallel circuits
4 detailed 50-minute lessons with teaching scripts, worked examples, parent guides, and assessment criteria.
Lesson Overview
Total Lessons: 4
Tier: Foundation and Higher
Duration: 50 minutes per lesson (200 minutes total)
Exam Boards: AQA, Edexcel, OCR, Eduqas, CCEA
Tier: Foundation and Higher
Duration: 50 minutes per lesson (200 minutes total)
Exam Boards: AQA, Edexcel, OCR, Eduqas, CCEA
Learning Objectives
- Explain the key ideas of p6 series and parallel circuits
- Apply p6 series and parallel circuits to exam-style questions
- Develop independent study skills
- Build cross-topic connections
Prerequisites
- Read the revision notes for p6 series and parallel circuits first (GCSE Revise summary)
- Key vocab to pre-teach: Series circuit, Parallel circuit, Adding resistors in parallel
- Basic skills: reading the summary notes and answering the practice questions there
Materials & Equipment
- Exercise book, coloured pens
- Scientific calculator
- Ruler
- Printed revision notes (link below)
- Internet for videos (see Resources)
Lesson 1: Introduction: p6 series and parallel circuits
Duration: 50 minutes
Starter Activity (5 minutes)
Quick Recall
Write down everything you already know about p6 series and parallel circuits. Then check against the key terms: Series circuit, Parallel circuit, Adding resistors in parallel. Use a mini-whiteboard or paper.
Main Content (35 minutes)
Parent/Teacher Guide:
Before lesson: Read the script below. Pre-teach key vocab: Series circuit, Parallel circuit, Adding resistors in parallel.
If stuck: Re-read the revision notes (link above), then break the content into smaller steps.
Extension: See the Stretch & Challenge ideas in Lesson 4.
Before lesson: Read the script below. Pre-teach key vocab: Series circuit, Parallel circuit, Adding resistors in parallel.
If stuck: Re-read the revision notes (link above), then break the content into smaller steps.
Extension: See the Stretch & Challenge ideas in Lesson 4.
Teaching Script (35 mins):
Mins 0-5 - Hook: "Today: p6 series and parallel circuits. By the end you will be able to answer exam questions on it unaided. It connects to the rest of Combined Science (Trilogy) because the ideas here recur across the spec."
Mins 5-20 - Direct Instruction: Work through the core ideas below one at a time; after each, ask your student to explain it back in their own words.
Mins 20-30 - Guided Practice: Model the worked example together, then let your student attempt the first practice question with guidance.
Mins 30-35 - Independent Practice: 2-3 practice questions from Lesson 3 below, with immediate feedback.
Mins 0-5 - Hook: "Today: p6 series and parallel circuits. By the end you will be able to answer exam questions on it unaided. It connects to the rest of Combined Science (Trilogy) because the ideas here recur across the spec."
Mins 5-20 - Direct Instruction: Work through the core ideas below one at a time; after each, ask your student to explain it back in their own words.
Mins 20-30 - Guided Practice: Model the worked example together, then let your student attempt the first practice question with guidance.
Mins 30-35 - Independent Practice: 2-3 practice questions from Lesson 3 below, with immediate feedback.
First Look
Start with the revision notes summary, then attempt: Foundation State the rules for current and voltage in a series circuit.
Plenary (5 minutes)
Check Out
Your student states one thing they learned and one question they still have about p6 series and parallel circuits.
Lesson 2: Core Concepts: p6 series and parallel circuits
Duration: 50 minutes
Starter Activity (5 minutes)
Review Previous Lesson
Quick recap: write 3 key points from Lesson 1 on p6 series and parallel circuits. Check them against the notes below.
Main Content (35 minutes)
Series circuit: A circuit where components are connected one after the other in a single loop. There is only one path for the current to flow.
Parallel circuit: A circuit where components are connected in separate branches. Each branch provides a different path for the current.
Adding resistors in parallel: When you add a resistor in parallel, you provide an extra path for current. This means the total resistance decreases because more current can flow overall.
Adding resistors in series: When you add a resistor in series, you make it harder for current to flow through the single loop. The total resistance increases .
Domestic circuits are wired in parallel: because: (1) each appliance gets the full mains voltage (230 V); (2) each appliance can be switched on or off independently; (3) if one appliance breaks, the others still work.
Parallel resistance: The total resistance of a parallel circuit is always less than the smallest individual resistance. For two resistors in parallel: 1/R_total = 1/R_1 + 1/R_2.
| Term | Meaning | Example |
|---|---|---|
| Current | Same everywhere: I_total = I_1 = I_2 = I_3 | Shared between branches: I_total = I_1 + I_2 + I_3 |
| Potential difference | Shared across components: V_total = V_1 + V_2 + V_3 | Same across each branch: V_total = V_1 = V_2 = V_3 |
| Resistance | Total resistance = sum of individual resistances: R_total = R_1 + R_2 | Adding resistors in parallel reduces total resistance |
| Series | 0.6 | 6.0 |
| Parallel | 2.4 | 12.0 |
Practice (10 minutes)
Q: Foundation State the rules for current and voltage in a series circuit.
Answer: In a series circuit: current is the same through all components (I_total = I_1 = I_2), and the total voltage is shared across the components (V_total = V_1 + V_2).
Plenary (5 minutes)
Explain Back
Your student teaches the key points back to you without looking. Fill any gaps immediately.
Lesson 3: Application: p6 series and parallel circuits
Duration: 50 minutes
Starter Activity (5 minutes)
Quick Recall
Recall the key terms: Series circuit, Parallel circuit, Adding resistors in parallel. Define each in one sentence.
Main Content (35 minutes)
Parent/Teacher Guide: Let your student attempt each question alone first, then compare with the model answer. Award method marks for correct working even if the final answer is wrong.
Q1: Foundation State the rules for current and voltage in a series circuit.
Answer: In a series circuit: current is the same through all components (I_total = I_1 = I_2), and the total voltage is shared across the components (V_total = V_1 + V_2).
Q2: Foundation Two 6 Ω resistors are connected in series to a 12 V battery. Calculate the total resistance and the current in the circuit.
Answer: R_total = 6 + 6 = 12 Ω. I = V / R = 12 / 12 = 1 A.
Q3: Foundation Explain why domestic circuits use parallel rather than series wiring. Give two reasons.
Answer: 1) Each appliance receives the full mains voltage (230 V). 2) Each appliance can be switched on or off independently without affecting the others. If one breaks, the rest still work.
Q4: Higher A 10 Ω and a 15 Ω resistor are connected in parallel to a 6 V supply. Calculate the current through each branch and the total current from the supply.
Answer: I through 10 Ω = 6 / 10 = 0.6 A. I through 15 Ω = 6 / 15 = 0.4 A. I_total = 0.6 + 0.4 = 1.0 A.
Q5: Higher A circuit has a 12 Ω resistor and a 4 Ω resistor in series. The supply voltage is 24 V. Calculate: (a) the total resistance, (b) the current, (c) the voltage across each resistor.
Answer: (a) R_total = 12 + 4 = 16 Ω. (b) I = 24 / 16 = 1.5 A. (c) V across 12 Ω = 1.5 x 12 = 18 V. V across 4 Ω = 1.5 x 4 = 6 V. Check: 18 + 6 = 24 V.
Q6: Higher Explain why adding a resistor in parallel decreases the total resistance of the circuit.
Answer: Adding a resistor in parallel provides an additional path for current to flow. Even though the new path has its own resistance, the total current from the supply increases because current can now flow through both paths. Since I_total increases for the same voltage, R_total = V / I_total must decrease.
Plenary (5 minutes)
Error Review
Review any questions answered incorrectly. Identify whether the error was knowledge, method, or reading the question.
Lesson 4: Exam Practice: p6 series and parallel circuits
Duration: 50 minutes
Starter Activity (5 minutes)
Command Words
Review what these command words require: state (one point), describe (say what happens), explain (say why), compare (both sides), evaluate (judgement).
Main Content (35 minutes)
Extended Answer
Extended question: Extended Answer 6 marks: Explain why domestic circuits are wired in parallel rather than in series. Refer to current, voltage and what happens if one appliance fails. <div class="
In a parallel circuit, each appliance is connected in its own separate branch across the supply. This means each appliance receives the full mains voltage of 230 V, so they all operate at their correct power rating. Each appliance can be switched on or off independently without affecting the others. If one appliance breaks or a lamp blows, the circuit in that branch is broken but current still flows through the other branches, so the other appliances continue to work. In a series circuit, if one component fails the entire circuit is broken and nothing works. Also in series, the voltage is shared between components, so appliances would not receive the correct voltage and would not work properly. The current in series is the same through all components, meaning all appliances would have to be on at the same time. Mark scheme: 1 mark — each appliance gets full 230 V, 1 mark — can be switched independently, 1 mark — if one fails others still work, 1 mark — series would share voltage, 1 mark — series: one failure stops all, 1 mark — series: all must be on together
Exam Tips: Remember the key difference: series = one loop, current same, voltage shared ; parallel = multiple branches, current shared, voltage same . | In series, adding a resistor increases total resistance. In parallel, adding a resistor decreases total resistance. | When a question asks about domestic circuits, always mention parallel because each appliance gets full voltage and works independently. | For series calculations: find total R first, then find I, then find V across each component. | For parallel calculations: each branch gets full voltage, so calculate I through each branch separately, then add currents for the total. | The total resistance in parallel is always less than the smallest i
Common Errors: Watch Out! 1. Wrong: Current is "used up" by components in a series circuit Correct: Current is the same through all components in series — it is energy that is transferred, not the current itself 2. Wrong: Parallel circuits have the same current everywhere Correct: Only the voltage is the same across each branch; the current splits at junctions — I_total = I₁ + I₂ + I₃ 3. Wrong: Adding resistors in parallel increases the total resistance Correct: Adding resistors in parallel provides extra paths for current, so total resistance decreases — it is always less than the smallest individual resistance
AO3 - Reasoning & Interpretation: Analysis and Evaluation A student sets up a circuit with two 10 Ω resistors and a 12 V battery. They measure the following: Arrangement Total current (A) V across R₁ (V) V across R₂ (V) Series 0.6 6.0 6.0 Parallel 2.4 12.0 12.0 (a) Show that the series current measurement is consistent with R_total = R₁ + R₂. (b) One of the resistors is replaced with a faulty 10 Ω resistor that has a much higher actual resistance. In which arrangement (series or parallel) would this fault be easier to detect from current readings alone? Justify your answer. (c) The student's ammeter has a zero error of +0.05 A. Explain how this affects the calculated total resistance in both arrangements and how to correct f
Stretch & Challenge (Grade 8-9):
- Synoptic links: explain how p6 series and parallel circuits connects to another Combined Science (Trilogy) topic you have studied
- Real-world: research one real-world use or example of p6 series and parallel circuits
- Critical: "What are the limitations of the models used in p6 series and parallel circuits?"
Plenary (5 minutes)
Assessment Criteria
- Got it: Confident explanation + correct worked examples
- Getting there: Main points OK, needs support with detail
- Not yet: Confused on key concepts - re-run Lesson 2
Homework & Consolidation
- Consolidation: Re-answer any Lesson 3 practice questions answered incorrectly (20 mins)
- Retrieval: Write flashcards for the key terms: Series circuit, Parallel circuit, Adding resistors in parallel (10 mins)
- Exam practice: One past-paper question on p6 series and parallel circuits from the board websites (15 mins)
- Extension: Explain p6 series and parallel circuits to someone else in your own words (10 mins)