Physics — Catch-Up & Consolidation Lesson

Electricity Calculations & Bridge to Waves

⚡🔢🌊

Re-building L2c & L4 calculations | Bridge to Waves

Missed a lesson? You're in exactly the right place. Lots of us were away for the calculation lessons, so today we re-build them together from scratch — slowly, step by step. This isn't a test. It's a catch-up.

✓

L1 — Recall circuit symbols, series & parallel (quick recap — you didn't miss this one)

✓

L2c — Use V = I × R and rearrange it (find V, I or R)

✓

L4 — Explain electron flow & solve series circuit calculations

🏆 Today's Success Criteria

Foundation: I can use V = I × R and add resistances in series.

Middle: I can rearrange V = IR and find the current in a series circuit.

Higher: I can solve a full series problem and explain voltage sharing.

🖨️ Pupil Packs

⏱️ 40-Minute Pacing (calc-focused)

Core: Arrival → Starter → I Do VIR → We Do Carousel → I Do Series → We Do Series Solver → Independent → Exit

🟠 FLEX (use if time/confidence allows): Common Mistakes + Symbol Speed Match. You didn't miss L1 symbols, so they're optional today.

⏱️ 4 min

Arrival Task

Arrival – How Much Do You Remember?

No notes. Answer from memory. One from L1, one from L2c, one from L4. If you were away — just have a go. We re-build it all together shortly.

1. 🟢 (L1)

Draw the circuit symbol for a cell and a lamp.

Cell: long line + short line. Lamp: circle with a cross.

2. 🟢 (L2c)

Write the formula linking voltage, current and resistance.

V = I × R

3. 🟢 (L4)

What particles carry current in a metal wire?

Electrons (negatively charged).

4. Bridge 🌊

Name two types of wave you know about.

Any from: water waves, sound waves, light waves, radio waves, etc.

1. 🟠 (L1)

State how an ammeter and voltmeter must be connected.

Ammeter: in series. Voltmeter: in parallel.

2. 🟠 (L2c)

A 12 V battery is connected to a 6 Ω resistor. Calculate the current.

I = V ÷ R = 12 ÷ 6 = 2 A

3. 🟠 (L4)

In which direction do electrons flow — + to − or − to +?

− to + (opposite to conventional current).

4. Bridge 🌊

Drop a stone into a pond. Does the water travel outward, or just the energy?

Ripples spread outward. The energy travels, but the water itself stays roughly in place (bobs up and down).

1. 🔵 (L1)

Explain why houses are wired in parallel, not series.

Each appliance gets full voltage (230 V). If one breaks, the others keep working.

2. 🔵 (L2c)

A hairdryer uses 230 V and draws 10 A. Calculate its resistance.

R = V ÷ I = 230 ÷ 10 = 23 Ω

3. 🔵 (L4)

A 15 V battery connects to 5 Ω and 10 Ω in series. Find the current and V across the 10 Ω.

R = 15 Ω. I = 15 ÷ 15 = 1 A. V = 1 × 10 = 10 V.

4. Bridge 🌊

Both electricity and waves transfer energy. In a wave, how is energy transferred without anything physically travelling?

Particles vibrate and pass the energy to their neighbours — the energy moves forward, but the particles stay roughly in place.

⏱️ 3 min

Starter

Starter: Electricity Brain Dump 🧠

Instructions: In 3 minutes, write down everything you can remember about electricity. Facts, formulas, units, rules — anything! Blank under a topic? That's fine — it just shows what we'll re-build today.

📝 Brain Dump — Write everything!

Challenge yourself: can you get 10+ facts?

🟢 5+ facts = Good | 🟠 10+ facts = Great | 🔵 15+ facts = Expert!

💡 Topics to jog your memory:

L1: Circuit symbols, series vs parallel, ammeter/voltmeter

L2c: V = I × R, units, water analogy, VIR triangle

L4: Electron flow, conventional current, series R rules, voltage sharing

💡 Did You Know?

Revisiting content 24 hours later can boost long-term memory by up to 80%. Catching up today fires the pathways back up — even if you missed the lesson first time.

🌟 After 3 minutes: Swap books with a partner. Read their list. Add anything they missed in a different colour. Discuss!

⏱️ 4 min

I Do

I Do: The VIR Triangle — From Scratch (L2c)

Missed the Ohm's Law lesson? Watch this carefully. Every calculation uses the same 3 steps. I'll reveal them one at a time.

V = I × R

👆 Tap a button — I'll cover that letter and show the formula.

Bigger pump (more V) → faster flow (more I). Narrower pipe (more R) → slower flow (less I). That's V = I × R!

Every calculation, every time: ① write the Formula → ② Substitute the numbers → ③ Answer + Unit (V, A or Ω). Even the formula alone can earn a mark.

↗ Open on YouTube

① Find R — cover R

Step 1 – Formula: R = V ÷ I

Step 2 – Substitute: R = 10 ÷ 2

Step 3 – Answer: R = 5 Ω ✅

② Find I — cover I

Step 1: I = V ÷ R

Step 2: I = 12 ÷ 4

Step 3: I = 3 A ✅

③ Find V — cover V

Step 1: V = I × R

Step 2: V = 0.5 × 12

Step 3: V = 6 V ✅

⚠️ The #1 mistake: "I = V × R"
Truth: To find I or R you DIVIDE. You only multiply when you want V. The triangle never lies — cover the unknown.

⏱️ 5 min

We Do

We Do: VIR Problem Carousel 🎠 (L2c)

Your turn. The first one is done for you — copy the routine. Calculate the missing value, type it, check!

✅ Worked example — Lamp

V = 6 V, R = 3 Ω, find I. → Cover I → I = V ÷ R = 6 ÷ 3 = 2 A ✅

👥 Think-Pair-Share: try it → discuss with your partner → agree the answer.

🔦

Torch

V = 3 V, R = 6 Ω

I = ?

Cover I → I = V ÷ R. Put in 3 ÷ 6.

📱

Phone Charger

I = 2 A, R = 2.5 Ω

V = ?

Cover V → V = I × R. Put in 2 × 2.5.

💡

LED Bulb

V = 12 V, I = 0.5 A

R = ?

Cover R → R = V ÷ I. Dividing by 0.5 doubles the number.

🧹

Vacuum

V = 230 V, R = 23 Ω

I = ?

Cover I → I = V ÷ R = 230 ÷ 23.

🎮

Game Controller

I = 0.1 A, R = 30 Ω

V = ?

Cover V → V = I × R = 0.1 × 30.

🔌

Kettle

V = 230 V, I = 10 A

R = ?

Cover R → R = V ÷ I = 230 ÷ 10.

Solved:

0/6

⏱️ 4 min

I Do

I Do: Series Circuit Calculations — From Scratch (L4)

Missed the series lesson? Watch the 4-step method. In series: add the resistances, the current is the same everywhere, and the voltages add up to the supply.

✏️ Problem

An 18 V battery is connected to a 6 Ω and a 12 Ω resistor in series. Find R_total, the current, and the voltage across each.

Step 1 — Add the resistances:
R_total = R₁ + R₂ = 6 + 12 = 18 Ω

Step 2 — Find the current:
I = V ÷ R_total = 18 ÷ 18 = 1 A

Step 3 — Voltage across each:
V₁ = I × R₁ = 1 × 6 = 6 V
V₂ = I × R₂ = 1 × 12 = 12 V

Step 4 — Check: V₁ + V₂ = 6 + 12 = 18 V = supply ✅

Series Circuit — watch the charge flow

The dots keep the same spacing & speed all the way round — the current is the same everywhere.

Supply:18 V

V₁ 6 V

V₂ 12 V

Current now: 1 A — and the 12 Ω always grabs double the voltage of the 6 Ω (voltage shares by resistance).

R_total = R₁ + R₂

The routine, every series question: ① Add R → ② I = V ÷ R_total → ③ V = I × R for each → ④ Check the voltages add up.

↗ Open on YouTube

⚠️ Two classic slips: "R total = 6 × 12" — no, you ADD in series. And "current shrinks after a resistor" — no, current is the SAME everywhere; it's the voltage that's shared.

🌟 Notice: the 12 Ω gets double the voltage of the 6 Ω — voltage is shared in proportion to resistance.

⏱️ 5 min

We Do

We Do: Series Circuit Step Solver 🧮 (L4)

Your turn — one step at a time. A 20 V battery connects to 5 Ω and 15 Ω in series. Use a hint whenever you're stuck — that's what they're for.

👥 Think-Pair-Share: try each step → check with your partner → agree.

Step 1: Add the resistances (R_total)

R_total = 5 + 15 = Ω

Series resistances ADD together: 5 + 15.

Step 2: Find the current (I)

I = V ÷ R_total = 20 ÷ 20 = A

Divide the battery voltage by R_total: 20 ÷ 20.

Step 3: Voltage across the 5 Ω

V₁ = I × R₁ = 1 × 5 = V

Multiply the current by this resistor: 1 × 5.

Step 4: Voltage across the 15 Ω

V₂ = I × R₂ = 1 × 15 = V

Multiply the current by this resistor: 1 × 15.

Step 5: CHECK — do they add up?

V₁ + V₂ = 5 + 15 = V = supply?

Add your two voltages — they should equal the 20 V supply.

Steps correct: 0 / 5

🌟 Finished? Try it again with a 24 V battery, 4 Ω + 8 Ω. (R=12, I=2 A, V₁=8 V, V₂=16 V.)

⏱️ 3 min · FLEX

I Do · FLEX

Top 4 Mistakes to Avoid

Optional recap. Everyone makes these — spotting them is how you stop losing easy marks.

❌ Mistake 1: Multiplying to find I

"I = V × R = 12 × 4 = 48"

✅ Fix: I = V ÷ R = 12 ÷ 4 = 3 A

❌ Mistake 2: Multiplying series R

"R total = 3 × 6 = 18 Ω"

✅ Fix: R total = 3 + 6 = 9 Ω (ADD in series)

❌ Mistake 3: Forgetting the unit

"V = 3 × 4 = 12" (no unit!)

✅ Fix: V = 3 × 4 = 12 V (always write V, A or Ω)

❌ Mistake 4: Current changes in series

"The current is smaller after the resistor"

✅ Fix: In series, current is the SAME everywhere. Voltage is what's shared.

💡 Rule of thumb: finding I or R → you DIVIDE. Finding V → you MULTIPLY. The triangle never lies!

⏱️ 5 min · FLEX

We Do · FLEX

Symbol Speed Match ⚡ (L1)

Optional L1 revision. Click a component, then click its matching description. Match all 6!

Component (click first)

Cell

Ammeter

Voltmeter

Resistor

Switch (open)

Lamp

How it's connected / what it does

Measures voltage. Connected in parallel.

Converts electrical energy to light + heat.

Provides voltage (push). Long + short line.

Breaks the circuit. Gap in the wire.

Measures current. Connected in series.

Opposes flow of current. Rectangle symbol.

Matched: 0 / 6

⏱️ 6 min

Independent Work

Complete your printed pack. The calculations you've just re-built are the focus. Use your scaffolding sheet whenever you need it.

📝 Pack Contains:

A: Multiple Choice — mixed L1/L2c/L4 (4 Qs)

B: Short Answer — symbols, definitions, V=IR

C: Long Answer — scaffolded series calculation

D: Exam-Style — full series circuit problem

Need help? The Scaffolding Sheet has every formula, the series rules, and the VIR triangle.

📝 Exam Command Words:
State = write a fact, no explanation.
Calculate = formula → substitute → answer + unit.
Explain = what happens AND why (use "because").
Describe = what happens, step by step.

🏆 Success Criteria

Foundation (U–1): I can use V = I × R and add resistances in series.

Middle (1–2): I can rearrange V = IR and find the current in a series circuit.

Higher (3–5): I can solve a full series problem, find a missing R, and explain voltage sharing.

✅ Tick as you go — Success checklist

I can use V = I × R and rearrange it

I can add resistances in series (R total)

I can find the current in a series circuit

I can explain what carries current in metals

⏱️ 3 min

Exit Ticket

Exit Ticket — L1, L2c & L4 Cumulative

6 questions — 2 from each lesson. No notes.

🟢 I'm confident — I could teach this

🟡 Getting there — need more practice

🔴 I'm stuck — I need help

1. Name the quantity measured with an ammeter.

Current (in amps).

2. In series, is the current the same or different everywhere?

The same everywhere.

L2c

3. I = 3 A, R = 4 Ω. Calculate V.

V = 3 × 4 = 12 V

L2c

4. What unit is resistance measured in?

Ohms (Ω)

5. What carries current in a metal wire?

Negatively charged electrons.

6. 4 Ω + 6 Ω in series. R total = ?

R = 4 + 6 = 10 Ω

🌊 Coming next lesson: a brand-new topic — WAVES! Amplitude, wavelength, frequency, and how waves transfer energy without transferring matter. Get excited!

Knowledge Organiser: Electricity Calculations (L1 · L2c · L4)

Name: ____________________ Class: __________ Date:

How to use: Read this before you start. Refer back during independent work. Cover it for the exit ticket — that tests what you actually remember!

Topic	Key Facts
Circuit symbols (L1)	Cell, battery, switch, lamp, resistor, variable resistor, ammeter, voltmeter.
Series	One loop. Current same everywhere. Voltages add up. R total = R₁ + R₂.
Parallel	Branches. Voltage same across each. Currents add up.
Ammeter / Voltmeter	Ammeter measures current (A), in SERIES. Voltmeter measures voltage (V), in PARALLEL.
V = I × R (L2c)	V in volts, I in amps, R in ohms. Rearrange: I = V÷R, R = V÷I.
Current	Rate of flow of charge. 1 A = 1 coulomb per second.
Electron flow (L4)	Current in metals = flow of negatively charged electrons. Flow: − → + (conventional + → −).
Series calc method (L4)	1. R total = R₁+R₂ → 2. I = V÷R total → 3. V = I×R for each → 4. Check voltages add up.

🧠 Memory Tricks

VIR Triangle: V on top, I × R on bottom. Cover what you want = formula!

Series: "Add R, Same I, Share V" (3 words for everything).

÷ or ×? Finding I or R → DIVIDE. Finding V → MULTIPLY.

Step method: Formula → Substitute → Calculate → Unit. Every. Single. Time.

Arrival Task – Foundation (U–1) 🟢

1 (L1). Draw the symbol for a cell and a lamp.

2 (L2c). Write V = I × R.

3 (L4). What particles carry current in metals?

4 (Bridge). Name two types of wave.

Arrival Task – Middle (1–2) 🟠

1 (L1). How are ammeter + voltmeter connected?

2 (L2c). 12 V, 6 Ω. Calculate I.

3 (L4). Electron flow direction?

4 (Bridge). Stone in pond — does water travel outward or just energy?

Arrival Task – Higher (3–5) 🔵

1 (L1). Why are houses wired in parallel?

2 (L2c). 230 V, 10 A. Calculate R.

3 (L4). 15 V, 5 Ω + 10 Ω series. Find I and V across 10 Ω.

4 (Bridge). How do waves transfer energy without matter travelling?

Starter: Brain Dump

Write down EVERYTHING you remember about electricity (L1, L2c, L4). Facts, formulas, units, rules, diagrams.

Write here...

We Do Worksheet

Part A: VIR Carousel — Calculate the missing value (L2c)

Worked example — Lamp: V = 6, R = 3, find I → I = V ÷ R = 6 ÷ 3 = 2 A.

Appliance	V	I	R
🔦 Torch	3 V	?	6 Ω
📱 Charger	?	2 A	2.5 Ω
💡 LED	12 V	0.5 A	?
🧹 Vacuum	230 V	?	23 Ω
🎮 Controller	?	0.1 A	30 Ω
🔌 Kettle	230 V	10 A	?

Part B: Series Step Solver (L4)

20 V battery, 5 Ω + 15 Ω in series.

Step	Working	Answer
1. R total	5 + 15 =
2. Current	I = 20 ÷ ___ =
3. V across 5 Ω	V = ___ × 5 =
4. V across 15 Ω	V = ___ × 15 =
5. Check	___ + ___ =	= 20 V? ✅/❌

Scaffolding Sheet — All Electricity Formulas

VIR Triangle (L2c)

Find	Formula	Example
V	V = I × R	V = 3 × 4 = 12 V
I	I = V ÷ R	I = 12 ÷ 4 = 3 A
R	R = V ÷ I	R = 12 ÷ 3 = 4 Ω

Cover what you want — the rest is the formula!

Series Circuit Rules (L4)

R total = R₁ + R₂ | Current same everywhere | Voltages add up to supply

Method: 1. R total → 2. I = V ÷ R total → 3. V = I × R for each → 4. Check

Electron Flow (L4)

Current in metals = negatively charged electrons. Flow: − → +. Conventional: + → −.

Independent Work – Foundation (Grades U–1)

Name: ____________________ Date:

You've got this! Use your scaffolding sheet. Write the formula first every time. Show your working — even partial working earns marks.

Section A: Multiple Choice

1. An ammeter is connected in… [ ] Series [ ] Parallel

2. V = I × R. If I = 2 A, R = 5 Ω, V = … [ ] 7 V [ ] 10 V [ ] 2.5 V

3. Current in metals is a flow of… [ ] Protons [ ] Electrons [ ] Neutrons

4. In series, total R is found by… [ ] Adding [ ] Multiplying [ ] Dividing

Section B: Short Answer

5. Draw the circuit symbol for a switch and a resistor.

6. V = 9 V, I = 3 A. Calculate R. (Formula: R = V ÷ I)

7. State one difference between series and parallel.

Section C: Long Answer (Grade 2 Challenge — scaffolded)

8. (4 marks) A 10 V battery connects to 2 Ω + 3 Ω in series.

Hint: follow the steps. The formula is given each time.

(a) R_total = R₁ + R₂ = 2 + 3 = _______ Ω [1]

(b) I = V ÷ R_total = 10 ÷ _______ = _______ A [1]

(d) Check: V₁ + V₂ = _______ + _______ = _______ V = supply? ✅ / ❌ [1]

Section D: Exam-Style

9. (3 marks) State what carries current in a metal wire [1]. State their charge [1]. State the direction they flow [1].

Independent Work – Middle (Grades 1–2)

Name: ____________________ Date:

Push yourself! Show full working for every calculation. Section D is your Grade 3 stretch.

Section A: Recall

1. State V = I × R and what each letter stands for with units.

2. What is the difference between electron flow and conventional current?

3. V = 230 V, R = 46 Ω. Calculate I.

4. Why must an ammeter have very low resistance?

Section B: Application

5. Complete:

V	I	R
?	4 A	5 Ω
12 V	?	3 Ω
9 V	0.5 A	?

Section C: Long Answer

6. (5 marks) 12 V battery, 4 Ω + 8 Ω series. (a) R total [1]. (b) I [1]. (c) V across each [2]. (d) Explain why the 8 Ω gets more voltage [1].

Section D: Exam-Style (Grade 3 Stretch)

7. (4 marks) A student says "current gets used up as it passes through a resistor." (a) Explain why this is wrong [2]. (b) What does change as current passes through a resistor? [2]

Independent Work – Higher (Grades 3–5)

Name: ____________________ Date:

Aim high! Full sentences for explanations. Section D includes Grade 5 challenges.

Section A: Recall

1. Explain why metals conduct but plastics don't, in terms of electrons. [3]

2. Explain why voltage is shared in proportion to resistance in series. [2]

Section B: Application

3. Complete:

V supply	R₁	R₂	I
15 V	5 Ω	10 Ω
?	8 Ω	12 Ω	0.5 A
24 V	?	6 Ω	2 A

Section C: Long Answer

4. (5 marks) Explain, using electron flow and V = IR, what happens in a series circuit when you add a second resistor. Describe the effect on total R, current, and how voltage is shared.

Section D: Exam-Style (includes Grade 5 Challenge)

5. (6 marks) A circuit has a 6 V battery and two resistors in series. The current is 0.25 A. R₁ = 8 Ω.

(a) Calculate R total. [2]

(b) Calculate R₂. [1]

(d) State the direction of electron flow through this circuit. [1]

Exit Ticket – Foundation (U–1)

Name: _________________________ Date:

1) What does an ammeter measure?

2) In series, is current same or different?

L2c

3) I=3 A, R=4 Ω. Find V.

L2c

4) Unit of resistance?

5) What carries current in metals?

6) 4Ω + 6Ω series. R total?

Exit Ticket – Middle (1–2)

Name: _________________________ Date:

1) How is voltmeter connected?

2) Two differences: series vs parallel.

L2c

3) V=9, R=3. Find I.

L2c

4) Define current in terms of charge.

5) Electron flow vs conventional direction?

6) 12V, 4Ω+8Ω series. Find I and V across 8Ω.

Exit Ticket – Higher (3–5)

Name: _________________________ Date:

1) Why is ammeter in parallel dangerous?

2) Why parallel for houses?

L2c

3) 230V, 5A. Find R.

L2c

4) Why does ↑V cause ↑I at fixed R?

5) Metals vs plastics: why conduct?

6) 15V, I=0.5A, R₁=10Ω. Find R₂ + V each.

👁️ TA Brief — This Slide

🎯 Random Pupil Picker

Lesson Complete!

Electricity Calculations & Bridge to Waves

🏆 Today's Success Criteria

🖨️ Pupil Packs

⏱️ 40-Minute Pacing (calc-focused)

Arrival – How Much Do You Remember?

1. 🟢 (L1)

2. 🟢 (L2c)

3. 🟢 (L4)

4. Bridge 🌊

1. 🟠 (L1)

2. 🟠 (L2c)

3. 🟠 (L4)

4. Bridge 🌊

1. 🔵 (L1)

2. 🔵 (L2c)

3. 🔵 (L4)

4. Bridge 🌊

Starter: Electricity Brain Dump 🧠

📝 Brain Dump — Write everything!

💡 Topics to jog your memory:

💡 Did You Know?

I Do: The VIR Triangle — From Scratch (L2c)

① Find R — cover R

② Find I — cover I

③ Find V — cover V

We Do: VIR Problem Carousel 🎠 (L2c)

✅ Worked example — Lamp

I Do: Series Circuit Calculations — From Scratch (L4)

✏️ Problem

Series Circuit — watch the charge flow

We Do: Series Circuit Step Solver 🧮 (L4)

Top 4 Mistakes to Avoid

❌ Mistake 1: Multiplying to find I

❌ Mistake 2: Multiplying series R

❌ Mistake 3: Forgetting the unit

❌ Mistake 4: Current changes in series

Symbol Speed Match ⚡ (L1)

Independent Work

📝 Pack Contains:

🏆 Success Criteria

✅ Tick as you go — Success checklist

Exit Ticket — L1, L2c & L4 Cumulative

Knowledge Organiser: Electricity Calculations (L1 · L2c · L4)

🧠 Memory Tricks

Arrival Task – Foundation (U–1) 🟢

Arrival Task – Middle (1–2) 🟠

Arrival Task – Higher (3–5) 🔵

Starter: Brain Dump

We Do Worksheet

Part A: VIR Carousel — Calculate the missing value (L2c)

Part B: Series Step Solver (L4)

Scaffolding Sheet — All Electricity Formulas

VIR Triangle (L2c)

Series Circuit Rules (L4)

Electron Flow (L4)

Independent Work – Foundation (Grades U–1)

Section A: Multiple Choice

Section B: Short Answer

Section C: Long Answer (Grade 2 Challenge — scaffolded)

Section D: Exam-Style

Independent Work – Middle (Grades 1–2)

Section A: Recall

Section B: Application

Section C: Long Answer

Section D: Exam-Style (Grade 3 Stretch)

Independent Work – Higher (Grades 3–5)

Section A: Recall

Section B: Application

Section C: Long Answer

Section D: Exam-Style (includes Grade 5 Challenge)

Exit Ticket – Foundation (U–1)

Exit Ticket – Middle (1–2)

Exit Ticket – Higher (3–5)

We Do – Class Evidence