Primary General Studies | Simple Circuits: Series and Parallel (for tutors)

Primary General Studies | Simple Circuits: Series and Parallel (for tutors) | 1.5 V cells, 3 V and 0.2 A

2026-11-04

Tutor lesson-prep guides · Primary General Studies

Pupils can say current runs from the battery to the bulb but cannot explain why two cells give a brighter light. Two 1.5 V cells and one 15 ohm bulb settle it with three numbers.

Objectives — Pupils can: (1) draw a closed circuit with cell, wires, bulb and switch; (2) tell series from parallel (series shares one current path, parallel shares one voltage); (3) compute 1.5 V times 2 equals 3 V and 3 divided by 15 equals 0.2 A, and state one mains safety rule.

01 Prerequisites (3-minute check)

If any of these fails, fix it before the lesson starts.

Skill	Quick check	Pass mark
Source of current	What are the two ends of a cell called?	Positive and negative terminals
Circuit parts	What does a lit bulb need?	Cell, wires, bulb and a closed loop
Division	What is 3 divided by 15?	0.2

02 Lesson flow (60 minutes)

Time	Stage	Tutor does	Student does
0-8 min	Hook	One bulb, two cells; why two	One sentence each
8-20 min	Closed loop	Cell, wires, bulb, switch; find the gap	Draw it once
20-32 min	Series	Two 1.5 V cells in series give 3.0 V	Draw and measure
32-44 min	Parallel	Two bulbs in parallel each get 3.0 V	Compare brightness
44-56 min	Sums and safety	3.0 divided by 15 is 0.2 A; 5 hours use 3.0 Wh	Compute twice
56-60 min	Exit check	Three questions collected and marked	Work alone

03 Teaching script (read it out)

Scene 1: Closed loop before parts

Pupils leave gaps or omit the switch, so the bulb cannot light. Start by drawing one complete ring, then label each part on it.
The line to use: current needs a path from the positive terminal, through the bulb, back to the negative terminal; break the ring anywhere and nothing flows.

Pupils do: circle which of three diagrams will light and mark where the break is.

Scene 2: Count the paths to tell series from parallel

Series has one path, so the current is the same everywhere and voltages add: two 1.5 V cells give 3.0 V. Parallel has several paths, so voltages match and currents add.
One worked sum makes it concrete: 3.0 V across a 15 ohm bulb gives 3.0 divided by 15, which is 0.2 A, and 3.0 times 0.2 is 0.6 W. Two such bulbs in series instead have 30 ohms in total, so the current drops to 0.1 A and each bulb is dimmer.

Pupils say: is the dimmer bulb caused by less current or less voltage (less current; each bulb gets only 1.5 V).

Scene 3: Safety as one doable rule

Bring the numbers into daily life: a 0.6 W bulb for 5 hours uses 3.0 Wh, that is 0.003 kWh. Small, but sockets overload when several appliances share one outlet.
Keep exactly one rule: never plug two high-power appliances into the same socket, and never touch a switch with wet hands. Short rules are the ones pupils keep.

Pupils do: name two high-power appliances at home and say which pair must not share a socket.

04 Question types and worked steps

Type	Example	Steps	Answer
Spot the circuit	Which of three diagrams lights	Find the closed loop, find the gap	Open circuit is not a short circuit
Series or parallel	Classify two diagrams	Ask how many paths the current has	One path means series
Calculation	3.0 V over 15 ohms	I equals V divided by R, with units	Answer 0.2 A
Safety	Judge three situations	Give a reason plus an action	Be specific, not careful

Sanity check (teach this): Check the arithmetic: two 1.5 V cells in series give 3.0 V rather than 1.5 V; 3.0 V across 15 ohms gives 0.2 A; two bulbs in series total 30 ohms, so the current is 0.1 A with 1.5 V across each; 0.6 W for 5 hours is 3.0 Wh or 0.003 kWh.

05 Independent practice (3 questions)

Question	Answer	What to watch
Draw a loop	Cell, switch, bulb	The ring must close
Sort four diagrams	Series or parallel	Use the number of paths
Current sum	3.0 V and 15 ohms	Answer 0.2 A with units
Safety sentences	Three situations	Each needs a reason and an action

06 Common mistakes and what to say

Mistake	Student writes	Say this
Loop left open	Only one wire to the bulb	Current must return to the negative terminal, otherwise the loop is not closed.
Series called parallel	Both cells are the same	Series adds voltage, parallel keeps it; check whether the cells are end to end or side by side.
Units dropped	The answer is 0.2	0.2 of what? Current is in amperes, and missing units lose marks.
Vague safety answer	Do not plug things in carelessly	Say it concretely: one socket, one high-power appliance, for example a heater or a kettle.

07 Homework (paper, section and question numbers)

Simple circuit exercises — Questions 9 to 12: circuit spotting and current sums
Prep guide index — Compare similar chapters
Redo this chapter — Draw one series and one parallel circuit and compute the current in each

08 Exit check (last 5 minutes)

Question	Answer	Decision
Two 1.5 V cells in series	3.0 V	Answer 1.5 V means act two again
Voltage in parallel	The same in every path	Answer added means act two again
Current for 3.0 V over 15 ohms	0.2 A	Answer 0.5 A means repeat the sum

09 Tutor FAQ

Do pupils need Ohm law?

Only the single step of V divided by R, with no derivation.

Why does a bulb glow?

Current heats the filament until it emits light; that is far enough at primary level.

Why is a short circuit dangerous?

Resistance falls near zero, so current surges and wires overheat; in pupil language, the current rushes straight through.

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A TutorZone lesson-prep guide. Written by the TutorZone team; questions and lesson flow are original and are not taken from any school or publisher material.