You will learn
- Define series circuit.
- Predict effects of adding bulbs.
- Explain shared voltage.
- State series disadvantages.
Version 0.2 · expanded edition · built from cited public sources Content is based on the official frameworks and sources listed under Sources and standards. No official endorsement is claimed. Written in the style of common primary school assessments. No exam result is promised.
Student lesson
- One loop only.
- Same current everywhere.
- More bulbs means dimmer bulbs.
- One break stops everything.
Words to know
components joined one after another in a single loop
the cell’s voltage divided between components
less bright
a break or problem in a circuit
1. Discover: The fairy lights
Old fairy lights are joined in series. When one bulb breaks, the whole string goes out. “There is only one path for current,” says Mr Adjei. “Newer sets use clever wiring so one fault does not stop the others.”
Think: Why do all bulbs in a series circuit go out together?
2. Understand: Series
Idea 1: One loop
In a series circuit the components are joined one after another in a single loop. The same current flows through all of them.
Idea 2: Voltage
The cell’s voltage is shared between the components. Add more bulbs and each gets less voltage, so each is dimmer.
Idea 3: Drawbacks
If one component breaks, the loop is open and everything stops. Series circuits are good when you want one switch to control everything, like a chain of safety switches.
3. Worked examples
Example 1 (I show you): Predict
Add bulb.
- Dimmer.
- Same current.
- Shared voltage.
Answer: Both dimmer.
Example 2 (We do it together): Explain
Break.
- One path.
- Open.
- All stop.
Answer: All go out.
Example 3 (You try): Draw
Series.
Show the steps and answer
- Cell.
- Two bulbs.
- One loop.
Answer: Diagram.
Did you know?
Many older string lights used series wiring, so one dead bulb meant a hunt through the whole string.
Why this matters
Series circuits show how current and voltage behave.
4. Explore: Series bulbs
Build a circuit with one bulb, then two and three bulbs in series from one 1.5 V cell, compare brightness and record what happens when one bulb is removed.
- Build one-bulb circuit.
- Add a bulb.
- Compare brightness.
- Remove one bulb.
Think about it: what did you notice?
What did you notice? Bulbs got dimmer and all went out when one was removed.
5. Practise
Say it in a sentence
Use these starters when you talk about the lesson. Say them out loud.
- A ___ circuit has components in one loop.
- ___ voltage is divided between components.
- A ___ bulb is less bright.
- A ___ is a break or problem.
Guided practice
Question 1. What is series?
One loop.
Question 2. Same what?
Current.
Question 3. Voltage is?
Shared.
Independent practice
Level 1: Start
- What is series?
- Same what?
- Voltage is?
- More bulbs means?
- One break?
Level 2: Grow
- Why dimmer?
- Why all stop?
- Why series?
Level 3: Stretch
- Build.
- Compare.
- Explain.
Answers are in the answer key below. Try first, then check.
6. Apply: Science in everyday life
Explain why bulbs in series are dimmer.
Show a sample answer
Use voltage sharing.
Another one. Tell a family member one thing from this lesson. Use the words you learned.
Show a sample answer
A clear sentence that uses at least one word from Words to know.
7. Common mistakes
Fix: Dimmer.
Fix: One path.
8. Lesson summary and revision card
- I can define series circuit.
- I can predict effects of adding bulbs.
- I can explain shared voltage.
- I can state series disadvantages.
9. Check and master
Answer all 14 questions. You will see feedback after each one.
Your result appears here after you answer every question.
10. Key takeaways
- One loop only.
- Same current everywhere.
- More bulbs means dimmer bulbs.
- One break stops everything.
11. Next lesson
Next lesson: Parallel circuits introduction. Keep going with the next idea in this course.
Exam practice
These questions are written in the style of common school and international primary assessments. Try them on your own, without looking back. Then check your answers in the marking guide. The marks are shown in brackets.
- Define series circuit. [2 marks]
- Explain why bulbs get dimmer. [3 marks]
- Draw a series circuit with two bulbs. [3 marks]
- Safety rule. [2 marks]
Total: 10 marks.
Marking guide and model answers
- Components [1]; one loop [1]
- Shared voltage [1]; less each [1]; same current [1]
- Cell [1]; two bulbs [1]; one loop [1]
- Any [1]; reason [1]
Score guide: 9 to 10 = secure. 6 to 8 = nearly there, revise the parts you missed. Under 6 = work through the lesson again with a grown-up.
Printable worksheet
- What is series?
- Same what?
- Voltage is?
- More bulbs means?
- One break?
- Why dimmer?
- Why all stop?
- Why series?
- Build.
- Compare.
Homework
Draw a series circuit with a switch and two bulbs.
Answer key and marking scheme
| Question | Expected response | Marks |
|---|---|---|
| 1. What is series? | One loop. | 1 |
| 2. Same what? | Current. | 1 |
| 3. Voltage is? | Shared. | 1 |
| 4. More bulbs means? | Dimmer. | 1 |
| 5. One break? | All stop. | 1 |
| 6. Why dimmer? | Less voltage each. | 1 |
| 7. Why all stop? | Open loop. | 1 |
| 8. Why series? | One switch. | 1 |
| 9. Build. | Circuit. | 1 |
| 10. Compare. | Table. | 1 |
| Total | 10 |
Independent practice answers. Level 1: 1 One loop.; 2 Current.; 3 Shared.; 4 Dimmer.; 5 All stop.. Level 2: 1 Less voltage each.; 2 Open loop.; 3 One switch.. Level 3: 1 Circuit.; 2 Table.; 3 Sentence..
Quiz answers: 1 B, 2 C, 3 A, 4 B, 5 C, 6 A, 7 B, 8 C, 9 A, 10 B, 11 C, 12 A, Challenge 1 B, Challenge 2 C.
Mastery and remediation
| Objective | Bronze (Developing) | Silver (Proficient) | Gold (Advanced) |
|---|---|---|---|
| O1 Define series circuit | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
| O2 Predict effects of adding bulbs | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
| O3 Explain shared voltage | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
| O4 State series disadvantages | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
Courseversity badge thresholds (overall quiz score): Gold = 90–100%; Silver = 80–89.9%; Bronze = 70–79.9%. A badge is never a full record of progress.
If a learner struggles
- Find the misconception: “Adding bulbs makes them brighter.” Dimmer.
- Explain another way: use real objects, pictures or actions first, then words.
- Show a simpler example: Explain series circuits.
- Guided practice: work through one example together and let the learner try the next one.
- Reassess: use the quiz again or the worksheet.
- Move on when the learner shows Silver-level evidence independently.
For parents and guardians
In this lesson your child builds series circuits with safe cells. You do not need to be an expert to help.
- Spot series lights.
- Ask “What if one breaks?”
- Never touch sockets.
- Ask “how do you know?” after each answer, and listen.
- Praise effort, not only right answers. Mistakes are how we learn.
- Ten to fifteen minutes a day is better than one long session.
Teacher package
1–5. Objectives, prerequisites, materials, preparation, duration
Lesson objectives. Learners will: define series circuit; predict effects of adding bulbs; explain shared voltage; state series disadvantages.
Prerequisite knowledge. Grade 5 ideas: simple circuits, conductors and insulators, and magnets.
Materials. Cells, bulbs, wires, switch. Low-resource options: use chalk or charcoal on a board or wall, drawings in the sand, and objects from the classroom instead of printed materials.
Preparation. Check cells.
Suggested duration. 45–60 minutes. It can be split into two shorter sessions.
6–9. Teaching procedure, explanation notes, guided and independent activities
Introduction (5 min). Show old fairy lights going out and ask, “Why?”
Explanation (10 min). Teach series.
Guided activity (10 min). Learners build.
Independent activity (10 min). Learners compare.
Assessment and reflection (5 min). Ask each learner to say one thing they learned and how they know it.
Key questions. How many paths? What happens when one breaks?
Teacher explanation notes. Start with real objects and safe, hands-on observation. Then talk about what was seen, then draw and write. Always say “how do you know?”. Keep to the safety notes, and use local, safe materials.
10–12. Differentiation, formative assessment, common misconceptions
Support. Use real objects and pictures, short sentences and a partner. Let learners point, show or draw instead of writing. Extension. Ask learners to find a new example at home and explain how they know.
Formative assessment. Listen to learners read and explain, ask “how do you know?”, and check the independent work.
Misconceptions. “Adding bulbs makes them brighter.” Dimmer.
13–15. Assessment questions, answer keys, marking scheme
Use the quiz, the 10-mark exam practice and the worksheet on this page. All answers and marking guides are in the answer sections above. Re-check every answer before use.
16–19. Remediation, enrichment, homework, teacher reflection
Remediation. Explain series circuits. Enrichment. Look for one new example near your home or school, draw it and explain it to someone. Homework. See above.
Teacher reflection. After teaching, record: which ideas learners understood; which misconceptions occurred; which activities worked; which learners need more practice; and what to improve next time.
Sources and standards
This lesson is based on the sources below, and no official endorsement is claimed. Reference starting points: Next Generation Science Standards, Cambridge Primary Science and the IB Primary Years Programme. Where a standard code is named, it points to the official framework.
Research used to shape this lesson. Courseversity Science curriculum, Grade 6 Unit 7, topic 4; Next Generation Science Standards, energy and forces; Cambridge Lower Secondary Science, physics; IB Primary Years Programme, how the world works. These sources informed the lesson.