You will learn
- Trace energy flow.
- Explain the ten percent rule.
- Draw an energy pyramid.
- Explain why chains are short.
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
- Energy flows one way.
- Only about ten percent is passed on.
- Most energy is lost as heat.
- Chains are short because energy runs out.
Words to know
the movement of energy through an ecosystem
a diagram showing energy at each level
a feeding step
the mass of living material
1. Discover: The grass and the lion
A field of grass captures 10,000 units of the Sun’s energy. A zebra herd gets about 1,000 units, and a lion only about 100. “Each step loses most of the energy as heat,” says the ranger. “That is why there are fewer lions than zebras.”
Think: Why are there fewer top predators?
2. Understand: Energy flow
Idea 1: One way
Sunlight enters through producers and moves up the chain. Energy is not recycled; it ends as heat lost to space.
Idea 2: Ten percent
Only about ten percent of the energy at one trophic level reaches the next. The rest is used for life processes or lost as heat.
Idea 3: Pyramids
An energy pyramid is widest at the bottom. Because each level has less energy, there are fewer animals higher up, and chains rarely exceed five links.
3. Worked examples
Example 1 (I show you): Calculate
10,000 units.
- 10 percent.
- 1,000.
- Next level.
Answer: 1,000 units pass on.
Example 2 (We do it together): Draw
Pyramid.
- Wide base.
- Producers.
- Narrow top.
Answer: Wide at bottom.
Example 3 (You try): Explain
Few lions.
Show the steps and answer
- Less energy.
- Loss.
- Short chain.
Answer: Little energy remains.
Did you know?
A single great white shark needs thousands of fish eaten across the food chain before it, supported by an enormous base of plankton.
Why this matters
Energy flow explains why ecosystems need many more plants than animals.
4. Explore: Pyramid model
Stack cups or draw bars for 10,000, 1,000, 100 and 10 units to model energy at each level.
- Draw bars to scale.
- Label levels.
- Add example organisms.
- Explain the loss.
Think about it: what did you notice?
What did you notice? The top was tiny compared with the base.
5. Practise
Say it in a sentence
Use these starters when you talk about the lesson. Say them out loud.
- ___ flow is the movement of energy.
- About ___ percent passes on.
- An energy ___ is widest at the base.
- ___ is the mass of living material.
Guided practice
Question 1. Where does energy start?
Sun.
Question 2. How much passes on?
Ten percent.
Question 3. What shape is the pyramid?
Wide base.
Independent practice
Level 1: Start
- Where does energy start?
- How much passes on?
- What shape is the pyramid?
- Where does energy go?
- Is energy recycled?
Level 2: Grow
- Why short chains?
- Why few lions?
- Why need many plants?
Level 3: Stretch
- Draw the pyramid.
- Calculate energy.
- Explain.
Answers are in the answer key below. Try first, then check.
6. Apply: Science in everyday life
Explain why food chains are short.
Show a sample answer
Use the ten percent rule.
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: One way.
Fix: Fewest.
8. Lesson summary and revision card
- I can trace energy flow.
- I can explain the ten percent rule.
- I can draw an energy pyramid.
- I can explain why chains are short.
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
- Energy flows one way.
- Only about ten percent is passed on.
- Most energy is lost as heat.
- Chains are short because energy runs out.
11. Next lesson
Next lesson: Matter cycling 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 energy flow and biomass. [2 marks]
- Calculate energy for three levels. [3 marks]
- Draw an energy pyramid. [3 marks]
- Safety rule. [2 marks]
Total: 10 marks.
Marking guide and model answers
- 1 each
- 1 each
- Shape [1]; labels [1]; numbers [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
- Where does energy start?
- How much passes on?
- What shape is the pyramid?
- Where does energy go?
- Is energy recycled?
- Why short chains?
- Why few lions?
- Why need many plants?
- Draw the pyramid.
- Calculate energy.
Homework
Explain at home why there are few lions.
Answer key and marking scheme
| Question | Expected response | Marks |
|---|---|---|
| 1. Where does energy start? | Sun. | 1 |
| 2. How much passes on? | Ten percent. | 1 |
| 3. What shape is the pyramid? | Wide base. | 1 |
| 4. Where does energy go? | Heat. | 1 |
| 5. Is energy recycled? | No. | 1 |
| 6. Why short chains? | Energy runs out. | 1 |
| 7. Why few lions? | Little energy. | 1 |
| 8. Why need many plants? | Support others. | 1 |
| 9. Draw the pyramid. | Diagram. | 1 |
| 10. Calculate energy. | Sums. | 1 |
| Total | 10 |
Independent practice answers. Level 1: 1 Sun.; 2 Ten percent.; 3 Wide base.; 4 Heat.; 5 No.. Level 2: 1 Energy runs out.; 2 Little energy.; 3 Support others.. Level 3: 1 Diagram.; 2 Sums.; 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 Trace energy flow | 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 Explain the ten percent rule | 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 Draw an energy pyramid | 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 Explain why chains are short | 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: “Energy is recycled in ecosystems.” One way.
- Explain another way: use real objects, pictures or actions first, then words.
- Show a simpler example: Explain energy flow.
- 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 studies energy flow. You do not need to be an expert to help.
- Share ten counters down a chain.
- Ask “Why do top animals have few?”
- Respect views.
- 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: trace energy flow; explain the ten percent rule; draw an energy pyramid; explain why chains are short.
Prerequisite knowledge. Grade 4 ideas: habitats, simple food chains, producers and consumers, and adaptations of living things.
Materials. Cups, paper. 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. Gather cups.
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). Pass 10 counters down and ask, “Why so few left?”
Explanation (10 min). Teach energy flow.
Guided activity (10 min). Learners model.
Independent activity (10 min). Learners explain.
Assessment and reflection (5 min). Ask each learner to say one thing they learned and how they know it.
Key questions. How much passes on? Why?
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. “Energy is recycled in ecosystems.” One way.
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 energy flow. 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 5 Unit 8, topic 7; Next Generation Science Standards, ecosystems: interactions, energy and dynamics; Cambridge Primary Science Stage 5, biology: living things in their environment; IB Primary Years Programme, sharing the planet. These sources informed the lesson.