Energy transfer budget
Audit a deliberately simplified energy-flow model and its limitations.
Adult planning suggestion: about 9–12 · Logic & rule checking
- Players
- 1–4 with adult support
- Time
- 15–25 minutes
- Materials
- Four level cards and 1000 paper energy units
Prepare
Use a stipulated model with 1000 energy units at producers. At each transfer exactly 10% of the previous level becomes the next level’s budget. The remaining 90% is classified as not transferred onward in this model. This fixed ratio is a teaching assumption, not a universal measured ecosystem efficiency.
Play
Write successive budgets for producers, primary consumers, secondary consumers and tertiary consumers. Multiply the current budget by 0.1 at each step; do not subtract a fixed 100 every time.
Worked example
The budgets are 1000,100,10,1. The amounts not transferred at successive steps are 900,90,9. Their sum 999 plus the final 1 equals the original 1000, so the ledger balances.
Finish and check
Do not add 1000+100+10+1 and call that new energy created: the levels represent successive transfers of the same starting budget. Nor does the diagram measure the number of animals or promise that every real chain has these exact values.
Adaptation and limits
Finish after a partner checks all multiplications and the original-budget accounting. A separate 20% model gives 1000,200,40,8; label it a changed assumption, not a correction based on field data. Use labeled scrap paper instead of buying counters.
Purpose, observation and provenance
Within this activity: Audit a deliberately simplified energy-flow model and its limitations.
Check the three transfer multiplications and reconcile the residuals plus final budget with the original 1000 units.
Our rules, examples and printable diagrams are separately prepared. The earliest inventor of the broader mechanism is not established here.
OpenStax: Energy Flow through Ecosystems — Reference supports the stated concept; our fictional numbers, instructions and paper diagrams are independently prepared, not reproduced teaching pages.
Secondary practice: Cooperation and explaining a check.
For a class of 30, use ten groups of three. Prepare one player-material set per group and keep the host key with the adult. Rotate operator, recorder and checker after each worked example; a reader or scribe may help without choosing answers. Avoid public ranking or diagnostic labels.
Age bands are planning suggestions. Background references may address older learners and do not validate suitability for this age band. Goals describe observable actions, not measured long-term gains or institutional endorsement.
Free alternative: Copy the supplied grids, labels and cards onto reused paper. No specialist product is needed. Adults may prepare pieces or act as a scribe.
Printable materials
Preview at 100% scale, with browser headers and footers off. Cut with suitable help. Keep host keys separate. This is a manual tabletop kit, not an online opponent, automatic judge or solver.
Rules to keep beside the materials
- Use a stipulated model with 1000 energy units at producers. At each transfer exactly 10% of the previous level becomes the next level’s budget. The remaining 90% is classified as not transferred onward in this model. This fixed ratio is a teaching assumption, not a universal measured ecosystem efficiency.
- Write successive budgets for producers, primary consumers, secondary consumers and tertiary consumers. Multiply the current budget by 0.1 at each step; do not subtract a fixed 100 every time.
- The budgets are 1000,100,10,1. The amounts not transferred at successive steps are 900,90,9. Their sum 999 plus the final 1 equals the original 1000, so the ledger balances.
- Do not add 1000+100+10+1 and call that new energy created: the levels represent successive transfers of the same starting budget. Nor does the diagram measure the number of animals or promise that every real chain has these exact values.
- Finish after a partner checks all multiplications and the original-budget accounting. A separate 20% model gives 1000,200,40,8; label it a changed assumption, not a correction based on field data. Use labeled scrap paper instead of buying counters.
Energy transfer budget — player materials
| Level | Budget | Transferred onward | Not transferred |
|---|---|---|---|
| Producer | 1000 | ||
| Primary | |||
| Secondary | |||
| Tertiary | — | — |
| Changed assumption | Budgets |
|---|---|
| ________ | ________ |
| ________ | ________ |
Host check — keep separate
10% budgets 1000,100,10,1; residuals 900,90,9;20% gives 1000,200,40,8.
Examples are stipulated model cases, not measured experimental or learning outcomes.
Related activities
Activity library · Shared threshold project: rules and printable materials