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Grade 4 · unit review

Review: Energy pathways and honest energy budgets

Trace energy and check that a simplified energy ledger accounts for inputs.

Download reviews and answer keys

Bring the unit skills together

Use these 4 new cases to check your reasoning. Choices are temporary and are not saved to an account, sent to staff or recorded as school grades. Download your current review choices before leaving or reloading.

Unit review questions
1. A battery powers a paper-model buzzer that emits sound and warms. Which pathway fits?
2. A no-storage-change device receives 50 units and sends 18 as light. Its only other output is thermal. How much is thermal?
3. With equal 60-unit inputs, model P gives 15 light units and Q gives 21. Which meets a lighting goal with more useful output?
4. A device receives 24 units, transfers 7 light and 13 thermal units out, and has no other transfers. What is its stored-energy increase?

The download contains your current choices and any checked feedback. Keep the separate transfer-task work in your own document; downloading its instructions does not mark it complete.

Use the skills in a new task

Complete a design note for a fictional sign light. Model A receives 30 units and outputs 9 light and 21 thermal units with no storage change. Model B receives 30 and outputs 12 light and 16 thermal units; 2 units increase its stored energy. Trace the battery pathway, check both ledgers, choose for light output, and explain B’s storage entry.

Work on paper or in your own document. Explain the choices you made.

  • Describe stored chemical → electrical → light and thermal transfers.
  • Show A: 9 + 21 = 30 and B: 12 + 16 + 2 = 30.
  • Choose B’s 12 light units for the same input.
  • Explain the 2 stored units without saying energy vanished.
Compare with a model response

Battery chemical energy supplies electrical energy, then light and thermal transfers. A balances with 9 + 21 = 30. B balances with 12 + 16 + 2 = 30. I choose B for 3 more light units at the same input. Its outputs total 28 because 2 units increase energy stored inside it, as stated in the supplied model.

A different response can also meet the criteria. Compare the evidence and reasoning, rather than copying the wording.