# Learner lab record: Closed-cycle Casimir work record

Course: Why empty space is not simple

Name: ____________________  Date: ____________________  Group: ____________________

## Investigation question

Why does measurable work during plate approach not by itself create a repeatable net-energy source?

## Setup

Use the closed-cycle Casimir ledger. Record approach output, ideal separation work, actuator overhead, control input, and final net for the same returned plate state.

## Variables

| Variable | Role | Unit |
| --- | --- | --- |
| Plate area and initial gap | geometry inputs | cm² and nm |
| Gap closure | independent | % |
| Approach and reset work | dependent | J |
| Actuator and control costs | system inputs | % and J |

## Predict before changing controls

1. Predict the reversible net when overhead and control both vanish.

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2. Predict how a smaller final gap changes the ideal interaction energy.

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## Observation table

| area | initial gap | final gap | approach work | reset + overhead | control | net |
| --- | --- | --- | --- | --- | --- | --- |
|   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |

## Analyze

1. Which two terms cancel in the reversible limit?

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2. Which costs make the full cycle negative?

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3. What remains established even when net output is negative?

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4. List two real-material corrections missing from the ideal expression.

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## Evidence-bounded conclusion

The approach delivered ___ J, but returning the plates and controls required ___ J, so the complete-cycle net was ___ J.

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