# A changed start

Made-up practice story.

A fictional plan uses a covered tray with 40 mL inside and an uncovered tray with 20 mL outside. Can it isolate the cover effect? Repair it.

## Make something useful

Use a small caption, arrow model, table or spoken explanation for this exact question. Keep the supplied story beside you.



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<summary>Grown-up help</summary>

**Worked practice:** No. Match starting volume and place (as well as tray and review duration), then change only the cover status. Do not predict a fixed visible loss from the repaired plan.

[Complete Day 36 plan](../lessons/day-36.html). This is ordinary practice, not a held assessment source.

[Checked process facts and limits](../references/PRIMARY-READING.html) · F1

</details>