# Day 32 · A puddle gets smaller

**Start:** “The puddle is smaller. Choose a possible explanation.”

**Purpose:** Explain evaporation as liquid water becoming invisible water vapour; distinguish explanation from observation.

## Prepare

Read today's complete model and two contexts before the session. Paper, a pencil and the full written picture words are sufficient. Optional actual water work follows [ordinary preparation](../teacher/PREPARATION.html); the teacher chooses suitable familiar materials/instruments. Use today's three routes without assigning a fixed learning-style label.

## Run the session

1. Reconnect: return to a liquid water place. Introduce the supplied picture pair “same marked patch: wet earlier, dry later”; the drawings are made-up evidence.

2. Model: “I can see less liquid water. Some water could have become invisible water vapour. That change is evaporation.” Contrast what was shown with the proposed cause; other routes such as soaking need other clues.

3. Try: place liquid-water and vapour-in-air cards with the evaporation link. Optional teacher-managed tiny room-temperature tray observation begins with an actual dated starting record and remains open if no clear change occurs.

4. Compare: use a towel patch and a rain puddle as different contexts. Less visible water alone cannot establish how much evaporated, exact timing or that no water soaked/spilled.

5. Make: produce a two-state explanation. Use words, arrows, two spoken lines or the first Water Trail link. Show vapour as labelled empty-air space, not a cloud.

6. Exit: “Evaporation changes __ into __. One clue I would look for is __.” Accept scientifically equivalent wording.

## Three ways in

### Two-card switch

Use labelled liquid / invisible vapour cards and an evaporation arrow; reposition by eye or ask a helper to move them.

**Worked ordinary reasoning:** Liquid water can become invisible water vapour in air.

### Observation notebook

Observe an adult-approved tray from a dry safe place; draw or dictate what is actually visible at each review time. Keep explanation in a separate line.

**Worked ordinary reasoning:** I recorded the starting mark. I have not yet seen a clear change; I cannot invent a final amount.

### Clue editor

Edit “the water vanished forever” into a useful supplied-picture caption; pick or compose words instead of handling water.

**Worked ordinary reasoning:** There is less liquid water in the picture. Evaporation is a possible explanation; the drawing alone cannot rule out soaking.

## Look and choose the next teaching

Liquid-to-gas meaning and an observation/explanation distinction; no requirement to see vapour.

If vapour is drawn as drops, reteach the two state labels and the invisible-gas limit before condensation.

## Today's complete resources

[A02 · whole labelled picture](../aids/A02.svg) · [A02 · complete picture words](../aids/A02-alternative.html)

[A05 · whole labelled picture](../aids/A05.svg) · [A05 · complete picture words](../aids/A05-alternative.html)

[C03](../contexts/C03.html)

[C04](../contexts/C04.html)

[H02](../home/H02.html)

[X02](../projects/X02.html)

[Short child start](../child/day-32.html) · [Written read-aloud](../narration/day-32.html) · [Water Trail and paper](../interactive/index.html)

Partial opportunities: AC9S4U02, AC9S4I01, AC9S4H01 · [Full mapping and limits](../teacher/CURRICULUM.html)

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<summary>Grown-up help</summary>

Allow source access and neutral reading/support. Keep supplied story, child response, helper actions and actual observation distinct. Use component-specific criteria after the response, not a model answer before it. Suggested six-move timing 4/7/12/8/6/3 minutes may be split; there is no performance timer.

Modified from [Year 4 Science alignment](https://www.qcaa.qld.edu.au/downloads/aciqv9/science/curriculum/ac9_science_yr4_as_cd_alignment.pdf), [standard elaborations](https://www.qcaa.qld.edu.au/downloads/aciqv9/science/assessment/ac9_science_se_yr4.pdf) and [Years 3–4 techniques and conditions](https://www.qcaa.qld.edu.au/downloads/aciqv9/science/assessment/ac9_science_tc_yr3-4.pdf), © State of Queensland ([QCAA](https://www.qcaa.qld.edu.au/copyright)) 2023, covered [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/) with exceptions. Our task criteria are original; these are not official A–E bands. Actual folio and on-balance professional judgment remain necessary.

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