Skill: write-like-james @ b0fa825 · the build: write-lesson, write-mcqs, write-video-script, review-lesson (two blind reads and a re-read), review-figures, review-accuracy @ b0fa825
Topic 2 "How to run a fair test" — your read (2 October 2026)
Skim first
The lessons in teaching order, each with its one rule sentence; then the intro script; then the question types. The review page follows.
The lessons and their rules
| Lesson | Atom | Rule sentence |
|---|---|---|
| L01 A question you can test | SR4-001 | Try something out and watch what happens. That is a question you can test. |
| L02 The one thing you change | SR4-002 | Change one thing on purpose. It is the thing your question asks about. |
| L03 Keep everything else the same | SR4-003 | The one thing you change. Everything else must stay the same. |
| L04 What you measure to see the result | SR4-004 | Measure the thing your question asks about. Measure it after the change. |
| L05 Fair test or unfair test? | SR4-005 | Only one thing changed. Everything else stays the same. That is called a fair test. |
| L06 Test friction on different floors | FOR4-004 | Write down the question. The one thing you change. What stays the same. What you measure. |
The intro script (115 words, about 58 s)
Here's Miss Alvarez's class in the school hallway, and Maeve has a toy car and a small ramp. She lets the car go on the tile, and it rolls a long way. Then she moves the ramp onto the carpet, and this time the car stops after a short way. Felipe says that proves it: the tile lets the car go farthest. But Niall is not so sure. So how does the class find out for sure, in a way nobody can argue with? To find out, we will look at what you change, what you keep the same, and what you measure. Okay, so are you ready to run a test everyone can trust?
The question types (from TYPES_G4T02.md)
- Type 1: Can the class test it? Four questions; pick the one that names something to try out and watch (or the one that does not).
- Type 2: Say it so it can be tested: a vague question ("which is the best?") and four rewrites, one of which names something to try out and watch; the hard item asks what to do FIRST with a question nobody can test.
- Type 3: The one thing changed: a described test (or its question) and four things in it; pick the one changed on purpose.
- Type 4: Keep everything else the same: which of four things must stay the same; which thing changed that should have stayed the same; the hard items SELECT THE TWO things that must stay the same (multi).
- Type 5: What you measure: four measurements, one of which is the thing the question asks about after the change; the hard items give the reason a measurement fails, or chain result → tool.
- Type 6: Fair test or not: four described tests, pick the one that changed only one thing (the stem never prints the term); or a test that is not fair and the two things that changed.
- Type 7: Name the test: the term by recognition among sister names (easy), then TYPED from a described case (hard).
- Type 8: The plan: which line goes under a heading; which question fits a plan; which line is missing or fails to name a measurable result (a drawn board); the hard item REPAIRS a plan.
- Type 9: Read the results: a drawn results table; which surface; the hard items TYPE the difference between two cells, or turn the table back into the plan's one-line answer.
- Type 10: Judge the result or the claim: the verdict is in the stem; the options are four single-statement reasons.
One investigation from question to result: which floor lets the same toy car slide farthest? Six lessons: a question you can test; the one thing you change; keep everything else the same; what you measure; fair test or unfair test (the term coined here); plan the friction test and read its results (tile 180, wood 150, carpet 40 centimeters, as Topic 1 predicted). Every key agreed by two cold readers; the one attached question both rejected was rewritten and re-read clean. The figure review and the guidance-and-accuracy review are applied. Pictures are placeholders until you answer.
The two the reviewers put to you (built as recommended)
1. When a child types the term, is "fair" alone accepted?
Every typed stem prints "What kind of test is this? Type its name", so "test" is on screen and "fair" completes it; the why prints the whole term.
Recommendation: accept "fair" alone.
Accept / require "fair test"
2. Is a typed hard tier of 3 items in 13 right for this topic?
Your 29 September ruling: typing stands for a recalled coined term or a produced number, not for judgements. This topic's produceable things are the term and a table subtraction; its judgement items are verdict-in-stem, single-reason MCQs.
Recommendation: yes.
Yes / more typed items
The lessons
3. L01 A question you can test — "which floor is the best?" against "which floor lets our toy car slide farthest?": only a question you can answer by trying something out and watching can be tested. page
4. L02 The one thing you change — the same ramp and car carried from tile to wood to carpet: the floor is the one thing changed on purpose, because it is what the question asks about. page
5. L03 Keep everything else the same — Felipe gives the car a push on the carpet, and nobody can tell whether the floor or the push made the difference. page
6. L04 What you measure to see the result — how far the car slid, in centimeters, with a tape measure from the ramp's foot; the measurement matches what the change did. page
7. L05 Fair test or unfair test? — two bean plants, more water and more light at once: two things changed, so it is not a fair test. A test where only one thing is changed, and everything else stays the same, is called a fair test. page
8. L06 Test friction on different floors — the plan on the board, the three runs, the results table and the one-line answer. page
Applied without asking
One running investigation re-set in every first beat, fresh quiz scenes; "fair test" the only term, glossed at the coin as "only one thing was changed"; no "variable" words; Grade 3's tools recalled by one item each ("a digital scale"); Topic 1's rule recalled word for word ("has less friction"); the rejected attached stem rewritten so the one change is the test's own question; two bank items that had a second fair test among their options fixed; the L05 video gains a fair-test example before the coin; summary before practice; 57-item bank, 9 to 10 per atom; "run" for "go"; five picture placeholders with briefs.
Also on the site
Topic intro and poll · summary and three questions · mixed practice · the PP100 bank · the blueprint · the type sheet
After you answer
Nothing on the page changes either way; the picture pass starts, and the eight-video batch goes with Topic 1's on your word.