1 - Getting Started ~5 mins
Today we load our builds live. No claims, only numbers. Which shape or join earned the gain, meaning which change actually made the number go up? For example: held 2 books, then 5 after a brace.
Have every group's finished build and its real load ready on side tables before the lesson. Ask one volunteer group to rest a light load on their build for a moment, then take it off. Keep the hook short: curiosity about measured proof, not a full demo.
Key question: If two groups both say their build is strong, how do we know which change really worked?
Misconception to head off: pupils may treat a neat finish or a confident voice as proof. Steer them back to before-and-after numbers from the project journal.
2 - Evidence, Not Opinion ~8 mins
You will load your build so the class can see the numbers. That measured result is evidence, not a feeling that it is stronger. Pick the one structural idea (the shape or join) that made the number go up. The live load-and-explain is your showcase.
What will you load, and which one idea made the biggest difference?
| Concept | Why it matters | Example |
|---|---|---|
| Evidence — a measured result you can show, not a feeling or a guess | Engineers prove an improvement with a number, so other people can trust the claim | "It held 3 books, then 6 after the brace" is evidence; "it looks tougher" is not |
| Structural idea — a shape or join choice that carries load better | The module's science decides whether a build works: triangles, span shape, and joins that hold | A diagonal strip turns a floppy square into triangles that will not lean |
| Showcase — a live load demo with a short evidence-led explanation | Showing the load in front of the class beats describing the build from memory | Loading a coat hook slowly while naming the gusset that stopped the peel |
Worked showcase model (teacher coaches one volunteer group through one full cycle aloud before groups prepare):
Use that group's real build and load. Coach them to speak the cycle so the class hears the pattern:
I wonder which idea made this build hold more. I predict [their chosen brace, join, or span] will be the difference-maker because [their small-test clue]. I test by loading the real load slowly and safely. I observed [after number]; before the change it held [before number]. I think [named shape or join] stopped the lean, sag, or peel, so those two numbers are the evidence.
Do not set up a separate teacher demo build. The volunteer group's build is the model; lesson materials already include group builds and loads.
What good looks like: each group can name one shape or join, say the before number and the after number, and point to the part that did the work while the load is on.
Misconception: pupils list every material they used. Press for the single idea that changed the result.
3 - Prepare Your Evidence ~7 mins
Open your Investigation Journal to the project pages. Find the load your build held before the change and after the change. Agree the one shape or join you will name. Practise a short live load with your group only if your numbers are already written.
Before groups start: each group needs its build, the real load it was designed for (books, tablet, coats, or the weights used earlier in this project), and the journal pages from the design-build arc (DesignBrief, InvestigationLog, PrototypeEval / ResultsAndConclusion).
Triage order for these 7 minutes (keep this order):
- Numbers first (about 2–3 min): find before and after load figures in the journal and check they match what the group will say.
- One idea second (about 1–2 min): agree the single shape or join named as the difference-maker.
- Practise load last, and only if numbers are already written (remaining time): one slow safe load. Not a redesign.
Fallback if numbers are missing: one careful load now; record today's figure as the after result, with an honest note that the before figure came from memory or the small test. Do not let a full re-test eat the whole slot. If time is tight after recovering numbers, skip the practise load and go straight to naming the idea.
Look-fors while you circulate:
- Before and after numbers are written and match what the group will say
- Only one structural idea is chosen as the difference-maker
- The person who loads stands clear of a failing edge and loads slowly
- Every pupil in the group can say the numbers, not only the spokesperson
Differentiation: if a build is too fragile for a full class demo, agree a lighter safe load and say so openly.
Safety: load low and slowly; stand clear if anything sags; an adult steadies tall or tippy builds.
4 - Live Load Showcase ~18 mins
Each group loads its build in front of the class. Say the job it does, the number it held before, the one change you made, and the number it held after. Point to the shape or join that made the number go up while the load is still on.
If you are watching: listen for the before number, the one change, and the after number. Be ready to say whether the numbers match the claim.
Setup: clear a front table or floor space. Groups come up one at a time with build and load.
Hard per-group ceiling: about 90 seconds speaking and loading, then one quick class question only. Aim for every group to present inside 18 minutes.
Group-count contingency: with up to 6 groups, keep 90 seconds plus one class question each. If more than 6 groups, drop the post-demo class question to one volunteered observation after every second group, or pair two quick loads then take questions on both. Do not run a written or round-robin peer-feedback pass during the showcase; it will overrun the slot.
Fold the watchers in (teacher questions only): after each load (or pair of loads) ask What was the structural idea? and Did the numbers match the claim? Watching is real participation; do not invent a separate desk task.
Sentence stems to offer if a group freezes: Our job was… Before the change it held… We changed… After that it held… The idea that made the difference was…
Nature of STEM weave: engineers show evidence rather than assert. Same idea as the engineers who check a bridge or the roof trusses above a PE hall: they trust numbers under load, not a confident claim.
If a build fails during the demo: treat it as useful data. Ask what gave way first and which module idea would fix it. Failure under load is information, not embarrassment.
5 - Walk and Steal One Idea ~10 mins
Walk the other builds. For each one you visit, look at the shape or join under the load. On your Investigation Journal page, answer these three short questions:
- What held on the build you liked most, and what number proved it?
- Which one structural idea would you steal for a new build, and why?
- How did that group show evidence instead of only describing the build?
Before the Lesson
Leave builds on tables with a light safe load still in place where possible, or with the load beside the build and the after number already visible from the showcase. Pupils record only on their Investigation Journal page (the reflection questions match the board). No sticky notes and no second sheet.
Suggested Timing
About 8 minutes circulating in small groups, 2 minutes back on the carpet to hear three stolen ideas aloud.
Teaching Tips
Ban vague praise such as it looks nice. Push for reusable structural language: triangle brace, arch feet taped down, gusset at the join, rolled tube post, split-pin pivot only where movement is wanted.
Recording: Investigation Journal page only. Prompts on the board are the same three questions as the journal. This is paper notes plus spoken share-out, not typing into the platform.
Common pitfall: pupils copy decorations. Redirect to the load path: where does the weight go, and what stops the lean, sag, or peel?
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