Hand each group the Design Brief they completed earlier in this project. Have the shared junk-modelling kit already set out on group tables, but do not start building yet.

Key questions: What problem is your prototype solving? Who is it for? What will count as success when we test next time?

Keep the hook light: reconnect to purpose and pride in the plan. Save kit talk and method for the next steps.

Nature of STEM: name that engineers build prototypes from plans, then adjust when real materials behave differently from the sketch. That is normal professional work, not a mistake.

Three short board lines to project (these match the pupil screen):

1. Name the user and one success criterion.
2. Point to the main shape on your sketch.
3. Follow the brief; jot any plan change (what + why).

Use the full table below for yourself while groups re-read their briefs. Do not project the full table.

Worked model (do this live, about two minutes): Hold up a scrap of card and a short piece of string. Say: I wonder if this flap will stay shut with tape alone. Try tape; let it peel. Say: I predict string will grip better across the join. Tie the string. Say: I observed the flap stays shut. I think our plan should change from tape to string on this join, and I will jot that on a sticky note now. Show that a plan change is evidence, not failure. Fuller definitions live in this model and the table above, not in a dense pupil glossary block.

Misconception to head off: pupils sometimes treat the sketch as a picture to copy exactly, even when the real material will not hold. A brief is a guide; a recorded change that keeps the user need is good engineering.

Quick purpose check (keep light — do not run a full round-the-room restates gate): while groups re-read, listen in and spot-check that each group can name the user and one success criterion. If a group cannot, pause that group only and help them find those on the brief before materials leave the tray. Save the main-shape check for the first minute of the build as you circulate.

Do not spend the whole six minutes on oral restates from every group. The live plan-change model and a light purpose check both need to fit without racing.

Before the lesson

• Return each group's Design Brief from earlier in this project.
• Set out one shared junk-modelling kit per group (same kit for every problem on the curated list), including two pairs of scissors per group on the table.
• Pre-cut path (so adult cuts do not steal circulating time): before the lesson, pre-cut common thick pieces groups are likely to need (for example wide base strips, door-length card for draught-stoppers, tube slits started with an adult cut). Leave a small labelled tray of these on each table. During the build, only rare one-off thick cuts need an adult; if a second adult is available, station them for cuts while you coach.
• Remind the class: scissors stay on the table under adult eye-line; an adult still makes any remaining difficult cuts in thick card or plastic.
• Clear floor space so tall builds (shelters, stands) have room to stand.
• Put a small pad of sticky notes (or spare journal space) with each group for mid-build plan-change jots.

During the build

Circulate and coach, do not rebuild for them. In the first minute, check any group you did not hear name the main sketch shape. Ask: Which part of the brief are you working on now? What is the join doing — pushing or pulling? What would make this unfair to your success criteria if we tested it tomorrow?

In-build capture cue (say this as they start and again mid-way): each time the plan changes, one pupil jots on a sticky note or the edge of the journal page: what changed + why. Step 4 is finishing those notes, not reconstructing memory from a busy build. Keep the ordered list visible on the IWB so the jot line stays in sight.

Kit-compatible problems (from earlier in this project): a cover or shelter for a bug hotel or seed trays; a barrier to stop balls rolling into a flowerbed; a stand or holder to display books; a draught-stopper for the classroom door. Every group builds from the same kit so materials stay fair.

Look-fors:

• The prototype matches the main idea on the brief (same job, same user).
• Joins are deliberate (tape, string, slots) rather than piles of loose card.
• Groups test stability gently before adding decoration.
• At least one pupil in each group can name a plan change or say the plan held, with a jot already started.

If a group is stuck: send them back to the success criteria, not to a new invention. Suggest one structural idea they already know (wide base, triangle brace, tube instead of flat sheet) and let them choose.

Differentiation: less confident groups may build a simpler version that still meets one success criterion; more confident groups can add a second feature from their brief (a hinge, a removable lid, a wider base) once the main structure stands.

Safety: two pairs of scissors per group on the table under adult eye-line; adult makes remaining difficult cuts in thick card or plastic; no running with materials; stand clear if a tall structure tips.

This is the paper recording beat for the lesson. Pupils write and draw on the Investigation Journal page only — nothing is typed into the platform.

Expected journal fields (what the provided Investigation Journal page asks for):

• Build notes — what they made and how complete it is (drawing allowed instead of full sentences).
• Plan change or plan held — what changed + why, or clear evidence the plan held.
• User-need line — one sentence linking the prototype to the user on the brief.

Keep the demand to these three fields only so mixed writers can finish in 12 minutes after a long make. Transfer sticky-note jots onto the journal page; keep or discard the stickies as you prefer. Do not invent extra layout boxes for them.

Individual pages, group talk: each pupil completes their own Investigation Journal page. They discuss as a group and share the sticky-note jots, then every child records their own three fields. Look-fors are met when every pupil has a concrete page, not when only one shared sheet exists for the group.

Teacher model if needed: on the board, think aloud one line only: We changed the base from a flat sheet to a folded triangle because the stand wobbled — that keeps the book-holder upright for the reader. Then send them to their own pages.

Support: allow drawing plus short labels instead of full sentences for any field; a stem on the board helps (We changed ___ because ___ / The plan held because ___).

Check while circulating: every pupil has at least one concrete build note and either a plan change with a reason or a confirmed "plan held" with evidence, plus a user-need line. Vague lines such as "it was hard" need a prompt: Which join? What did you try next?

Keep prototypes on the group table labelled with group names. They stay at school for the test and improve session next time.

Display-only design talk. No typing and no extra written reflection beyond what is already on the journal page.

Take three or four quick group shares. Revoice engineering language: You changed the join because the material could not take the pull — that is a plan change based on evidence.

Common sticky points: groups that decorated before the structure stood; groups that abandoned the brief for a new invention; groups with no recorded plan change even though the build clearly drifted. Address gently and link back to the user need.

Remind the class that next time they will test against the success criteria on the Design Brief, make one improvement, re-test and present.