Year 7 Technology · 2026
Week 7 · Lesson 14

Mirror the truss — build the second side

Week 7 · 75 minutes · Year 7 Technology (Mandatory) · Bridge It

TE4-3DP

🎯 Learning intentions

  • I can build a second truss that mirrors the first in shape and size.
  • I can compare two trusses and identify small differences.
  • I can submit Part A of my Assessment Task (Design Folio) on time.

✅ Success criteria

  • Truss #2 is complete and matches truss #1 in key dimensions.
  • Build journal has photo 4 with both trusses side-by-side.
  • Part A Design Folio submitted to Google Classroom before the bell.

Do Now · 5 min

PART A DUE END OF THIS LESSON. Open your folio on your laptop. Quick self-check:

  1. Cover page with both names, class, date?
  2. Design brief with 3+ sentences?
  3. 6 annotated research sources?
  4. 3 thumbnail sketches with pros/cons?
  5. Plan + elevation + isometric drawings?
  6. Materials list + WHS risk + build schedule?
  7. Pair agreement signed?
Any missing item — prioritise it in today's You Do time.

I Do · ~10 min Teacher demonstration

Teacher demo — mirroring a truss.

  1. Lay truss #1 flat. Use as a reference template.
  2. Cut new base chord same length as truss #1's.
  3. Repeat the top chord + verticals + diagonals process — but INSPECT each stage by laying it over truss #1 to compare.
  4. Any difference > 3 mm — adjust before glue sets.
Why symmetry matters: your two trusses form the sides of one bridge. If they're different shapes, the deck won't sit flat and load won't distribute evenly — weak bridge.

We Do · ~15 min Guided practice

Together, we compare one team's truss #1 vs truss #2 under Ms Gao's eye. Identify 3 differences. Ms Gao models how to fix one of them by adding a small gusset plate (tiny patch of extra stick).

You Do · ~35 min Independent pair work

Split time between building and folio finishing (35 min).

  1. Build truss #2 using truss #1 as reference.
  2. If truss #2 is ahead of schedule, spend remaining time on folio polish.
  3. Take photo 4 — both trusses laid side by side.
  4. Before the bell: submit Part A to Google Classroom. File name: Y7TECH-Bridge-[TeamName]-PartA.pdf.
  5. Verify submission — screenshot of the 'Submitted' status in Classroom, save to build journal.

Differentiation

🪜Support

Pre-cut components for truss #2 matching truss #1 exactly. Teacher verifies submission with student.

🎯Core

Build truss #2 independently + submit Part A independently.

🚀Extension

If truss #2 is complete early, start deck planning — measure and cut deck cross members ahead of L15.

Exit Ticket · 5 min

  1. Did you submit Part A? (Show Ms Gao your Classroom screen.)
  2. How symmetrical are your two trusses — very / mostly / slightly / not at all?
  3. What's one thing you could do to make them more identical?

📚 Resources for this lesson

Before you leave Quick check-in

🚩 Stuck or confused?

Click this button to flag to Ms Gao that you need a 1-to-1 next lesson. Your message is copied — paste it into a Google Classroom private comment.

📄 Export journal so far

Save your journal as a .txt file to upload to Google Classroom for Ms Gao's Friday review.

📓 Open journal + export