Scaled technical drawing — plan + elevation at 1:5

Do Now · 5 min

Scale recall from Term 1 L10 — answer in your folio:

1. If my real bridge is 400 mm long, at 1:5 scale how long is the drawing? (hint: divide by 5)
2. If my drawing is 25 mm wide at 1:5 scale, how wide is the real bridge?

I Do · ~10 min Teacher demonstration

Teacher models drawing a scaled bridge. Steps:

1. Tape A3 grid paper to the desk. Orient landscape.
2. Draw a title block in the bottom-right: project name, team name, scale (1:5), date.
3. Divide the page in half — top half for ELEVATION (side view), bottom half for PLAN (top view).
4. Mark starting point (0, 0). Our bridge is 450 mm long → at 1:5 → 90 mm on paper.
5. Draw the top chord as a straight line 90 mm long. Draw the bottom chord 30 mm below it.
6. Mark vertical members every 15 mm. Draw them.
7. Add diagonals for your chosen truss type.
8. Add dimension lines on every member — use technical lettering (UPPERCASE, same height).

We Do · ~15 min Guided practice

Together, we measure three real lengths and convert to 1:5 scale:

• Real bridge 450 mm → Drawing ___ mm
• Real vertical 60 mm → Drawing ___ mm
• Real diagonal 80 mm → Drawing ___ mm

We practise technical lettering for "SPAN", "DECK", "CHORD".

You Do · ~35 min Independent pair work

Your plan + elevation drawing (30 min).

1. Get A3 grid paper, ruler, 2H pencil, eraser.
2. Draw your title block first.
3. Draw elevation view (side view of your bridge) at 1:5.
4. Draw plan view (top view, showing both trusses + deck) at 1:5.
5. Label all major components — top chord, bottom chord, verticals, diagonals, deck, abutment.
6. Add dimension lines — every major member labelled with its real-world length (e.g. "60 mm").
7. Scan/photograph and paste into your digital folio.

Differentiation

Exit Ticket · 5 min

1. What is the difference between a plan view and an elevation view?
2. Why do we use scale in engineering drawings?
3. What is ONE rule of technical lettering?

📚 Resources for this lesson

• Term 1 L10 recap — scale & technical lettering
• Example plan + elevation drawing (on hub)

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