Technologies K–10 · Years 3–4

Folded paper beams: flat, channel and tube

Design and Production (NSW Science and Technology K–6, 2017); Design and Technologies: Knowledge and understanding, Technologies context: Engineering principles and systems (ACARA v9)

Practical, model not builtLow risk

This site has no interactive model of its own. Where a step or a material names a Concept Studio model, simulation or tool, it has not been built; an external simulation a step names (for example PhET) is not part of this site.

The idea

Folding or rolling the same sheet of paper moves the paper away from its middle line, which makes a beam that bends far less and carries far more load than the flat sheet.

What you need

A4 copy paper, 80 gsm, 10 sheets per group (3 trials of each of the 3 shapes, plus 1 for the fourth shape in step 5)
2 equal stacks of books with a 20 cm gap between them
1 small paper cup as the load holder
40 twenty-cent coins (11.3 g each) or 10 g slotted masses
Sticky tape and a ruler

How to do it

Lay a flat sheet across the gap with its 29.7 cm side along the span. Put the cup in the middle and add coins one at a time until the sheet folds or the cup slides off. Count the coins.
Fold 3 cm up along each long edge of a new sheet to make a channel with a 15 cm floor. Test it the same way.
Roll a new sheet along its 21 cm side into a tube 29.7 cm long, overlap the edges by 1 cm and tape the seam. Test it with the cup on top in the middle.
Repeat each test 3 times with fresh sheets and record every count.
Explain why the folded shapes hold more, then draw the cross-section of a fourth shape with labelled dimensions, predict where it will rank, make it and test it.

What you should see

The flat sheet droops under its own mass of about 5 g and gives way almost as soon as coins go in the cup; both folded shapes hold many coins. Bending stiffness depends on how far the paper sits from the middle line of the beam: for paper 0.10 mm thick, the channel is about 80,000 times and the tube about 580,000 times stiffer than the flat sheet. The coins carried rise far less than those numbers, because folded shapes fail when the paper crumples at the load point, which the stiffness calculation does not include. When the tube carries fewer coins than the channel it is because it crushed flat under the cup. The learner knows it worked when the flat sheet is last in all 3 trials and they can point to where each folded shape failed.

What changes

What you change: the shape of the sheet (flat, channel, tube)
What you measure: the number of coins carried before failure
What you keep the same: the same paper (A4, 80 gsm)
the same 20 cm span
the load at the middle
coins added one at a time

Common misconceptions

Each of these ideas is wrong, and the activity is a chance to test it.

A beam is strong because of how much material it has (the same sheet becomes stiffer only by changing shape).
The stiffest shape always carries the most load (a stiff tube can still crush at the point where the load sits).
Paper is too weak to build with (folded paper carries many times its own mass).

Safety card

Low riskLearners carry it out

Hazards

Falling books and coins

Controls

Book stacks low and stable; coins counted back in

Note

No chemicals or heat. Record the activity on Primary School RiskAssess (riskassess.com.au).

Curriculum references

The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.

Science and Technology K–6 Syllabus (2017), NESA. The syllabus taught in 2026; the 2024 syllabus replaces it from 2027. Code read from the official syllabus document (DOCX) on 2026-09-22.ST2-2DP-T ST2-9PW-ST
Science and Technology K–6 Syllabus (2024), NESA. Implementation from 2027, so this code describes the future syllabus. Code read from the outcomes page on 2026-09-22.ST2-DDT-01
Australian Curriculum v9AC9TDE4K02AC9TDE4P01AC9TDE4P02AC9TDE4P03

Sources

The pages the author read to write this activity.

All Concept Studio activities