What it shows
A flat sheet of paper is weak, but when it is folded into a tube, a fan or a triangle it can carry heavy books. You test different shapes of paper to see which holds the most.
The science
A flat sheet bends easily because the load has nothing to resist it. Rolling paper into a tube or folding it into a zigzag spreads the load through the whole shape and stops it from buckling. Round tubes and triangles are strong because they share the push equally all around.
Materials
Cost: free. Many items come from home or from waste; spare parts such as LEDs, motors and wire are in the store.
- 10 sheets of A4 paper
- Sticky tape
- Six or more small books of equal weight
- A table
- A ruler
- Notebook
- Scissors
Safety
For this project: Keep fingers clear when stacking books and place books slowly so they do not fall on feet. An adult must help with the scissors if needed.
Never use mains electricity: power models with cells, batteries or a low-voltage adapter. Sharp and hot tools, flames and lab chemicals need an adult or your teacher beside you. Keep magnets, button cells and small parts away from young children, and wash your hands after making.
All the safety rulesStep by step
7 steps. Do them in order, and test each part before you go on to the next. Write what you notice in a notebook as you go.
Make four supports from paper: a flat sheet standing on its edge, a round tube, a square tube and a triangular tube, each 10 cm tall.
Tape each shape closed along the edge.
Place the first support on the table and set a flat cardboard on top.
Add books one at a time and count how many the support carries before it collapses.
Repeat for each shape and write the numbers in a table.
Make a zigzag folded sheet with 8 folds and test it as a bridge between two stacks of books.
Compare all results in a bar chart and say which shape is strongest.
What you should see
The round tube usually carries the most books, the triangular and square tubes come next and the flat sheet collapses at once. The zigzag bridge carries far more than the flat sheet.
Viva questions
A teacher or a judge will ask how it works. Try to answer each question before you open it, then compare.
1Why is a tube stronger than a flat sheet?
The load is spread around the whole shape.
2What is buckling?
Sideways bending of a thin object under a push.
3Why is the triangle useful in bridges?
It does not change shape under load.
4Where do you see folded paper strength?
In cardboard boxes with ridges.
Take it further
Make tubes with different widths and see how diameter changes strength.
Change one thing, measure what happens, and add a table or chart of your readings: that is what turns a model into your own investigation.
Free ebooks for this project
Science projects
Easy Science Projects for Class 1 to 5
Simple, safe projects young children can make with a little help
Science projects
Physics Working Models Explained
Twenty classic models, how each works and how to make it