Strengthening Structures

Design & Technology · Designing & Making · ages 7-11

Name ______________________ Date ____________

A flat piece of card is just as stiff as the same card folded into ridges.
Circle one: True False
Which shape keeps its exact form when you push on its corners: a triangle or a square?
- A triangle
- A square
- They bend the same amount
What is one simple way to make a wobbly tower more stable?
- Make the tower taller
- Make the base wider
- Take away the legs
Why do cranes and bridges often have triangle shapes in their metal frames?
- Triangles hold their shape under pushes and pulls, so the frame does not bend
- Triangles look nicer than squares
- Triangles use no metal at all
Priya's straw tower has a narrow base and keeps falling over. Which two changes would help most?
- Make it taller and add straws on top
- Paint the straws a bright color
- Widen the base and add diagonal braces
Which of these makes a strip of paper stiffer, without using any extra paper?
- Cutting it in half
- Rolling it into a tube
- Folding it flat in one place
A student says the triangles in a crane's arm are just for decoration and do not hold up any weight. What is wrong with that idea?
- The triangles carry the pushes and pulls that stop the crane's arm bending or collapsing
- Cranes do not actually have triangles in them
- The student is right, they are purely decorative
Tom says a tall tower should have a narrow base to look neat, and that braces are just for decoration. What is wrong with what Tom said?
- Tom is completely right, braces are only for decoration
- Towers never need a wide base
- A narrow base makes it easier to tip over, and braces actually carry pushes and pulls to stop the frame leaning

Answer key

For grown-ups. Fold this page away before handing over the rest.

Strengthening Structures W1-mt_QnYDI3itJY-s1

False · Folding card into ridges makes it much harder to bend than a flat sheet of the same card.
A triangle · A triangle's three sides lock together, so pushing on it can't change its shape. A square can lean sideways into a slanted parallelogram.
Make the base wider · A wider base gives the tower more support underneath, so it takes more force to tip it over.
Triangles hold their shape under pushes and pulls, so the frame does not bend · Engineers use triangles because the shape cannot change without a side bending, which makes the whole frame strong.
Widen the base and add diagonal braces · A wider base and diagonal braces, which make triangles, work together to stop a tower wobbling.
Rolling it into a tube · Rolling flat paper into a tube spreads the material around a curve, which resists bending far better than a flat strip.
The triangles carry the pushes and pulls that stop the crane's arm bending or collapsing · Real engineers add triangles on purpose because the shape resists changing, letting the frame carry heavy loads without bending.
A narrow base makes it easier to tip over, and braces actually carry pushes and pulls to stop the frame leaning · A narrow base is less stable, and braces, usually forming triangles, do real work holding the frame rigid.