Key Stage 1 design and technology · Technical knowledge

KS1 design and technology: building strong, stable structures

A structure is anything that holds its shape and carries a load, from a tower of bricks to a chair or a bridge. In Years 1 and 2, children are taught to build structures and to explore how they can be made stronger, stiffer and more stable. They learn by building, testing and changing their designs using everyday construction materials such as paper, card, tubes and building bricks.

Strong, stiff, stable structures, explained

Three words matter here, and they mean different things. A strong structure does not break or collapse when something heavy is put on it. A stiff structure does not bend or wobble much. A stable structure does not fall over or tip when it is knocked or loaded. A tall tower of thin paper might stand up on a table but bend when you press the top, so it is not stiff, and a thick pole might be strong but not stable if its base is tiny. Children are not expected to give scientific definitions, but they should be able to use the words correctly.

The best way to learn is by testing. A flat sheet of paper cannot stand up on its own, but the same sheet rolled into a tube can stand on its end and hold up a small toy, and a sheet folded into a concertina can bridge a gap that a flat sheet sags across. Children discover that changing the shape of a material can make it much stiffer without adding any extra paper. Many teachers also introduce triangles, because a frame with triangular sections is harder to push out of shape than one made of squares. Schools choose how far to take this at Key Stage 1, so you may see only the tube and the fold.

Stability is about the base. A wide, flat base is more stable than a narrow one, and heavier parts kept low down make a structure harder to tip over. Children test this with towers of different shapes, and might notice that a pyramid is harder to topple than a tall thin tower. Joining matters too: a weak join is often where a structure fails, so children try tape, glue and other fixings and see which hold.

Structures are all around children, so teachers link the work to real examples such as a chair, a shelf, a garden shed, a tent or a bridge. The programme of study asks pupils to use a wide range of construction materials according to their characteristics, so children choose materials that suit the structure. In Key Stage 2, this leads on to strengthening, stiffening and reinforcing more complex structures.

Words your child will hear

Structure: Something built that holds its shape and can support a load.
Strong: Able to hold a weight without breaking.
Stiff: Does not bend or wobble easily.
Stable: Does not fall over or tip easily.
Base: The part of a structure that sits on the ground or table.
Load: The weight a structure has to carry.
Join: A place where two pieces are fixed together.

What the National Curriculum says

The programme of study for Key Stage 1 says:

When designing and making, pupils should be taught to build structures, exploring how they can be made stronger, stiffer and more stable
When designing and making, pupils should be taught to select from and use a wide range of materials and components, including construction materials, textiles and ingredients, according to their characteristics

Objectives from the National Curriculum in England, © Crown copyright, used under the Open Government Licence v3.0.

Try it: building a paper tower that holds a toy

A child is asked to build a tower from newspaper and tape, about as tall as a ruler, that can hold a small toy at the top. How do they make it strong, stiff and stable?

Test the material first. A flat sheet of newspaper cannot stand up. Roll it tightly into a tube and tape it along the edge, then stand it on end. It stands and holds a light toy without bending.
Make four tubes the same length, about as long as a ruler, and tape them so they will not unroll.
Build the tower with a wide base. Stand the four tubes in a square, tape them together at the bottom and the top, and tape a square of card across the top as a platform. A single tube with a toy on top tips over easily, but four tubes in a square give a much wider base.
Add stiffness. Tape tubes diagonally between the legs to make triangles, so that the tower does not wobble when you press on it.
Test and improve. Put the toy on top. If the tower leans or tips, spread the legs wider at the bottom or tape a piece of card across the base. Change one thing and test again.

A rolled tube is strong and stiff, a wide base makes the tower stable, and diagonal tubes stop it wobbling. A good answer names which change helped with which problem, for example “It stopped leaning when I made the base wider.”

Common mistakes and how to help

Thinking taller always means better

Children enjoy the challenge of height, so they keep adding layers. But a tall, narrow tower is less stable than a short, wide one.

What helps: Compare two towers made from the same amount of material, one tall and thin and one shorter and wider. Gently push each and see which falls first.

Mixing up strong, stiff and stable

In everyday speech the words overlap. “It’s strong” can mean anything from “it won’t fall” to “it won’t bend”.

What helps: Use a test for each. Does it break under a weight (strong)? Does it bend (stiff)? Does it tip when pushed (stable)? Asking the question makes the difference clear.

Believing more tape makes a structure better

A wrapped-up join feels firmer. But a bulky mess of tape adds little, while a well-placed tube or triangle adds a lot.

What helps: Compare a tower with lots of tape and a tower with a better shape. Ask which holds the weight and which uses less material.

Thinking flat materials cannot be strong

Paper looks weak, and children assume it can only be used flat.

What helps: Show how a rolled or folded sheet changes. Fold one sheet into a concertina and bridge a gap between two books, then place a small toy on it.

How to help at home

Stand up a tube. Roll a sheet of paper into a tube, tape it and stand it on end. Balance a paper plate on top and add small toys one at a time until it bends. Then try a fatter or thinner tube and ask your child which held more, and why they think so.
Tower challenge. Set a target such as building the tallest tower that stays up for ten seconds from cups, boxes or building bricks. Try a narrow base, then a wide one.
Spot the structures. Look for chairs, shelves, bridges and fences, and ask what keeps them from falling or bending. Notice wide bases, legs and triangular braces.
Bridge across a gap. Leave a gap between two books and ask your child to make a bridge from paper or card that holds a small toy car. Change the shape rather than adding more paper.

Leads on to

Key Stage 2: Strengthening and reinforcing structures
Key Stage 2: Gears and pulleys
Key Stage 2: Cams, levers and linkages
Key Stage 2: Series circuits in products
Key Stage 2: Programming and controlling products