Ages 4-7 · child and adult
Arch bridge: support a roadway
Curve cardboard into an arch underneath a paper roadway. Compare the bridge with and without its support.
Set your own pace. Preparation depends on your materials.
What to gather
- Thin cardboard strip about 25 × 8 cm
- Two thick books as supports
- Paper strip about 30 × 10 cm for the road and a light toy car
- Paper tape
Keeping it safe This floor model is only for a light toy. Never stand, sit or test body weight on it.
Choose a challenge level
Ages 4-5
The adult holds the supports; the child compares the roadway before and after adding the arch.Ages 6-7
Change the support spacing and see whether the arch still supports the road. Do not add heavy loads.Step-by-step instructions
Place two books on the floor with a gap shorter than the cardboard strip. Span it with a paper roadway and gently place a light car on top.
Rest the cardboard ends on the floor against the inner book faces. Adjust the gap until the low arch just touches the underside of the paper road. Secure the books against sliding.
Place the same car in the same spot. Watch both roadway and arch ends. If the supports move, stop and secure them better.
TATAAA
Now turn it into a game
City engineers: join two cardboard neighbourhoods with the bridge. Deliver a parcel across a paper river.
When it gets tricky
Arch spreading out? It needs support at both ends. Reduce the gap and use stiffer cardboard.
When an experiment goes wrongWhen you are done
You identify the arch supports and compare the road with and without the arch.
If your child does not want to continue, it is fine to stop. You can safely swap roles or adapt the rules.
What to notice
An arch transfers some load sideways towards its supports. If they spread apart, the shape can collapse.
