How to make a geodesic dome
Use straws and strong shapes to make a self-supporting dome.
This activity may be Fiddly
Use straws and strong shapes to make a self-supporting dome.
This activity may be Fiddly
What will I need?
1.
Gather your supplies using the list above. You’ll need 35 long straws at 13cm and 30 short straws at 11cm. Pick a colour for your long straws and cut them to the correct length. Use the other colour for the short straws and cut those to the correct length too.
2.
Following the diagram, stick the straws together to start building your dome.
Blue = Long straw
Red = Short straw
Green = Sticky tape
Blue = Long straw
Red = Short straw
Green = Sticky tape
3.
At first, your dome should look like this.
4.
Continue following the diagram and stick your straws together.
5.
Continue following the diagram until the top of the dome is secure.
6.
Your finished dome should look like this!
7.
See if you can use the straws to make some different 3D shapes.
- Can you make your dome bigger, or scale it down?
- What other materials could you use to improve your finished product?
- Can you make a dome using shapes different to the one in the pictures?
Some of the straws in this activity are in compression: they are being squashed, and as a result they produce a force that pushes back. It is those forces that support the weight of the dome. The other straws are in tension: they are being stretched, and as a result they produce a force that pulls back. These tension forces prevent the structure from splaying apart and collapsing.
It is this combination of tension and compression forces that makes a triangle a strong shape, and the interconnected triangles in this activity make the dome a stable, self-supporting structure.
Architects and engineers always think carefully about the combination of compression and tension forces when designing a new self-supporting structure, whether it’s a simple garden chair or a huge, complicated bridge or building. You can often work out which parts of a structure are generating which kind of force.
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