Activity 5: Making Shapes Strong

The wooden framework holding up the roof of a building has to be a strong structure. Look at this image and notice the shapes that are used to make the roof boarding structure.



This demonstrates one of the more practical and important properties of triangles – that they are rigid.

You can show this by using Meccano or something similar.

Use four Meccano strips and join them together to make a rectangle.

Try pushing it sideways – it will move like this:

Now use another strip to put in a diagonal:



What happens now? Can you push it over?

Make a triangle with three strips.



Can you push it out of shape?

This is because of the triangle's property of rigidity which is used widely in building and engineering where strength is required.

Can you think of other places where you might have seen the triangle shape used to help make something rigid and stronger?