Making Things Strong and Light

How do we make things strong and light?

• Geometry: using smart shapes to bear heavy loads.
• Materials: choosing the right material for the job.

Strength-to-weight ratio

How can we measure to see what works best?

• We can compare different structures and materials by comparing the strength-to-weight ratio of each one to the others.
• We take the strength of the material (a force or breaking stress) and divide by its weight to get the strength to weight ratio.

Strong and Light: Image Gallery

Geometry—Buildings

This gallery of images can give you inspiration for making structures that are both strong and lightweight. For a project where you can apply these ideas, see: The Leaning Tower of Pasta.

The Hong Kong and Shanghai Bank building has triangle frames around tall rods to make sure that the rods can support the building and don't buckle. Architects often play with geometry when designing buildings. Using simple shapes helps to keep the cost and weight of material down while keeping the building safe and supported.
The Eiffel Tower achieves a large strength-to-weight ratio by utilizing a truss support structure.
A construction crane is a tall tower with a truss frame that is designed to lift and move heavy objects. The height of the structure compared with its weight is very good in comparison to how much weight it can lift.

Structural plastics

Different materials have different properties. A lot of metals, like steel, are very strong, but also very heavy. Structural hard plastics are strong and durable, can be molded in just about any shape, and are lightweight.

Ropes and cords

Even simple things like ropes and cords can exhibit enormous strength for their weights. They use the fact that the materials they are made of are very strong in tension.

Superstrong: Materials and Geometry

Carbon fiber is another material that is strong in tension. When you combine it with a honeycomb shape, which is good in compression, you get a very strong structure.

Both the materials (for example, a hollow titanium or carbon fiber frame) and the geometric triangular shape of a bicycle allow it to be very strong for its low weight.