Mathematical Bridge, Cambridge

Teach Through Educational Travel: Mathematical Bridge, Cambridge

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If you’re ever in Cambridge, England, you’ll probably visit Queens’ College. And if you visit Queens’ College, you’ll probably want to cross the River Cam via the Mathematical Bridge. It’s a unique wooden bridge, designed by carpenter and designer William Etheridge and built in 1749 by James Essex. It has been rebuilt several times (in 1886 and 1905), because it is made out of wood.

Here’s the cool part – it appears to be an arched bridge – but it is completely composed from straight boards! It is a geometric wonder, in that it uses tangent and radial trussing for its composition. This tangent and radial trussing design has been used to build other bridges, most notably Westminster Bridge (to support the bridge and allow traffic through, while the stone bridge was being built).

Teach Through Educational Travel



  • Watch this video interview with an expert, about the Cambridge Mathematical Bridge. Look at this old photo of the original 1749 bridge, and how it was decaying. And this old photo is the earliest photo of the University of Cambridge – of course, of this amazing bridge. What does this tell you about brilliant designs – and how long they last?
  • Look at this photo of the mathematical design of the bridge. See how the colors show how the straight pieces of wood are used within the structure of the bridge? If you have legos, knex, tinker toys, or an erector set, see if you can build a bridge that utilizes the tangent and radial design concepts.
  • Check out the prices that were paid for the design and construction of the bridge. The first number is pounds, the second number is shillings, and the third number is pence (or penny). Back then, one pound was divided into 20 shillings. Each shilling was divided into 12 pence. So one pound equaled 240 pence. Add up the costs of building the bridge – what were they? What does that tell you about the costs of living in the 1700s?



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