Trusses are formed when two straight pieces come together to form a rigid joint. Most often they are triangular in shape and trusses are used in all types of construction from roof tops, to the Eiffel Tower and of course bridges.
The book Bridges: Amazing Structures to Design, Build & Test (Kaleidoscope Kids), explained how trusses work and then suggested a project for building a truss bridge. Again, my son jumped in.
Weighing coins to determine how much weight was applied to the bridge
A stronger ruler (road surface) was used
Free weights were used instead of coins as they were heavier
Books, weights, soup cans......... lots of heavy stuff - the bridge still held strong
Finally he got a hold of heavier weights.
The bridge reached failure.
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