When something’s obsolete, it means it’s outdated and not used anymore. That’s the case with transporter bridges. They’re kind of fun, but they are not very practical. These movable bridges were used when there were lots of boats using the water and only a small number of people crossing it.

A transporter bridge is a platform hanging from a metal frame that carries cars and people. It’s pulled back and forth from shore to shore by a system of cables.

Materials:

– 2 open-backed chairs

– hole punch, tape, scissors, and roll of string

– 5″x7″ piece of cardboard

– two 5″ drinking straws

– small, shallow box lid

(from Bridges: Amazing structures to Design, Build and Test, page 76, 77 and 78)

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