Paper Bridge Challenge

John Kerr and Sally came to visit us to talk about what an engineer does.  This was to help us to learn more about bridges.  John told us there are lots of different sorts of engineers.  John is an aircraft engineer.  A civil engineer helps build bridges.  A civil engineer decides how to build things that don't move, like bridges.
John challenged us to make a bridge from only one piece of paper using staples or cellotape.  Once we had finished our paper bridge we went to test it.  They tested it by hanging a bag off it and filling it with water bottles.  We recorded how many water bottles each bridge held.  The bridges spanned across two tables.  Joshua and Ezekiel's bridge held four bottles.
Then John brought out a bridge he had made and tested it.  It held all of the bottles except the large juice bottle.

Here is John's bridge.  It is a beam bridge with a supporting triangle truss.

Here he is placing the bottles in.  He used a pen to balance the bag off the bridge.