The class started off with a brief 'get-to-know-you' game, and then dove into the day's topic of tension and compression -- as exemplified through truss design. Jenna showed the workshop the difference between tension and compression using a block of foam with a grid laid out on it.
Then the students started modeling truss designs with the applet available at http://jhu.edu/~virtlab/bridge/bridge.html. They followed the challenge materials to design their own trusses to support a 100 weight and a 20 weight pulling sideways.
Finally, they finished off their session by constructing physical truss-based structures to support weighted cups.