Balsa Wood Bridge

I constructed this bridge out of balsa wood for a high school physics class. The mass of the finished bridge was 44.85g (1.58 oz. on earth). The bridge was tested by loading to failure at 291 lbf. As can be seen by the asymmetrically crushed wood on the deck, the load application was not perfectly centered and a higher ultimate loading was probably possible. This is a good example of how unforeseen factors can cause design loads to vary from those actually experienced, and is one reason why factors of safety are so important. The adhesive used was general purpose epoxy.