Use the available wooden members to construct a bridge with cross beams. Each wooden member is inserted diagonally in the pre-drilled holes. They are then secured using the nuts and bolts provided. Once the model is completed, it is helpful to show how it works before the students begin their activity. Secure the coffee tin containing rocks witha rope onto the model. Then, one by one, remove each diagonal member to show buckling and the benefit of cross bracing. The students should remember this fact and use it when they are constructing their structure.