Look around the place where you live. Can you find structures that contain arches, triangles, or rectangles? How does each of these shapes contribute to the success of the structure? Why would another shape be less successful? Using sketches, describe where tension and compression forces are located in each of the three shapes. How could you strengthen a rectangle with only string or rope? How could you strengthen a rectangle if you needed to leave the center open, so that you couldn't put a brace all the way across as the interactive activity did? How do triangles fail when they break?
