Spaghetti might not be the first building material that comes to mind when you are challenged to build a bridge, but spaghetti bridge building projects demonstrate the basic concepts of bridge construction and design. Spaghetti bridges can be tested for strength, weight and flexibility. Experiment with a variety of bridge design ideas as well as different types and shapes of spaghetti or pasta.
Though many bridges are of a triangle shape with the apex centred over the top of the bridge, an inverted triangle with the apex underneath the road structure creates a sturdier frame for a spaghetti bridge. To create the two end support towers, create stackable spaghetti squares by gluing together four sections of two-inch pieces of spaghetti. Continue stacking and securing squares until you have two nine-inch towers. Glue several pieces of spaghetti together to create a flat road surface; create two more flat structures in the same way and place them aside. Glue one of the flat pieces across the top of the two support towers. To reinforce strength using an inverted triangle, flip the structure over and glue the two additional flat spaghetti sections at the joints between the support towers and the flat road surface so that their ends meet in a point. Add rubber cement to the triangle's point. Once dry, flip the bridge over. Test the strength by suspending weights with strings from the point of the inverted triangle.
Test the various properties of cooked and dry spaghetti in bridge building. First, construct a simple bridge using dry spaghetti. Any basic design will work as long as you can replicate the design in a separate model. Place weights on pennies on top of the bridge or suspend them from the bridge using strings and a small cup. Record the number of pennies or weights it takes before the bridge begins to crack or break. Next, cook a batch of pasta in a pot of boiling water until the noodles are soft. Place the spaghetti on a paper towel to dry overnight. In the morning, create the same kind of bridge using the cooked and dried spaghetti noodles. Repeat the same strength test using weights. Compare the two results to determine whether cooked or uncooked spaghetti offers more strength.
Another option for building a spaghetti bridge is to use spaghetti to create a model of an existing bridge. Research the various types of bridges in the world or study some iconic bridges such as the Brooklyn Bridge or the Golden Gate Bridge. Print out several pictures of the bridge you choose to replicate. Use spaghetti to create a scale model of your selected bridge. Consider the different types of pasta you could use to best replicate the shapes of the bridge. For example, a cable bridge might use both cooked pasta that is dried in a curved shape to create the look of tension cables. You also can drape pliable cooked spaghetti into the cable position. After you've constructed your bridge, use spray paint to colour the bridge and place the bridge on a painted backdrop of its location.