For ages 9 to 12 years. Build bridges of your design -- from the 'workhorse' truss-beam bridge to the dazzling suspension bridge. Use bridge-building basics, and, along the way, discover how science and creativity come together in the creation of those weight-bearing wonders -- bridges. Choose the best bridge design for different sites. Make decisions about cost, safety, materials, and the environment. Build and innovate using available materials. Test your construction for function and load.