Illustrate the stability of the basic truss design and possible reinforcement techniques.
Materials: white beans (soaked overnight), toothpicks (round ones work best), newspaper or newsprint paper
Procedure: students will construct a regular rectangle using the beans and toothpicks. Review the characteristics of a regular rectangle with class, and then instruct them to make one, using the materials stated above. After construction of the shape, it should be tested for strength. This done by pressing on a cross member beam, to determine any give or sag in the structure. Challenge the student to improve the overall stability of their design by adding material. (Students should find that stability increases with the addition of cross members. Also instruct students to extend the truss to see how wide of a gap their designs can span.