After studying the basic structure of a tower, break students into groups and have each group build a tower out of drinking straws and masking tape. Ask the students to build the tallest possible towers that can support weight, but don't let them test the strength until they have completed their towers. Stack books to see how many each tower can support. Based on what they learn, have them try again to see if they can improve the design.
Repeat the Tall Towers assignment, but this time set limitations and emphasize strength and structure. Tell students that all towers must have a minimum height and support a minimum weight and allow them to experiment and test as they go. Encourage them to create columns and triangles for support. You could compare the results against those of the first assignment to emphasize the importance of structure.
Truss bridges use the strength of triangles to support weight. Have the students research truss, deck truss and warren truss designs, and then break up the students into groups to build examples of each. Set identical dimensional requirements for each and restrict the amount of tape they may use to hold the structures together. Then lay each bridge between two desks and test the strength of each bridge using standard weight increments.
Using drinking straws and paper clips, students can create various examples of three-dimensional polyhedrons. They can start with simple tetrahedrons and cubes and then create more complex structures like octahedrons and dodecahedrons to help them visualize geometry and mathematical equations. Structures can be made by bending paper clips into V and L shapes and inserting the ends into the straws to form angled structures.