From TeachEngineering - In this open-ended design activity, students use everyday materials—milk cartons, water bottles, pencils, straws, candy—to build small-scale transportation devices. They incorporate the use two simple machines—a wheel and axle, and a lever—into their designs. Student pairs choose their materials and engineer solutions suitable to convey pyramid-building materials (small blocks of clay). They race their carts/trucks, measuring distance, time and weight; and then calculate