Build a machine that distributes seeds precisely.
Build a wing that can support its own weight over a span of at least two feet. Inspired by Boeing’s Phantom Eye
Build an open circuit that completes when the water level drops below a certain level and/or goes above a certain level.
Build a crane that uses simple machines and mechanical advantage to move heavy objects.
Build a water filter that can clean dirty water.
Make a cantilever that can hold 5 marbles at least 12 inches away from its base structure.
Build a 3-D object out of tetrahedra that is as big as you are.
Build a wind powered turbine that can pump water up from the ground.
Build a honeycomb structure that is able to support a heavy textbook or more.