10.) A sturdy wooden ruler, piece of foam board, or thin piece of wood (we used a 24” piece of basswood, which can be purchased at a craft store) A large binder clip. Weights or variety of objects (or small paper cups and pennies to use as weights) 11.) any of the basic mechanical devices for applying a force, such as an inclined plane, wedge, or lever. 12.) Screw. Wheel and axle. Lever. Pulley.
