Robert Gardner 
Simple Machine Experiments Using Seesaws, Wheels, Pulleys, and More [PDF ebook] 
One Hour or Less Science Experiments

Do your readers wait until the last minute to start their science project? Don’t worry, award-winning author Robert Gardner has everyone covered. Each experiment in this book follows the scientific method, and can be completed in an hour or less. Readers explore using levers to control motion and lift, and how the steepness of inclined planes affects the force needed to move something. Most experiments also include ideas for science fair projects, in case readers have more time than they originally thought.