Bill Robertson thinks that questioning the physics behind simple machines is a great idea because when he encounters the subject of simple machines in textbooks, activities, and classrooms, he seldom encounters, a scientific explanation of how they work. Instead, what one often sees is a discussion of load, effort, fulcrum, actual mechanical advantage, ideal mechanical advantage, and so on. Simple machines are not included in the "Next Generation Science Standards." The reason for that is that the subject in and of itself is not considered a major science principle. Simple machines are, however, a great application of major science principles, and lots of them are used in everyday life. Therefore, there's no reason not to include them in a science program as long as the students investigate the scientific principles behind them. This article begins with the simplest of simple machines, an inclined plane. It moves on to discuss levers, and it eventually introduces the principles behind the multi-speed bicycle. The main message regarding simple machines is the physics version of "There's no such thing as a free lunch." You can trade force for distance, but you can't get something for nothing.