Simple machines can change the magnitude or direction of a force. Specifically, simple machines are devices that use mechanical leverage to multiply force. They are used in order to maximize the output force to perform certain tasks more efficiently and more easily. The ratio between the input and the output force is known as the mechanical advantage, and it is this advantage that determines the effectiveness of a simple machine.
There are six known simple machines. They are the lever, the wheel and axle, the pulley, the inclined plane, the wedge, and the screw. They are the elementary building blocks that are combined to form more complicated machines. For example, the mechanism of a bicycle includes a pulley, levers, and wheels.
Simple machines can be divided into two categories. The machines in the first category, which are the wheel, the lever, and the pulley, depend on torques equilibrium to perform work. In the second category, machines such as the wedge, the screw, and the inclined plane rely on the vector resolution of force.
- ThinkQuest—Simple Machines: A page that links to demonstrations of all the simple machines, along with pictures and animations.
- Simple Machines: An article from The Franklin Institute that provides detailed information about all the simple machines. It also links to extra pages for children, with diagrams for each simple machine.
- Simple Machines Learning Site: A page that links to information about each of the simple machines. It includes illustrations and a quiz.
- Mikids.com—Simple Machines: A page that gives information on each type of simple machine, and examples of tools that apply the principles of simple machines.
- Simple Machines Web Quest: A page that links to information about simple machines and how they can be combined to create more sophisticated machines. One of the links provides a list of experiments that demonstrate what simple machines are and how they work.
- Understanding Simple Machines: An article that explains how each simple machine works.
- Simple Machines (Starting With Science): A children's book on simple machines, available on Amazon.com.
- AllBookstores.com—Simple Machines: An extensive list of books on simple machines and their applications.
- Simple Machines—the Book: A Professor Breaker’s book on simple machines, written for children in first through third grade. It includes directions for many basic scientific experiments.
- Library Thing—books on simple machines: A list of useful books on various topics related to simple machines.
- Books for Teaching Simple Machines: An article which provides a list of recommended books for teachers covering simple machines. The books' subject matter ranges from basic applications to more sophisticated combinations.
- Simple Machine Science Project: Science projects that show the principles behind simple machines.
- Edheads—Simple Machines: A page that provides interactive educational activities to help children understand the principles behind simple machines. It includes a teacher's guide.
- Simple Machines: A list of links to sites that contain information about simple machines and their applications. The list is provided by Kennesaw State University.
- The Topic: Simple Machines: A site that provides all sorts of information about simple machines. It also includes links to other websites.
Nearly every modern machine depends on a combination of many simple machines to function. Nevertheless, modern industrial machines are very sophisticated and expensive, and many companies utilize equipment leasing in order to finance them. An equipment lease provides a firm with a cost effective method to acquire the machines it needs to perform certain tasks, and it is much easier for the company to afford than purchasing equipment out of working capital. People tend to overlook simple machines, but they actually play a very important role in the technological as well as economical advancement of society.