Science Experiments | Simple Machines - Introduction

Introduction

When most people envision machines, the image probably does not include a simple screwdriver or pencil sharpener. Yet these devices are also machines. A machineAny device that makes work easier by providing a mechanical advantage. is any object that makes work easier by altering the way in which the work is accomplished. Put another way, a machine can use a smaller force to overcome a larger force. In physics, workForce applied over a distance. is defined as force applied over a distance. For example, a person does work when pushing a shopping cart down an aisle, yet does no work when pushing against a closed door.

Simple machines have few moving parts, or sometimes none at all. They are the building blocks for machines of all levels of complexity and all mechanical devices. People have been using simple machines for thousands of years. Zippers, staplers, nails, and scissors are just a few examples of common modern-day machines.

Machines can enlarge and change the direction of a force, yet all machines must follow the principles of the conservation of energyThe law of physics that states that energy can be transformed from one form to another, but can be neither created nor destroyed.. This principle states that the work or amount of energy coming out of a machine is equal to the amount of energy put into the machine. Work is made up of the amount of force applied and the distance over which the force is maintained. EffortThe force applied to move a load using a simple machine. is the force applied. In mathematical terms, work equals force times distance (w=fd). Put another way, a machine that uses half the force to lift an object must then double the distance it applies the force.

Simple machines include the inclined plane, wedge, screw, lever, pulley, and wheel and axle.