In their default state — meaning no load is applied to them — extension springs are compact. The metal wire from which they are made is pressed together to form a compact coil. Extension springs, however, will become longer when exposed to a load.

The objects to which an extension spring is connected will apply a load. Extension springs are used in applications where objects pull away. You can connect an object to each end of an extension spring. And as the objects attempt to pull away, the extension spring will create its own pulling force

There are compression springs as well. While compression springs may look like extension springs, they operate in an entirely different way. Compression springs are designed to create a compressive force, meaning they become shorter when exposed to a load. In comparison, extension springs create a pulling force that makes them longer when exposed to a load.

There are different types of springs, one of the most common of which is extension. Extension springs are traditional springs that create a pulling force. They are made of a single piece of coiled metal that becomes longer when exposed to a load. As the objects to which an extension spring attempt to pull away, the extension spring will become longer while simultaneously pulling them form the ends.