How Tire Pressure Gauges Work

A tire pressure gauge is a relatively simple device. See more car gadget pictures.

If you've got a car, you probably own one of those pen-sized tire-pressure gauge­s. It's got a funny little spherical thing on one end and a little sliding scale on the other end.

Have you ever wondered how it measures the pressure? And why doesn't the little scale just blow ­out the end?

In this article, we'll figure out exactly how these pressure gauges work!