Some of the best engineers and inventors are copycats. They look at how the natural world solves complex problems and use ...

Flutter valves are handheld devices that help people with chronic obstructive pulmonary disease (COPD) clear excess mucus from their airways. They work by combining positive expiratory pressure with ...

Last month's "How It Works" story gave you the basics of the four-stroke cycle, describing the motion of the intake and exhaust valves in relation to the piston moving up and down in the cylinder.

Heart valve disease happens when one or more of your heart’s four valves don’t work properly, preventing oxygen-rich blood from moving efficiently through your heart and to your body. This forces your ...