Gas pressure results from molecules bouncing off surfaces

Evidence

Pressure is the force, in newtons, exerted by a gas on a surface. This arises because the gas molecules “bounce” off the surface. It is measured in newtons per square meter (N m−2). — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 79

Categorization

• DEFINE: Clean physical definition of pressure grounding the sound-wave picture.