Pressure (Physics)

Pressure is the Force exerted perpendicular to a surface, divided by the area over which that force is distributed. It answers a fundamental question: when you push on something, does it matter how concentrated your push is?

A sharp knife cuts better than a dull one—same Force, smaller area, greater pressure. This principle, formalized by Newton and refined through centuries of Physics, governs everything from atmospheric behavior to how hydraulic systems multiply force.

Pressure appears everywhere. The atmosphere presses down on us with about 101 kilopascals at sea level, a weight we never notice because it pushes equally in all directions. Deep underwater, pressure increases with depth, crushing most creatures that venture too far down. Inside stars and during the Big Bang, pressure becomes a cosmic architect, resisting gravity itself and determining whether a star becomes a White Dwarf or something stranger.

Engineers measure pressure in pascals, atmospheres, bars, and pounds per square inch—each unit a different language for the same physical conversation. Understanding pressure is essential for designing everything from airplane wings to submarine hulls.

Related

Density, Buoyancy, Thermodynamics, Fluid Mechanics, General Relativity