Pressure = Force / Area. It describes how concentrated a force is over a surface.
Common Units
- 1 atm = 101,325 Pa = 14.696 psi = 1.01325 bar
- 1 bar = 100,000 Pa β 14.504 psi
- mmHg: 1 atm = 760 mmHg (used in medicine)
Types
- Atmospheric: Weight of air above a surface (14.7 psi at sea level)
- Gauge: Pressure above atmospheric (tire pressure)
- Absolute: Gauge + atmospheric (used in thermodynamics)
- Hydrostatic: P = Οgh (pressure from fluid depth)