Fluid Mechanics · Interactive

Hydraulic Press

Press a small piston and lift a big load — Pascal's law made tangible. Pressure spreads equally through the trapped fluid, so a gentle push on a narrow piston becomes a giant force under a wide one. You trade distance for force: the big piston rises only a sliver.

Fluid pressure P Force Connected vessel · pressure equal throughout

Setup

Small piston r₁ 4.0 cm
Large piston r₂ 16 cm
Input force F₁ 120 N
Depth probe h 0.30 m
1920 N
Output force F₂
95.5
Pressure (kPa)
1920
Output F₂ (N)
16.0×
Mech. advantage
196
Load lift (kg)
P = F₁/A₁ = F₂/A₂ F₂ = F₁·A₂/A₁ A₁d₁ = A₂d₂

Playback

Try this: make the big piston the radius of the small one → 16× the force. But watch the stroke: the big piston rises only 1/16 as far as the small one sinks. Force × distance in equals force × distance out — energy is conserved.