How a Centrifuge Works

Change the rpm, radius and substance densities to see how the mixture separates.

Controls

Water ≈ 1.0. Higher = thicker liquid.

Substances in the mixture

Liquid medium density is fixed at 1000 kg/m³ (water). A substance denser than this sinks outward; lighter than this floats inward.

Top-down view of the spinning rotor

Inward push from liquid + wall (= the centripetal/resultant force) Velocity (tangent) Apparent centrifugal (rotating frame)

Force budget — why the densest sinks

Playback & view

Point of view

Live readouts

Angular speed ω
Accel. at outer end
As multiple of g
Separation strength
Centripetal acceleration: a = v² / r
Centripetal force: F = m v² / r
Angular speed: ω = 2πf  (f = rpm ÷ 60)
Centrifuge acceleration: a = ω² r

Separation graph

Average radial position of each substance over time.

What is happening?

Common misconception: From outside the centrifuge there is no real outward force. The particles tend to keep moving in a straight line while the tube curves around them. The tube wall and liquid push inward, providing the centripetal force for circular motion. Only in the rotating frame do we describe an apparent centrifugal force.