Centrifuge

Definition

A centrifuge is a device that uses rotational motion to apply a force perpendicular to the axis of spin, often for separating substances of different densities. It operates by generating centripetal force to push materials outward toward the perimeter.

5 Must Know Facts For Your Next Test

1. Centrifuges operate based on centripetal force, which is required for an object to move in a circular path.
2. The magnitude of the centripetal force depends on the mass of the object, its velocity, and the radius of the circular path: $F_c = \frac{mv^2}{r}$.
3. In a centrifuge, denser substances move outward more quickly due to higher inertia relative to less dense substances.
4. The rotational speed (measured in revolutions per minute or RPM) directly affects the effectiveness of separation in a centrifuge.
5. In practical applications, such as medical labs, centrifuges separate blood components or purify samples by utilizing differences in density.

Review Questions

• What role does centripetal force play in the operation of a centrifuge?
• How does changing the rotational speed (RPM) affect the separation process in a centrifuge?
• Explain why denser substances are pushed outward faster in a centrifuge.

Related terms

Centripetal Force:

The inward force required for an object to follow a circular path, calculated as $F_c = \frac{mv^2}{r}$.

Inertia:

The resistance of any physical object to any change in its velocity; it includes resistance to changes in speed or direction.

Rotational Motion: Movement of an object around a center or axis where all points in the body follow circular paths.