The dictionary defines centrifugal force as “an inertial force which tends to pull an object outward when it is in orbit or is rotating around a center” or, to put it another way, “an outward force on a body rotating about an axis.”
To better visualize this, imagine someone swinging a rope in a circular motion (Figure 1). The person swinging the rope is in the center or axis of the circle (in a centrifuge, the rotor is the axis). Attached to the end of the rope is a ball. If, for some reason, the ball becomes detached from the rope, the ball will not continue the circular path but will go straight out—which is the direction it prefers to go (Figure 2). The force that keeps the ball moving in a circular motion as long as it remains attached to the rope is known as centrifugal force, a term that was coined in 1659 by Christiaan Huygens.
