What are some uses of a centrifuge?

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entomomania eNotes educator| Certified Educator

A centrifuge is a machine that spins its contents in order to apply a centrifugal force. It is used in laboratories to bring the contents of a container to the bottom. The concept behind the function of a centrifuge can be demonstrated by swinging a bucket of water in a full circle. With enough acceleration, the centrifugal force is great enough that the water remains in the bottom of the bucket and does not pour out, even while the bucket is upside down. 

Laboratory centrifuges are used to bring all liquids in a tube to the bottom. This is useful after mixing small volumes of liquid or before pipetting, when some of the volume is stuck to the sides of the tube in droplets. A centrifuge can also be used to separate materials by density. Denser substances will collect at the bottom with less dense substances on the top. Centrifuges can therefore be used to collect suspended solids from a liquid. The solid particles are drawn to the bottom of the tube, forming a supernatant. The liquid can then be pipetted or poured from the top. For example, when blood is spun in a centrifuge it separates into denser blood cells and less dense plasma. 

Centrifuges are also used in a variety of industries outside of the laboratory. For example, they are useful in food production for separating cream from milk, or for extracting honey from honeycomb. 

When using a centrifuge it is important to keep it balanced, with weight distributed as evenly as possible. An unbalanced centrifuge will not spin smoothly and may shake and cause damage to the machine and/or samples.