Centrifugation- A Method of Separation

Centrifugation is a technique used by many industries like dairy as well as hospitals.

Dairy industry depends largely on the milk, which a colloid.

While diagnosis in hospitals depends on another colloid, blood.

In order to make maximum use of these colloids, the particles present in them require separation.

The particles present are small, so they would pass through the filter paper. Thus, filtration is not viable.

The other way to separate the particles in a colloid is by considering their size.

Based on size, the larger particles can settle down in a process called sedimentation. But this would take ages.

A technique called centrifugation can make this natural process of sedimentation faster.

It follows the same principle as sedimentation, where the denser particles settle down and lighter particles float.

In this process, a force called centrifugal force is applied on the particles.

The greater the centrifugal force experienced by the particles, higher is the rate of sedimentation.

Centrifugation is basically an outward force felt by objects moving in a curved path.

It is the same force that we feel when the car takes a sharp turn, and we want to continue in the original path. As a result we are thrown outward.

Heavier objects or particles experience a greater centrifugal force.

As a result, they flung outwards with a greater force, away from the axis of rotation.

For a sample like blood to be centrifuged it is taken in a test tube and placed on a rotor.

When the rotor spins, it ensures that a centrifugal force is applied to all the particles.

Heavier particles which experience greater force, flung out farthest from the centre of the tube, to form a layer at the bottom.

The other particles form layers above it according to their sizes.

In a similar process, skimmed milk is obtained by centrifugation.

When milk is centrifuged, the light cream floats on the surface of the heavier water component.

Clothes dry in a dryer by the same principle of centrifugation.

A dryer is a simple rotating drum like unit with holes in it.

On turning the dryer on, centrifugal force springs water particles out through the holes, thus, drying the clothes.

Revision

Centrifugation is a technique used by many industries like dairy as well as hospitals.

Centrifugation follows the same principle as sedimentation, where the denser particles settle down and lighter particles float.

It is used to separate cream from milk, to separate the components of blood. It is also used to dry clothes in a dryer.

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