Question

How will you separate a solid from a liquid by the centrifugation method?

Answer 1

Centrifugation – The process of separation of finely suspended solids from a liquid by rotating the mixture at a very high speed in an instrument called a centrifuge is called centrifugation.

For example – the separation of cream from milk.

Concept - The difference in density of components forms the basis of separation. The heavier particles settle at bottom of the container and lighter particles float above.

Process -

• Take some milk in a centrifuge tube and cover it with a cap.
• Place the tube in the holder in the centrifuge machine.
• Similarly place another sample exactly opposite to the first sample to balance the holders.
• Now set the rotation per minute(RPM) and time of rotation(in minutes) in the instrument and switch it on.
• Take the tubes out and observe the changes in them.

Observation -

• The cream and milk get separated into layers in both the samples.
• Based on the thickness of the cream layer the amount of fat(cream) is determined.

Some other examples of centrifugation-

1. Separation of blood cells from the plasma.
2. Spin drying of clothes in washing machines.