Look at the picture and answer the following questions
(a) Name the device
(b) Where do you find this device?
(c) What is the principle of this working?
(d) When the centrifuge is in use, the mixture is taken in one test tube and water in the test tube just opposite it.Why?
(e) Why do heavier particles settle at the bottom?

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Solution

Different separation techniques are present depending on the property of the substances to be separated
In centrifugation, when the mixture of components having different density, rotated (or spun) using a centrifugal machine the denser particles are forced to move to the bottom and separated
Milk is a colloid, where the fat globules are dispersed in the medium (water)
We can separate cream from milk using the centrifugation technique
The particles which are small in size (i.e which can not separate using ordinary filter paper) separated using this process
(a) The picture mentioned here is a simple centrifuge.
A simple centrifuge (in the laboratory) has a vertical shaft carrying four or more test tube holders where the mixture is put for rotation
(b) A simple centrifuge can be seen in the laboratory which has a vertical shaft carrying four or more test tube holders where the mixture is put for rotation
(c) Centrifugation is a separation technqiue which uses the principle "density difference of the components"
When the mixture of components having different densities, rotated (or spun) using a centrifugal machine the denser particles are forced to move to the bottom and separated
The centrifugal force acts on the particles and forces particles to settle down at the bottom
(d) When the centrifuge is in use, the mixture is taken in one test tube and water in the test tube just opposite it, this is because to maintain the balance of the instrument when rotated in high speed and this is called a balancing test tube.
(e) During spinning, the contents in the test tube experience higher force and greater the gravity in the tube, and particles separate depending on density. Heavier particles will experience large centrifugal force and be forced to move to the bottom

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