Filtration

Let us know some facts about tea.

There are tea leaves left in tea when it is prepared. Some of the leaves are floating on the surface of the tea.

For drinking purpose, tea leaves need to be removed from the tea.

Since tea is a liquid, it cannot be separated by a dry method of separation. So, a wet method of separation is used.

Let us now take a look at Filtration

Tea is poured into a strainer and it is seen that all the tea leaves are separated from tea.

All the tea leaves whether floating on the surface or settled down in water are removed.

Separation of two substances by using a barrier which allows one substance to pass meanwhile stops the other substance is known as filtration.

So, filtration is a better method of separation of substances.

The barrier has small pores on it so it allows only the liquid to pass.

The barrier has small pores and so it does not allow solid particles with size greater than pores to pass through.

The barrier is known as a filter.

The filter paper is a filter with very small pores.

A filter paper folded in the form of a cone is fixed onto a funnel.

The mixture is then poured on the filter paper. Solid particles in the mixture do not pass through it and remain on the filter.

Let us see some examples of filtration

Fruit and vegetable juices are usually filtered before drinking to separate the seeds and solid particles of pulp.

The method of filtration is also used in the process of preparing paneer in our homes.

For making paneer, a few drops of lemon juice are added to milk as it boils. This gives a mixture of particles of solid paneer and a liquid.

The paneer is then separated by filtering the mixture through a fine cloth or a strainer.

The process of filtration is used to purify muddy water from rivers.

The process of filtration is used to remove tea leaves from tea.

Revision

In wet method of separation substances can be separated in liquid or aqueous state.

There are various types of wet methods like sedimentation and decantation, filtration and evaporation, etc.

Filtration is a better method of separation of substances.

The filter paper is a filter with very small pores.

The End