Separation of Substances (Class - VI)

We use the method of filtration to separate the tea leaves from the prepared tea. The tea strainer is held in the hand while pouring the tea in the cup. The liquid tea is poured into the cup, and the tea leaves remain in the strainer. This method is called filtration. 

Copper is not a mixture, but an element. It is made of only one type of atom that is copper.

Water is not a component of crude oil. We do not get water when crude oil is refined or processed.

The harmful substances from rice like stones and insects are separated from picking by hand. The stones and insects are picked by hand and then separated from it. 

Sieving is a method of separation, which is used at construction sites. In this process, the stones or pebbles are separated from sand by sieving. Sand is needed at construction sites for construction like buildings, temples etc.

Shallow vessel with small holes at its bottom is used in sieving. A sieve is a shallow vessel with small holes at its bottom, and hence the method of separating the components of a mixture that are of different sizes is called sieving.

Kerosene oil and water can be separated by the process of decantation by using a separating funnel. Kerosene oil does not dissolve in water and forms a seperate layer. As kerosene is lighter, it would remain in the separating funnel and water being heavier would fall down in the beaker.

Sand is separated from water in sedimentation. When sand settles down at the bottom of the beaker and the clear water is left above the layer of sand, it is known as sedimentation.

Separating grains from the rest of the plant is an example of threshing, not filtration. 

Salt is separated from sea water by the process of evaporation. The sea water is a liquid. Hence, it changes into vapours and vaporizes whereas salt being a solid does not. Thus, we get salt from sea water by the process of evaporation.

The opposite of evaporation is condensation.<span style="font-family:" arial;="" font-size:="" small;=""> I<span style="font-family:" arial;="" font-size:="" small;="">n evaporation, l<span style="font-family:" arial;="" font-size:="" small;="">iquid is changed into vapours whereas the vapours are changed into liquid in condensation. In evaporation, there is heating whereas in condensation there is cooling.

In threshing, the food grains are separated from the rest of the plant. This is done in the agricultural field. As only farmer works in the agricultural field, this method of separation is used by the farmer only.

The method of sieving is used to separate coarse flour from fine flour. The sieve is a shallow vessel with small holes in it. The fine flour being heavier falls down below the sieve, and the coarse flour being lighter remains on the sieve.

The solubility of a saturated solution increases upon heating. For instance, if there is some undissolved sugar in a solution of water and sugar, and if it is heated, we find that the undissolved sugar at the bottom of the beaker dissolves. This is because the temperature increases.

Solution in which no more substance can be dissolved is called saturated solution. Some salt (substance) is left undissolved. Hence, it means that no more salts can be dissolved in water.