Grains can be separated from dirt by sedimentation and decantation. When water is added to the grains, the dust and dirt dissolve in the
water, making it muddy. Thus, the dirt and grains are separated.
The grains settle at the bottom because they are heavier.
This process of the settling of the heavier substance is called sedimentation.
Now, the grains can be separated by simply pouring out
the water. This process is called decantation.
Oil and water can also be separated by decantation and sedimentation. Water is heavier than oil, so it settles at the bottom if left alone for some
time. The oil can then simply be poured out.
The water left behind can be further cleaned using a filter paper. While water passes through the fine pores of the filter, dirt will sift out, leaving the water clean.
This process of using a filter to separate substances is called filtration.
Salt and water from salty water can be separated by evaporation.
We need to boil this water so that its temperature rises and it converts into steam.
This process is called evaporation.
The steam turns back into water when it comes in contact with a
cold metal lid. This process is called condensation.
A mixture of sand and salt can be separated by combination of methods.
The first method is sedimentation and decantation. This mixture is put in water
and left for the sand to settle for some time. Then, we will decant the salty water, which will separate the sand from the mixture.
Now the salt can be separated from the water by evaporation. The water will boil away, leaving the salt behind.
So, the mixture of the sand, salt and water has been separated successfully using a combination of sedimentation, decantation, evaporation and condensation.