Decantation is a very quick method for separating a mixture of a liquid and a heavier solid.
If we want to separate a mixture of water and same, First, we should allow the sand to settle on the bottom of the container. Then we poured off the water at the top.
The advantage of this method is quick, but there is a disadvantage of this method which is rough. It cannot be used to separate a mixture of a liquid and a light sold, such as chalk in water. The particles of chalk are suspended in the water. They are so light that they do not sink down to the bottom for a long time.