Physical Means of Separating Mixtures

Sieving
In mixtures composed of differently sized particles, the big particles are separated from the finer particles using a sieve. A sieve is a utensil with fine wire-mesh bottom used for straining substances or for reducing coarse to fine particles. The process of using a sieve to separate solids with different particle sizes is called sieving.

Sieving can be distinguished from filtration in that the former is used when separating solids, while the latter is used to separate a solid from a liquid. For example, construction workers use sieves to separate gravel from sand. Bakers use sieves to remove unwanted particles from the flour used in baking bread.