The tendency for currents of air or water to separate sediments by size is called sorting.

Here's a breakdown:

* Sorting refers to the degree of uniformity in grain size within a sediment sample.

* Well-sorted sediments have grains of similar size, indicating that they were deposited by a current with a consistent energy level.

* Poorly-sorted sediments have a wide range of grain sizes, suggesting deposition by currents with varying energy levels.

Here's how sorting works:

* Stronger currents: Carry larger, heavier sediments further.

* Weaker currents: Deposit smaller, lighter sediments first.

This process leads to the separation of sediments by size, with the larger particles settling in areas of higher energy and the smaller particles settling in areas of lower energy.