Weathering is the process of breaking down rocks, soil, and minerals through contact with the Earth's atmosphere, biota, and water. There are three main types of weathering:

* Physical weathering: This involves the mechanical breakdown of rocks into smaller pieces, without changing their chemical composition. Examples include:

* Frost wedging: Water freezes in cracks in rocks, expands, and breaks them apart.

* Thermal expansion: Rocks expand and contract with changes in temperature, causing them to break.

* Abrasion: Rocks rub against each other, causing them to wear down.

* Chemical weathering: This involves the chemical alteration of rocks, changing their composition and weakening them. Examples include:

* Oxidation: Iron in rocks reacts with oxygen, creating rust and weakening the rock.

* Carbonation: Carbon dioxide in the atmosphere dissolves in water, forming carbonic acid, which can dissolve limestone.

* Hydrolysis: Water reacts with minerals in rocks, breaking them down.

* Biological weathering: This involves the breakdown of rocks by living organisms, such as plants, animals, and microorganisms. Examples include:

* Root wedging: Plant roots grow into cracks in rocks and pry them apart.

* Burrowing animals: Animals dig burrows in the ground, exposing rocks to weathering.

* Lichens: Lichens produce acids that break down rock surfaces.

Once rocks are broken down by weathering, they are more susceptible to erosion. Erosion is the process of moving weathered material from one place to another by forces such as wind, water, ice, and gravity.

So, to summarize, erosion begins with weathering, which provides the loose material that can be moved and transported by erosional forces.