Here's why:
* Mechanical weathering is the physical breakdown of rocks into smaller pieces. Think of it like breaking a cookie into smaller crumbs. The cookie's ingredients (flour, sugar, etc.) stay the same, only the size changes.
* Chemical weathering is the process where the chemical composition of the rock is altered. This can involve reactions with water, oxygen, acids, or other substances.
Examples of Mechanical Weathering:
* Frost wedging: Water seeps into cracks, freezes and expands, putting pressure on the rock and causing it to break.
* Abrasion: Rocks rub against each other, wearing them down. This happens in rivers, glaciers, or windstorms.
* Root wedging: Plant roots grow into cracks and expand, putting pressure on the rock.
Examples of Chemical Weathering:
* Oxidation: Iron in rocks reacts with oxygen to form rust (iron oxide).
* Dissolution: Some minerals dissolve in water, especially acidic water. This is how caves form.
* Hydrolysis: Water reacts with minerals in the rock, changing their composition.
In short: Mechanical weathering breaks rocks down physically, but the chemical makeup of the rock remains the same.
