1. Weathering: This process breaks down rocks into smaller pieces, often called sediment. There are three main types of weathering:
* Physical weathering: This involves the mechanical breakdown of rocks into smaller pieces. Examples include:
* Frost wedging: Water freezes in cracks, expands, and wedges the rock apart.
* Abrasion: Rocks rub against each other, grinding them down.
* Thermal expansion and contraction: Rocks expand and contract in response to temperature changes, which can cause them to break apart.
* Chemical weathering: This involves the breakdown of rocks through chemical reactions. Examples include:
* Oxidation: Oxygen reacts with iron in rocks, causing them to rust and crumble.
* Dissolution: Water dissolves some minerals in rocks, carrying them away.
* Hydrolysis: Water reacts with minerals in rocks, forming new minerals that are weaker and more easily broken down.
* Biological weathering: This involves the breakdown of rocks by living organisms. Examples include:
* Plant roots: Plant roots grow into cracks in rocks, widening them and breaking them apart.
* Animals: Burrowing animals can break up rocks, and some animals use rocks for tools, which can also break them down.
2. Erosion: This is the process of moving weathered rock and soil from one location to another. The most common agents of erosion are:
* Water: Rain, rivers, and waves can all carry away sediment.
* Wind: Wind can pick up and transport sediment, especially in dry areas.
* Ice: Glaciers can move large amounts of rock and soil.
* Gravity: Gravity pulls sediment downhill, causing landslides and other forms of mass wasting.
These two processes, weathering and erosion, work together to constantly reshape the Earth's surface, creating landscapes like mountains, valleys, and beaches.
