when a big rock breaks down what is the process called
Weathering and erosion. Weathering is the process where rock is dissolved, worn away or broken down into smaller and smaller pieces. There are mechanical, chemical and organic weathering processes. Organic weathering happens when plants break up rocks with their growing roots or plant acids help dissolve rock.
Lesson Summary [edit]. 1  Mechanical weathering breaks existing rock into smaller pieces without changing the composition of the rock. 2  Ice wedging and abrasion are two important processes of mechanical weathering. 3  The main agents of mechanical weathering are moving water, wind, glacial ice and gravity.