Forces That Shape Our Earth: Weathering And Erosion
Weathering & Erosion: Erosion and weathering are major forces that shape Earth’s surface. For example, the Grand Canyon was formed through erosion by the Colorado River running through it!
What is weathering?Weathering: The breaking down of rocks into smaller pieces.1. Mechanical /Physical2. Chemical Hulk Rock Smash!
So what is erosion?Erosion: The movement of weathered rock by wind, water, glaciers & gravity
Types of Weathering:Mechanical/Physical: Rock is physically broken into smaller pieces (larger pieces become smaller pieces of the same rock)Chemical: Rock is chemically changed (like rusting or dissolving away)
5 Agents of Mechanical Weathering:1. Release of Pressure2. Freezing & Thawing3. Animal Actions4. Plant Growth5. Abrasion
Release of Pressure As the surface of a rock is eroded, the rock begins to release pressure Causes top layers of the rock to crack and flake off
Release of pressure: rock cracks like an egg shell
Freezing & ThawingWhen water in the cracks of rocks freezes it expands causing the crack to enlarge or get bigger. The ice melts & refreezes over & over, breaking the rock apart.