Erosion is the wearing away of an object or substance through an external force. Typically, erosion refers to the gradual wearing away of soil, dirt, rock, or other land structures over time through natural forces such as water or wind.
Some of the most famous examples of erosion include the Grand Canyon, which was worn away over the course of tens of millions of years by the Colorado River with the help of winds whipping through the formed canyon; the Rocky Mountains in Colorado have also been the subject of intense geological study, with some scientists theorizing the wind and melting and freezing of glaciers has contributed to the near-complete erosion of the mountains twice already in the planet's history (the reformation of the mountain range is believed to have taken place due to shifting tectonic plates).
Humans have actually contributed to erosion in negative ways, speeding up the naturally gradual process. Some instances include deforestation, in which trees are cleared to make room for development, only to have the soil eroded by wind and water once the trees and their roots are removed.
Caves are carved out over thousands of years by flowing water, but that activity can be sped up by carbonic acid present in the water. As fresh water leeches through the rock and soil and drips through cracks, it gathers calcium carbide from the rock. When this water moves through a rock, the resulting carbonic acid erodes the rock until over time, a cave formation occurs.
2. River Banks
The banks of creeks and rivers erode over time as the water moves past it, carrying away sediment and depositing it elsewhere. The Colorado River, which flows through the Grand Canyon, drops as much as an estimated 100,000 cubic yards of sediment in Lake Powell each year. This type of soil erosion often comes as a result of water moving past the banks or walls of a river bed. Also, rocks in the river itself can be worn down and smoothed due to the constant rolling or "tumbling" motion the moving water causes.
3. Cracks in Rocks
Through a process known as exfoliation, rocks can erode due to nothing more powerful than energy from the sun. When rocks are heated quickly by the sun, the rock expands quickly. This rapid expansion can cause small cracks to form, cracks which make the rock vulnerable to wind and water erosion.
4. Gravitation Erosion
Erosion can occur from nothing more than the force of the Earth's gravity pulling on a section of rock, dirt, or land on a steep grade like a mountain, cliff, or hillside. Over time, the soil or rock becomes loose and slides downward due to the gravitation pull.
5. Coastal Erosion
The impact of waves hitting the shoreline can cause erosion of the coasts, especially during hurricanes or storm. Water can also get into cracks in the rock when a wave hits it, and that water will expand as it gets cold, causing the rock to break and be washed away. Smooth rocks and sea glass can also be formed by this "tumbling" effect of the waves.
Wind Erosion Examples
Weathering vs. Erosion
Ice Erosion Examples
Chemical Erosion Examples
Weathering and Erosion Reading Comprehension
Weathering Matching Game
Physical Weathering Examples
Science Examples for Kids