What is weathering?
http://education.nationalgeographic.com/education/encyclopedia/weathering/?ar_a=1
Weathering is the breaking down or dissolving of rocks and minerals on Earths surface. Water, ice, acids, salt, plants, animals, and changes in temperature are all agents of weathering.
Once the rock has been broken down, a process called erosion transports the bits of rock and minerals away. No rock on Earths surface is hard enough to resist weathering. Together, the processes of weathering and erosion carved the Grand Canyon, in the U.S. state of Arizona. This massive canyon is 446 kilometers (277 miles) long, as much as 29 kilometers (18 miles) wide, and 1.6 kilometers (1 mile) deep.
Weathering and erosion constantly change the Earth. Weathering wears away exposed surfaces over time. It smoothes sharp, rough areas on rocks. Weathering also helps create soil as tiny bits of weathered rock mix with plant and animal remains.
Weathering can be a mechanical or a chemical process. Often, these two types of weathering work together.
Weathering is the breaking down or dissolving of rocks and minerals on Earths surface. Water, ice, acids, salt, plants, animals, and changes in temperature are all agents of weathering.
Once the rock has been broken down, a process called erosion transports the bits of rock and minerals away. No rock on Earths surface is hard enough to resist weathering. Together, the processes of weathering and erosion carved the Grand Canyon, in the U.S. state of Arizona. This massive canyon is 446 kilometers (277 miles) long, as much as 29 kilometers (18 miles) wide, and 1.6 kilometers (1 mile) deep.
Weathering and erosion constantly change the Earth. Weathering wears away exposed surfaces over time. It smoothes sharp, rough areas on rocks. Weathering also helps create soil as tiny bits of weathered rock mix with plant and animal remains.
Weathering can be a mechanical or a chemical process. Often, these two types of weathering work together.
Types of Weathering
Physical Weathering
![Picture](/uploads/3/9/4/3/39434357/4534990.png?328)
Physical weathering, also known as mechanical weathering, is the process by which rocks break down through natural, physical means. You can further define physical weathering by breaking it into groups based on cause
Mechanical Weathering
Mechanical weathering, also called physical weathering, causes rocks to crumble. Water seeps into cracks and crevices in rock. If the temperature drops low enough, the water will freeze. When water freezes, it expands. The ice then works as a wedge. It slowly widens the cracks and splits the rock. When ice melts, water performs the act of erosion by carrying away the tiny rock fragments lost in the split.
Mechanical weathering also occurs as the rock heats up and cools down. The changes in temperature cause the rock to expand and contract. As this happens over and over again, the rock weakens. Over time, it crumbles.
Another type of mechanical weathering occurs when clay or other materials near hard rock absorb water. The clay swells with the water, breaking apart the surrounding rock.
Salt also works to weather rock. Saltwater sometimes gets into the cracks and pores of rock. If the saltwater evaporates, salt crystals are left behind. As the crystals grow, they put pressure on the rock, slowly breaking it apart.
Plants and animals are agents of mechanical weathering. The seed of a tree may sprout in soil that has collected in a cracked rock. As the roots grow, they widen the cracks, eventually breaking the rock into pieces. Over time, trees can break apart even large rocks. Even small plants, such as mosses, can enlarge tiny cracks as they grow.
Animals that tunnel underground, such as moles and prairie dogs, also work to break apart rock and soil. Other animals dig and trample rock aboveground, causing rock to slowly crumble.
Picture from
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252Ffile%252Fview%252Ftafoniorso.jpg%252F390960692%252F382x256%252Ftafoniorso.jpg%3Bhttp%253A%252F%25
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Mechanical Weathering
Mechanical weathering, also called physical weathering, causes rocks to crumble. Water seeps into cracks and crevices in rock. If the temperature drops low enough, the water will freeze. When water freezes, it expands. The ice then works as a wedge. It slowly widens the cracks and splits the rock. When ice melts, water performs the act of erosion by carrying away the tiny rock fragments lost in the split.
Mechanical weathering also occurs as the rock heats up and cools down. The changes in temperature cause the rock to expand and contract. As this happens over and over again, the rock weakens. Over time, it crumbles.
Another type of mechanical weathering occurs when clay or other materials near hard rock absorb water. The clay swells with the water, breaking apart the surrounding rock.
Salt also works to weather rock. Saltwater sometimes gets into the cracks and pores of rock. If the saltwater evaporates, salt crystals are left behind. As the crystals grow, they put pressure on the rock, slowly breaking it apart.
Plants and animals are agents of mechanical weathering. The seed of a tree may sprout in soil that has collected in a cracked rock. As the roots grow, they widen the cracks, eventually breaking the rock into pieces. Over time, trees can break apart even large rocks. Even small plants, such as mosses, can enlarge tiny cracks as they grow.
Animals that tunnel underground, such as moles and prairie dogs, also work to break apart rock and soil. Other animals dig and trample rock aboveground, causing rock to slowly crumble.
Picture from
https://www.google.com.bn/search?q=phsical+weathering&espv=2&biw=1366&bih=667&source=lnms&tbm=isch&sa=X&ei=sH48VLL2FYvh8AXK6oHQBQ&ved=0CAYQ_AUoAQ#facrc=_&imgdii=_&imgrc=Ak3u4BZXlSxu1M%253A%3BQuYuzDWWPqBmHM%3Bhttp%253A%252F%252Fppurdy.forsyth.wikispaces.net%
252Ffile%252Fview%252Ftafoniorso.jpg%252F390960692%252F382x256%252Ftafoniorso.jpg%3Bhttp%253A%252F%25
2Fppurdy.forsyth.wikispaces.net%252F4%252BPhysical%252BWeathering%3B382%3B256
Chemical Weathering
Chemical weathering is when a statue was covered by acid due to acid rain. . Chemical weathering takes place in almost all types of rocks. Smaller rocks are easier, because they have a greater amount of surface area. This is cause to crumble away, you can see these on building or a church. |
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Biological Weathering
![Picture](/uploads/3/9/4/3/39434357/9312198_orig.png)
Biological weathering takes place when rocks are worn away by living organisms. Trees and other plants can grow from the cracks in a rock. As the roots grow bigger they open cracks the rocks making it deeper and wider. Over time the growing tree eventually prizes the rock apart.
Picture from
https://www.google.com.bn/search?espv=2&biw=1366&bih=667&tbm=isch&oq=biolgical++weathering&gs_l=img.3...25992.31961.0.32196.13.12.1.0.0.0.151.921.8j2.10.0....0...1c.1.55.img..11.2.173.-aGWgCetKDs&q=biolgical%20weathering#facrc=_&imgdii=_&imgrc=qjL6ok-yOsYk5M%253A%3BCBZsLj5CGbZCzM%3Bhttp%253A%252F%252Fwww.geolsoc.org.uk%252Fks3%252Fwebdav%252Fsite%252FGSL%252Fshared%252Fimages%252Feducation_and_careers%252FRockCycle%252FProcesses%252FWeathering%252Fbio2.jpg%3Bhttp%253A%252F%252Fwww.geolsoc.org.uk%252Fks3%252Fgsl%252Feducation%252Fresources%252Frockcycle%252Fpage3568.html%3B239%3B329
Website to check out
http://www.geography4kids.com/files/land_weathering.html
http://www.onegeology.org/extra/kids/earthprocesses/weathering.html
http://www.onegeology.org/extra/kids/earthprocesses/weathering.html