Weathering and Erosion 5 th Grade

What is weathering? Physical break up of the rocks on Earth’s surface into smaller pieces of sand or rock. Physical break up of the rocks on Earth’s surface into smaller pieces of sand or rock. It is a slow occurring process that takes place over time. Most weathering takes place at the Earth’s surface. It is a slow occurring process that takes place over time. Most weathering takes place at the Earth’s surface. 2 types of weathering: mechanical & chemical. 2 types of weathering: mechanical & chemical. Mechanical weathering = breaking of larger rocks into smaller pieces of rock, called sediment. Mechanical weathering = breaking of larger rocks into smaller pieces of rock, called sediment. Chemical weathering = rocks change into other materials. Chemical weathering = rocks change into other materials.

Mechanical Changes Ice (glaciers) – when water freezes it expands. When water trickles down the cracks of rocks, it can break the rocks apart when it freezes. Ice (glaciers) – when water freezes it expands. When water trickles down the cracks of rocks, it can break the rocks apart when it freezes. Wind – smoothes and polishes rocks as it strikes the surface. Wind – smoothes and polishes rocks as it strikes the surface. Water – can break rock into very small pieces. Rocks carried down a swiftly moving river are weathered as they bump into each other. (strongest weathering process) Water – can break rock into very small pieces. Rocks carried down a swiftly moving river are weathered as they bump into each other. (strongest weathering process) Waves – crash against the shoreline, which causes the land to weather away. Waves – crash against the shoreline, which causes the land to weather away. Gravity Gravity Plants and animals can help cause weathering as well. Plants and animals can help cause weathering as well.

Chemical changes Water is the main factor that causes chemical weathering. Water is the main factor that causes chemical weathering. Water can dissolve certain minerals that make up rocks. Water can dissolve certain minerals that make up rocks.

Pictures of Weathering

Weathering

Weathering

Weathering

What causes erosion? Process of moving weathered bits of rock or dirt from one place to another. Process of moving weathered bits of rock or dirt from one place to another. 4 types: glaciers, wind, water, and gravity 4 types: glaciers, wind, water, and gravity Deposition – dropping of sand and rock carried by wind or water as it slows down or from ice that melts. Deposition – dropping of sand and rock carried by wind or water as it slows down or from ice that melts. Beaches, sandbars, deltas, and sand dunes form when disposition occurs. Beaches, sandbars, deltas, and sand dunes form when disposition occurs. Erosion is carried away by moving water, wind, and ice. Erosion is carried away by moving water, wind, and ice. Plants, trees, and shrubs help reduce erosion; therefore, if you live in the mountains it is important to plant some. Plants, trees, and shrubs help reduce erosion; therefore, if you live in the mountains it is important to plant some. Watch Bill Nye – Erosion in Earth changes folder. Watch Bill Nye – Erosion in Earth changes folder.

Glaciers Glaciers – thick layers of ice. When it slowly slides down a hill it erodes away the surface beneath it. Boulders and rocks, carried in the ice, scrape the rock beneath the glacier carving valleys into mountainsides. Glaciers – thick layers of ice. When it slowly slides down a hill it erodes away the surface beneath it. Boulders and rocks, carried in the ice, scrape the rock beneath the glacier carving valleys into mountainsides.

Water Moves the most rock on the Earth’s surface. Moves the most rock on the Earth’s surface. Rain carries the soil away as it washes over the land, leaving gullies, valleys, and canyons. Rain carries the soil away as it washes over the land, leaving gullies, valleys, and canyons. Sometimes mud and dirt can run right into houses, causing houses to be covered in dirt and mud. Sometimes mud and dirt can run right into houses, causing houses to be covered in dirt and mud. The paths of rivers have changed over the years due to erosion. The paths of rivers have changed over the years due to erosion. Over time, the river channel becomes wider and deeper. Over time, the river channel becomes wider and deeper. Carves out the canyon in a V-shaped. Carves out the canyon in a V-shaped.

Wind Wind erosion moves back the Earth’s surface. Wind erosion moves back the Earth’s surface. It is not strong enough to carry large rocks. It is not strong enough to carry large rocks.

Gravity Affects all erosional processes. Affects all erosional processes. Pulls sand grains out of the air and rocks off cliffs. Pulls sand grains out of the air and rocks off cliffs.

Grand Canyon Was created due to deposition, uplift, and erosion. Was created due to deposition, uplift, and erosion. Mostly just uplift and erosion. Mostly just uplift and erosion.

Pictures of Erosion

Erosion

Erosion

Erosion

Weathering and Erosion formations Arches – formed by a combination of erosional forces. Ice, rain, and wind continue to weather the arches in Utah’s Arches National Park. Arches – formed by a combination of erosional forces. Ice, rain, and wind continue to weather the arches in Utah’s Arches National Park. Butte – formed by running water. Isolated hill with steep, even sides, and a flat top. (disposition and uplift cause the layering of buttes) Butte – formed by running water. Isolated hill with steep, even sides, and a flat top. (disposition and uplift cause the layering of buttes) Arches, valleys, canyons, and buttes are continually changing due to the effects of weathering and erosion. Arches, valleys, canyons, and buttes are continually changing due to the effects of weathering and erosion. Watch weathering and erosion video. Watch weathering and erosion video.

Evidence In order to make conclusions about anything you must have evidence. In order to make conclusions about anything you must have evidence. You can have the actual evidence like fossils or you can use your observational skills. You can have the actual evidence like fossils or you can use your observational skills. Oldest rocks are found at the bottom of a mountain and newest rocks found at the top. Oldest rocks are found at the bottom of a mountain and newest rocks found at the top.

Extra Credit Opportunity Find examples of weathering and erosion in UT. Find examples of weathering and erosion in UT. Take pictures or find pictures on the internet. Take pictures or find pictures on the internet. Print the pictures off and be prepared to tell us which weathering and/or erosion process caused the new land formation. Print the pictures off and be prepared to tell us which weathering and/or erosion process caused the new land formation. Due: October 8, 2008 Due: October 8, 2008