Core Concepts Part 2
Core Concepts Part 2 Our Planet, Earth 2.4 Forces on Earth’s Surface
S
Wearing Away Earth’s Surface S Weathering: a process that breaks rocks down into tiny pieces S Two Types: Chemical Weathering: rainwater or acids carried by rainwater dissolve rocks S Mechanical Weathering: moving water, ice, or sometimes wind breaks rocks into little pieces S can happen after chemical weathering has weakened rocks S
S Helps create soil S Tiny pieces of rock combine with decaying animal and plant material S Soil and pieces of rock my undergo erosion. S A process in which water, ice, or wind remove small pieces of rock S An important process because soil is required to sustain plant and animal
life, and for agriculture S
important to human settlement patterns
Shaping Landforms S Weathering and erosion have shaped many of Earth’s landforms. S Mountains and Hills S
Mountains are wide at the bottom and rise steply to a narrow peak.
S
Hills are lower than mountains and often have rounded tops.
S
Forces within the earth create mountains, forces on Earth’s surface wear them down. S The parts of mountains and hills that are left standing are the rocks that are
hardest to wear away. S Example: Millions of years ago the Appalachian Mountains were as high
as the Rocky Mountains. Rain, snow, and wind wore the Appalachians down into much lower peaks. S
Landform region: an area in which a certain type of landform is dominant
Shaping Landforms S Plateau: a large, mostly flat area that rises above the surrounding
land. S At least one side has a steep slope. S
This slope is usually a layer of rock that is hard to wear down.
Shaping Landforms S Valleys: stretches of low land between
mountains or hills S Rivers often form valleys where there are
rocks that are easy to wear away.
Rebuilding Earth’s Surface S Deposition: the process of depositing material eroded and carried by
water, ice or wind S Creates landforms such as sandy beaches and deltas S Deposition on the sea floor can create new land
S Plains: large areas of flat or gently rolling land, are often formed by
the deposition of material carried downstream by rivers
Shaping Landforms S Delta: flat plains built on the seabed where a river fans out and
deposits material over many years
S
Wearing Away Earth’s Surface S Weathering: a process that breaks rocks down into tiny pieces S Two Types: Chemical Weathering: rainwater or acids carried by rainwater dissolve rocks S Mechanical Weathering: moving water, ice, or sometimes wind breaks rocks into little pieces S can happen after chemical weathering has weakened rocks S
S Helps create soil S Tiny pieces of rock combine with decaying animal and plant material S Soil and pieces of rock my undergo erosion. S A process in which water, ice, or wind remove small pieces of rock S An important process because soil is required to sustain plant and animal
life, and for agriculture S
important to human settlement patterns
Shaping Landforms S Weathering and erosion have shaped many of Earth’s landforms. S Mountains and Hills S
Mountains are wide at the bottom and rise steply to a narrow peak.
S
Hills are lower than mountains and often have rounded tops.
S
Forces within the earth create mountains, forces on Earth’s surface wear them down. S The parts of mountains and hills that are left standing are the rocks that are
hardest to wear away. S Example: Millions of years ago the Appalachian Mountains were as high
as the Rocky Mountains. Rain, snow, and wind wore the Appalachians down into much lower peaks. S
Landform region: an area in which a certain type of landform is dominant
Shaping Landforms S Plateau: a large, mostly flat area that rises above the surrounding
land. S At least one side has a steep slope. S
This slope is usually a layer of rock that is hard to wear down.
Shaping Landforms S Valleys: stretches of low land between
mountains or hills S Rivers often form valleys where there are
rocks that are easy to wear away.
Rebuilding Earth’s Surface S Deposition: the process of depositing material eroded and carried by
water, ice or wind S Creates landforms such as sandy beaches and deltas S Deposition on the sea floor can create new land
S Plains: large areas of flat or gently rolling land, are often formed by
the deposition of material carried downstream by rivers
Shaping Landforms S Delta: flat plains built on the seabed where a river fans out and
deposits material over many years
