The Earth’s surface changes over time as a result of natural and human activity. Some things are taken away or damaged. Other things are formed or created.
Natural ProcessesNatural processes are happening every day. Over time these processes can cause changes to the Earth’s surface such as erosion and weathering. Some changes are sudden like those caused by volcanic eruptions or earth quakes.
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Human ActivitiesMany activities that we do daily have an effect on the environment. These effects can be positive or negative on the Earth’s surface. Some of these activities can also cause natural processes to change or worsen and have a greater effect on the Earth’s surface.
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Plate Tectonics
Underneath the surface of the Earth is the lithosphere. This is humongous chunks of land called plates that can be larger than whole continents or as small as half of Australia.
These plates can move against each other and this slowly changes the location of the continents over millions of years.
The continents used to be all joint together and slowly, due to the movement of the plates, they drifted apart.
Where two plates are being pushed up against each other one may move under the other and this can create mountains and volcanoes.
Where the boundaries are being pushed apart, new land can be formed because of the magma that is pushed up and out.
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Volcanoes
Underneath the Earth’s surface is hot, liquid magma. Volcanoes are openings on the Earth’s surface that go deep down into it.
When a volcano becomes active it starts to erupt with magma coming to the surface and becoming lava and ash.
The lava can flow down the volcano and can carve out areas as it goes. When it eventually cools it can form new land structures.
When a volcano becomes active it starts to erupt with magma coming to the surface and becoming lava and ash.
The lava can flow down the volcano and can carve out areas as it goes. When it eventually cools it can form new land structures.
Natural Processes
GLACIERS |
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Glaciers are large masses that have been formed over time when falling snow turns to ice and compresses together. Glaciers move very slowly as new snow pushes the old snow down mountains.
They can dam up water and create lakes as well as hit other surfaces and cause damage or sculpt out land under them by erosion.
They can dam up water and create lakes as well as hit other surfaces and cause damage or sculpt out land under them by erosion.
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WIND |
Winds can be cold and fast. They can cause erosion of different rock and sand formations as they pick up and carry small pieces of rock or sand which slam and scrape against other surfaces.
WEATHERING |
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Weathering is when rocks, soil, minerals or materials come into contact with the atmosphere then water, natural chemicals and organisms slowly break them down.
The temperature of the atmosphere can also change the surface of Earth. Rocks expand as they get hot and if they change temperature many times cracks can form.
The temperature of the atmosphere can also change the surface of Earth. Rocks expand as they get hot and if they change temperature many times cracks can form.
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RAINFALL |
When rain falls through the sky it can dissolve chemicals from the atmosphere. When this hits the ground it can cause a chemical reaction that weakens the surface. The weight of rain can also change the surfaces especially those of sand.
As the rain continues fall it starts to form a runoff that can move loose soil and rock to new locations. In colder areas this rain can form ice that falls into cracks. As this water freezes it forces the crack apart further.
As the rain continues fall it starts to form a runoff that can move loose soil and rock to new locations. In colder areas this rain can form ice that falls into cracks. As this water freezes it forces the crack apart further.
Photo used under Creative Commons from Stabbur's Master
