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Rocking all over the world
Transcript of Rocking all over the world
The Earth is thought to be 4,600 million years old. Life is believed to have become dominant on earth 542 million years ago.
It is solid and made up of iron and nickel with temperatures of up to 5,500°C.
The inner core is in the centre and
is the hottest part of the Earth.
The outer core is the layer surrounding the inner core.
It is a liquid layer, also made up of iron and nickel.
It is still extremely hot, with temperatures similar to the inner core.
It is made out of four distinct layers:
The mantle is the widest section of the Earth.
It has a diameter of approximately 2,900 km.
The mantle is made up of semi-molten rock called magma. In the upper parts of the mantle the rock is hard, but lower down the rock is soft and beginning to melt.
The crust is the outer layer of the earth. It is a thin layer between 0-60 km thick.
The crust is the solid rock layer upon which we live.
At a destructive boundary the plates move towards each other, friction causes earth quakes and magma can rise through the cracks in the crust, causing a volcanic eruption.
There are two different types of crust: continental crust, which carries land, and...............
oceanic crust, this carries water.
These crusts are broken up into pieces called plates.
The point where two plates meet is called a plate boundary. This is where earthquakes and volcanoes are most likely to occur
In a constructive boundary the plates move apart and magma rises from the mantle, when it reaches the surface it cools and solidifies forming a new crust.
Eventually the new rock builds up forming a volcano.
Constructive boundaries tend to be found under the sea.
Rocks are made of grains that fit together. Each grain in the rock is made from a mineral, which is a chemical compound. The grains in a rock can be different colours, shapes and sizes.
Some types of rock have interlocking grains that fit tightly together. Granite is a rock with interlocking grains.
Other types of rock have rounded grains. Sandstone is a rock with rounded grains.
These little bits of our earth are washed downstream where they settle to the bottom of the rivers, lakes, and oceans.
For millions of years, little pieces of earth has been eroded-broken down and worn away by wind and water.
Layer after layer of eroded earth is deposited on top of eachother. These layers are pressed down more and more through time, until the bottom layers slowly turn into rock.
Igneous rocks are called fire rocks and are formed either underground or above ground. Underground, they are formed when magma, deep within the earth becomes trapped in small pockets. As these pockets of magma cool slowly underground, the magma becomes igneous rocks.
Igneous rocks are also formed when volcanoes erupt, causing the magma to rise above the earth's surface. When magma appears above the earth, it is called lava. Igneous rocks are formed as the lava cools above ground.
This is an example of sedimentary rock
Here is an example of Igneous rock
The rocks are under tons and tons of pressure, which fosters heat build-up, and this causes them to change that why the grains in the rock are so flattened.
Metamorphic rocks are rocks that have "morphed" into another kind of rock. These rocks were once igneous or sedimentary rocks.
Here is an Example of Metamorphic rocks
Biological weathering- Animals and plants can wear away rocks.
This is called biological weathering.
Weathering is when rocks Wear away or change the appearance by different processes.
There are 3 types of weathering:
When a rock gets hot it expands a little, and when a rock gets cold it contracts a little. The wind can blow tiny grains of sand against a rock. These wear the rock away and weather it.
We call this rain 'acid rain'. So when it rains,
Physical weathering is caused by physical changes such as changes in
Temperature, freezing and thawing, and the effects of wind, rain and waves.
If water gets into a crack in a rock and then freezes, it expands and pushes the crack further apart. This process of freezing and thawing can continue until the crack becomes so big that a piece of rock falls off.
Chemical weathering- When fossil fuels are burned,
For example rabbits can burrow into a crack in a rock,
making it bigger and splitting the rock.
carbon dioxide and sulphur dioxide escape into the air. These dissolve in the water in the clouds and make the rainwater more acidic than normal.
minerals in rocks may react with the rainwater, causing the rock to be weathered.
Is the movement of the broken pieces away from the site of weathering by wind, water or other natural agents.
Rivers and streams can move pieces of rock. This is called transport.
Fast flowing rivers can transport large rocks, but slow moving rivers can only transport tiny pieces of rock.
The Rock Cycle
The rock cycle is a group of changes
between the 3 types of rocks
When Earth's tectonic plates move around, they produce heat. When they collide, they build mountains and metamorphose.
Magma is a hot liquid made of melted minerals. The minerals can form crystals when they cool.
When it pours out on Earth's surface, magma is called lava, which comes out of volcanoes when it erupts
On Earth's surface, it can be weathered by wind and water and eroded.
Baked rock does not melt, but it does change. It forms crystals. If it has crystals already, it forms larger crystals. Because this rock changes, it is called metamorphic.
Igneous rock forms when magma cools and makes crystals.
Igneous rock can form underground, where the magma cools slowly, or above ground, where the magma cools quickly.
Usually, the rock pieces, called sediments, drop from the wind or water to make a layer. The layer can be buried under other layers of sediments.
After a long time the sediments can be cemented together to make sedimentary rock. In this way, igneous rock can become sedimentary rock
All rock can be heated, inside Earth there is heat from pressure.
There is heat from friction.
The heat bakes the rock.
The rock cycle continues. Mountains made of metamorphic rocks can be broken up and washed away by streams. New sediments from these mountains can make new sedimentary rock.
So it keeps on going and never stops!
Thank you for watching