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Science Unit 2: The Earth - Coggle Diagram
Science Unit 2: The Earth
What is the Earth made out of? (Types of rocks)
Sedimentary rocks
Generally formed by the compaction and cementation of sediments
Crystalline
Precipitites
Formed by chemical reactions
Evaporites
Clastic
Compacted sediments
Classified by size
Organic
Biological matter
Bioclastic
Formed by compacted organic material (fossils/shells etc.)
The only type of rock to contain fossils and animal remains
The process that produces other types of rocks would destroy all animal reamins and fossils within them.
Igneous rocks
Classified by where they are cooled and solidified
Intrusive
Forms inside of the Earth
Magma cools slowly
Large crystals form
Extrusive
Found outside of the Earth
Lava cools quickly
Small or no crystals form
May be vesicular
Cointains air bubbles
Formed by the cooling and solidification of magma or lava
Metamorphic rocks
There are 2 types of metamorphism
Contact
Is caused when rocks are in contact with heat
Regional
Is caused when rocks face a lot of pressure
Rocks that are changed due to intense heat/pressure
Layers of the Earth
Crust
The outer layer of the earth consisting of solid rock
Mantle
The mantle is a layer of molten rock beneath the crust
Between the mantle and the crust is the asthenosphere
The asthenosphere is the layer of the mantle, which behaves like liquid
Outer core
A layer of molten iron and nickel that surrounds the core
Inner core
The core is the central part of the Earth,consisting mainly of iron and nickel
Also where gravity comes from
How the continents move (Continental drift)
Caused by the convection currents in the asthensophere the move the textonic plates around
The movement of the tectonic plates
Tectonic plates
Large slab of rock that are floating above the mantle
Makes up all of the land on the Earth
3 different types of plate movement
Convergent
Plates moving towards each other
Divergent
Plates moving away from each other
Transform
Plates sliding against each other
Volcanoes
Opening in the earth's surface where molten rock can escape
Often located at the fault lines or boundaries
Mostly found near divergent and convergent tectonic boundaries
Lava/Magma
Molten rock in the Earth’s crust is called magma
Molten rock on the Earth’s surface is called lava
Volcanoes at divergent tectonic boundaries
Magma rises up as the plate boundaries move apart to fill the gap
The magma does not reach the high pressures and has a chemical constituency that allows it to flow
The lava that flows out flows gently out of the volcano
Volcanoes at convergent tectonic boundaries
The subducted rock is melted as it reaches the mantle which releases water and gases from the rock
This process can cause the magma to have a much higher pressure
Erupts by exploding and creates pyroclastic flow
Types of volcanoes
Shield volcanoes
Shield volcanoes are large, broad volcanoes where lava pours out in thin layers, allowing it to travel farther down the shallow slopes of the volcano
Shield volcanoes build up slowly with hundreds of eruptions creating several layers
Stratovolcanoes / Composite volcanoes
Stratovolcanoes / Composite volcanoes contain a conduit system that channels magma to the surface
These volcanoes can have clusters of vents along the sides of the mountain where lava flows out
Cinder cone volcanoes
Cinder cone volcanoes occur when lava is ejected from a volcanic vent
Over time, this creates a circular or oval-shaped cone, with a crater at the top
Lava is shot into the air, and pieces accumulate around the vent
Lava dome volcanoes
Lava domes are created when small masses of thick lava that can't flow far from the source, so domes pile up around the vent
The dome grows by expansion of lava from within, and the mountain forms from material spilling off the sides of the dome
Categorizing volcanoes
Active
These are volcanoes that are currently erupting or have regular earthquakes
These are not stable
Dormant
Extinct
These are volcanoes that haven’t erupted for millions of years and are thought to be inactive and incapable of erupting again
Earthquakes
The shaking of the surface caused by movements in the crust
Normally occur at places where tectonic plates meet
A fault line is where the two blocks of rock start to break or deform the land
The release of energy underground creates seismic waves which causes earthquakes to happen
Systems used to protect buildings from earthquakes
Base isolation system
Flexible poles/bearings(base isolators) support the building from underground
When an earthquake occurs, the base isolators sway under the pressure created by the earthquake and absorb most of the movement
Pendulum system/tuned mass dampers
When an earthquake occurs, the pendulum will sway the opposite direction of the building countering the movement the earthquake creates
Huge metal balls/weights are placed in the building suspended by wires
Metal weights also absorb vibrations caused by earthquakes, dampening its impact.
Shear walls
Designed to resist shaking and movement
Made of wood, concrete, gravel and rubber which absorb the waves
Cross bracing
Made out of metal wires/beams arranged in an “X” shape
Reduces the chance of the building collapsing
Supports the building from wind
Reduces the amount of shaking and swaying during an earthquake
The atmosphere
The greenhouse effect
Caused by gases trapping heat in the atmosphere
As light from the sun hits Earth, some of it gets reflected into space
90% of these rays are absorbed by these greenhouse gases and reflected back on Earth, heating the surface and atmosphere
Advantages
Helps to regulate the Earth's temperature to make sure it is not too cold, allowing both humans and animals alike to live comfortably in a warmer environment
Heats up the Earth so water does not turn into ice, making sure that there is enough water to sustain life
Greenhouse gases such as ozone reduce UV radiation from the sun hitting Earth
Provides carbon dioxide to plants so they can photosynthesize and produce oxygen for humans and animals
Disadvantages
Causes global warming
Causes the sea levels to rise due to melting ice
Creates extreme weather due to climate change
Can harm marine life as greenhouse gases are absorbed by water, causing their pH levels to rise which will affect underwater ecosystems
Can be expensive in the long run as the greenhouse effect causes sea levels to rise, which means governments need to spend more money constructing systems to protect coastal areas
Oxygen/Carbon cycle
Plants create oxygen
Animals breathe out carbon dioxide
Decaying matter releases carbon dioxide
There is always a balance between oxygen and carbon dioxide
Layers of the atmosphere
Stratosphere
The second level of the atmosphere. Also where the ozone layer is located. (end of troposphere - 50 km)
Mesosphere
The third level of the atmosphere. Temperatures get lower the higher you get. (end of stratosphere - 85 km)
Troposphere
The lowest level of the atmosphere. Also where wind occurs and clouds are at. (surface level - 12 km)
Thermosphere
The fourth level of the atmosphere. Temperatures are extreme, freezing at night and extremely hot in the day. (end of mesosphere - 500km)
Exosphere
The last level of the atmosphere. Spaceships and the ISS orbit around the earth here. Can extend and retract depending on conditions. (end of thermosphere - space)
Climate/Climate change
Weather
The day to day state and humidity levels of the atmosphere
Climate
The weather patterns of a specific area surveyed over 30 years
Climate change causes
Caused by the greenhouse effect
Human activity
Carbon emissions