Now that you have covered the visible surface of the earth, we should have look at interior and what is beneath the surface.
Earths Structure
Like the atmosphere of the earth, the interior also has layers which has their own functions and characteristics. But comparing this to the atmosphere, we can say that both of them have extreme characteristics that prove that humans cannot settle in these region. The atmosphere of the earth was said to be extremely cold but on the other hand, the earths interior is burning hot. Even though we do not have the tools to look directly underneath the earths surface, we can analyse the waves that are exerted from the interior. This method has allowed us to discover that the earths interior consists of 4 layers, with some that have sub layers. These layers from outwards is the crust, mantle, outer core, and inner core.
- Oceanic Crust- the crust that beds the ocean. This crust consists of denser rock and serves as the ocean bed for oceans.
- Asthenosphere - a layer of softer, weaker rock that can flow slowly
- Mesosphere- the lower layer of the mantle, stiffer rock
- Crust- the outermost layer of the Earths interior that extends to almost 40km underground. This layer is mostly consisted of rock and is said to be liveable. Indeed the crust is liveable because we are living on this layer. Most of the earths organisms settle in the crust which makes it a very liveable place. But within this layers are two sub categories which are the continental crust and oceanic crust.
- Oceanic Crust- the crust that beds the ocean. This crust consists of denser rock and serves as the ocean bed for oceans.
- Mantle- the region of hot solid rock that extends for almost 3000km. Pressure and temperature in this region increases as the depth increases, this makes this region almost impossible to live in. This region consists of another 3 layers which are lithosphere, asthenosphere, and mesosphere.
- Asthenosphere - a layer of softer, weaker rock that can flow slowly
- Mesosphere- the lower layer of the mantle, stiffer rock
- Core- a large sphere of metal, composed of iron, nickel. This region experiences 3.5 million times more pressure than the earths surface making it impossible for human beings to live in. Adding to this, the temperature is 5500 degrees which is equivalent to the suns surface. But within this layer lies two other layers which are the outer and inner core.
Minerals
The little hard object you may have seen lying on the ground, or even seen in a museum is a mineral. A mineral is a naturally occurring substance with a definite chemical composition. But the difference between solids that you see called a rock is its chemical structure. Numerous minerals make up a rock which can be found almost anywhere. But a mineral is a solid that has a definite chemical compound. But to determine a mineral, you have to consider these aspects of the mineral. Structure, colour, streak, luster, density, fracture/cleavage, and a few other minor aspects.
Minerals have other characteristics such as the reaction to chemicals or magnets, the reaction when scratched onto other rocks, refraction of the light, and electrical charges in a rock. Even though this may sound a lot, there are more than this that can determine the minerals chemical structure.
- Structure- In each type of mineral, the atoms are arranged in a particular geometric shape or crystal structure therefore we can determine the mineral by its structure. Some minerals are shaped like cubes, sheet, needle, thread. also differs in size.
- Colour- the appearance of the mineral due to the chemical compounds. Slight change in composition can change the colour.
- Streak- The colour of the minerals powder. You scrape the mineral on a piece of unglazed streak plate the powder of the mineral is visible. The colour of the streak can defer based on the mineral.
- Luster- The way a mineral reflects light (general appearance and how shiny it is). Some rocks might be smooth and shiny, some might be rocky and not so shiny.
- Density- The weight of the mineral depends on the composition of the mineral, heavier the atomic mass the bigger the density.
- Hardness- the resistance of a mineral to scratching. The hardness is determined by the Mohs scale from 1(hard)-10(soft). Hardness is determined by systematic scratching and comparing it with other minerals. If it can scratch 5 and can't scratch 6 it is about 5.5
- Fracture- It is how the mineral breaks. When quartz is broken, it has a curved shell shaped fracture. Determined by the crystalline structure and the atomic bonds of the crystal.
- Cleavage- type of fracture in which minerals tend to split along regular and well defined planes.
Minerals have other characteristics such as the reaction to chemicals or magnets, the reaction when scratched onto other rocks, refraction of the light, and electrical charges in a rock. Even though this may sound a lot, there are more than this that can determine the minerals chemical structure.
Rocks and Rock cycle
Rocks may have the characteristic to be hard and rigid that make us think that it can never change. But the truth is, rocks goes through a very timely process where they change their form. This cycle is called the rock cycle where they transform themselves into various forms depending on the factors they are exposed to. The rocks can be categorised into three categories which are Igneous rocks, Sedimentary rocks, and metamorphic rocks, and are based on where they form.
- Chemical Rocks- When rain dissolve minerals, they flow down with the flow, then reached the ocean. In the ocean, the water around it evaporates the minerals becomes concentrated, thus creating a rock. This usually happen on dry basins where the water had evaporated.
- Organic Rocks- rocks such as Coral, shells, clams are made from calcium carbonate, when the organisms die, they sink into the bottom, then it gets compacted and cemented. This then results in the creation of rocks.
Rocks are constantly changing forms and are never the same. We may see rocks as never changing objects but in reality they are changing form very slowly. The diagram represents the cycle in which rocks can transform.
- Igneous Rocks - rocks that form from magma, mixture of molten rock, gas and water vapour. Forms when magma cools on or in the surface. The chemical composition of the rock can determine by the colour of the rock because the magma consists of different chemical which has a distinct able colour when cooled. If the rock forms underground it is called intrusive. An intrusive rock is usually has a coarse and grained texture. On the other hand a extrusive rock is a rock that forms on the surface and has a fine grained texture but relatively small compared to the intrusive rock. This is because extrusive rocks cool faster than intrusive rock, giving them a smaller time to expand.
- Sedimentary Rock- Rocks that are rocks that form over time as sediment are squeezed and cemented. In this category of rock, there is another 3 more which are clastic, chemical, and organic rocks.
- Chemical Rocks- When rain dissolve minerals, they flow down with the flow, then reached the ocean. In the ocean, the water around it evaporates the minerals becomes concentrated, thus creating a rock. This usually happen on dry basins where the water had evaporated.
- Organic Rocks- rocks such as Coral, shells, clams are made from calcium carbonate, when the organisms die, they sink into the bottom, then it gets compacted and cemented. This then results in the creation of rocks.
- Metamorphic rocks- Formed when rocks are transformed due to heat pressure or chemical reactions. This is called metamorphism. Metamorphism can enlarge or shrink rocks and have the capability to change the minerals of a rock. Rocks can also change texture due to compression, which changes the appearance of the rock. When a rock is compressed and layered due to the pressure, and is layered in a manner that it is arranged properly, it is called a foliated rock, but if it is layered randomly it is called a un-foliated rock.
Rocks are constantly changing forms and are never the same. We may see rocks as never changing objects but in reality they are changing form very slowly. The diagram represents the cycle in which rocks can transform.
Plate tectonics
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Continents and land masses all lie under a plate. Just like a piece of bread on a plastic plate, but the plates that the land masses lie on are enormous and cover huge areas. The plates that the land masses lie on are called plates (haha), the plates are pieces of the lithosphere and move above the asthenosphere. There are numerous plates in which landmasses lie on and when these plates collide due to the convection of the mantle, the land masses shake. The title of this section "tectonic plates" is a theory in which pieces of Earth`s lithosphere, called plates moves about slowly on top of the asthenosphere. This theory explains the formation and movement of Earths plates. The movement of landmasses such as continents is called continental drift. When scientists discovered organisms in a region it shouldn't be, and lands fitted like a jigsaw puzzle, they deduced that there was once a single continent. This single continent broke away due to the continental drift and became what it is today. The movement of plates and discoveries of organisms that do not belong in the region proved that there was once a super continent where all lands were together.
As explained in pervious sections, rocks are constantly being created and destructed, this applies to the ocean beds in the ocean. The ocean bed is constantly being renewed and destructed, this is due to the mid ocean ridges which are chains of underground volcanic mountains which are created in the cracks of the crust. This mid ocean ridge is the longest mountain range in the earth and is found in most of the oceans. The mid ocean ridge has the function of creating new rocks while destructing old and worn out rocks or the formation of oceanic crust. The process in which the oceanic crust is created in the mid ocean ridge is called the sea floor spreading. Because new crust is forming, the old ones need to be destroyed, therefore, the old crust subduct into the mantle. This region in which subduction occurs is the called the subduction zone, this usually forms in the edges of the oceanic plates. The depression in which subduction creates is called a trench. In the past history, the poles of the earth was reversed therefore the they are stripes on the ocean bed. It was created because the rock crystals were forced to line up in a certain way before the rock solidified. Another feature scientist found in the ocean crust was the radioactive dating, it showed that the rocks that were younger were near the ridge. When the mid ocean ridges create new crust due to the convection of the mantle by the core, the old crust which are getting pushed away by the new crust subduct into the mantle. The rock that subduct melt and becomes magma, and repeats the cycle of rock formation if they reach the surface. This cycle usually takes about 200 million years to complete. This shows that the earth may seem to not move but they are slowly changing form.
This section had briefly introduced the theory of tectonic plates in previous paragraphs, but the theory is more than what it on the outside. The theory suggests that the plates are moving at different directions at different speeds, this suggests that they are still moving to this day. The movement of plates would not have happened without the convection of the mantle. The movement of heated magma moving upward is due to the gradual cooling if its interior suggesting that the core is cooling down. The second source of energy is the decay of radioactive isotopes that are distributed throughout the mantle. The heating of the mantle due to the cores heat causes convection which then results in the creation of new crust in the mid ocean ridge.
We have talked about the movement of plates, but we have not yet covered how they collide. The earths surface is completely covered by plates therefore there are always collisions between each other. There are currently 12 plates on the surface and are constantly colliding each other. The region where they are colliding is called the plate boundaries. Each of the plates move differently therefore they collide different. They are 3 types of boundaries of which are convergent, divergent and transform boundaries.
As explained in pervious sections, rocks are constantly being created and destructed, this applies to the ocean beds in the ocean. The ocean bed is constantly being renewed and destructed, this is due to the mid ocean ridges which are chains of underground volcanic mountains which are created in the cracks of the crust. This mid ocean ridge is the longest mountain range in the earth and is found in most of the oceans. The mid ocean ridge has the function of creating new rocks while destructing old and worn out rocks or the formation of oceanic crust. The process in which the oceanic crust is created in the mid ocean ridge is called the sea floor spreading. Because new crust is forming, the old ones need to be destroyed, therefore, the old crust subduct into the mantle. This region in which subduction occurs is the called the subduction zone, this usually forms in the edges of the oceanic plates. The depression in which subduction creates is called a trench. In the past history, the poles of the earth was reversed therefore the they are stripes on the ocean bed. It was created because the rock crystals were forced to line up in a certain way before the rock solidified. Another feature scientist found in the ocean crust was the radioactive dating, it showed that the rocks that were younger were near the ridge. When the mid ocean ridges create new crust due to the convection of the mantle by the core, the old crust which are getting pushed away by the new crust subduct into the mantle. The rock that subduct melt and becomes magma, and repeats the cycle of rock formation if they reach the surface. This cycle usually takes about 200 million years to complete. This shows that the earth may seem to not move but they are slowly changing form.
This section had briefly introduced the theory of tectonic plates in previous paragraphs, but the theory is more than what it on the outside. The theory suggests that the plates are moving at different directions at different speeds, this suggests that they are still moving to this day. The movement of plates would not have happened without the convection of the mantle. The movement of heated magma moving upward is due to the gradual cooling if its interior suggesting that the core is cooling down. The second source of energy is the decay of radioactive isotopes that are distributed throughout the mantle. The heating of the mantle due to the cores heat causes convection which then results in the creation of new crust in the mid ocean ridge.
We have talked about the movement of plates, but we have not yet covered how they collide. The earths surface is completely covered by plates therefore there are always collisions between each other. There are currently 12 plates on the surface and are constantly colliding each other. The region where they are colliding is called the plate boundaries. Each of the plates move differently therefore they collide different. They are 3 types of boundaries of which are convergent, divergent and transform boundaries.
- Convergent boundaries- where plates come together and collide. This form of collision usually creates a mountainous region. When two boundaries push each other upward, they create a mountainous region.
- Divergent boundaries- where plates move away from each other
- Transform boundaries- The plate slide against another, nothing is created nor destroyed
Earthquakes
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I believe you may have already felt the surroundings shake and tremble a bit in the few days you have been here. Or you may not have felt anything. The trembles that you may felt are results of the movement between two plates caused near boundaries, therefore if you are not near a plate boundary you do not experience any of this. This whole phenomena is called an earthquake and can cause severe damages to buildings and people. I believe you may have already felt the surroundings shake and tremble a bit in the few days you have been here. Or you may not have felt anything. The trembles that you may felt are results of the movement between two plates caused near boundaries, therefore if you are not near a plate boundary you do not experience any of this. This whole phenomena is called an earthquake and can cause severe damages to buildings and people.
Earthquakes is the movement of Earth's lithosphere that occurs when rocks in the lithosphere suddenly shift, releasing stored energy. Energy released in a earthquake is carried by waves called seismic waves. These seismic start when the stress force over powers the strength of the rock, an earthquake occurs. The point in which the earthquake begins is called the focus and the land directly above it is called the epicentres. Depending on the rocks stress capacities, the earthquakes magnitude can differ and can cause different amounts of damage. Earthquakes magnitude depends on many factors such as the temperature, composition, and density of the rocks they pass through but the same thing is that during this process, potential energy is converted to kinetic energy, energy that can do harm.This can cause many changes in the land which are faults and folds.
There are 3 types of seismic waves that the movement of plates can cause which are P waves, S waves, and surface waves. Each of them have their own characteristics and can cause different forms of trembles.
These magnitude for these waves can differ depending on the focus, and the wave therefore a measurement system has been put to place to categorise the magnitude of the earthquake. But to measure and analyse an earthquake, scientists have invented a measuring device called the seismograph which can detect and record seismic waves. Adding to this the recorded data can pinpoint the epicentres of the earthquake. The recorded data does not mean anything until applied into a scale. There are 3 types of scales in which earthquakes can be categorised. These three are richter scale, moment magnitude scale, and modified Mercalli scale.
Through extensive research and analysis of earthquakes, scientists have discovered many new information regarding the earth. For instance, they have discovered that the outer core is liquid because S waves cannot pass through liquid. Another discovery that was made is that the core is mostly iron, because P waves travel through it the same speed that it does in a lab.
Earthquakes is the movement of Earth's lithosphere that occurs when rocks in the lithosphere suddenly shift, releasing stored energy. Energy released in a earthquake is carried by waves called seismic waves. These seismic start when the stress force over powers the strength of the rock, an earthquake occurs. The point in which the earthquake begins is called the focus and the land directly above it is called the epicentres. Depending on the rocks stress capacities, the earthquakes magnitude can differ and can cause different amounts of damage. Earthquakes magnitude depends on many factors such as the temperature, composition, and density of the rocks they pass through but the same thing is that during this process, potential energy is converted to kinetic energy, energy that can do harm.This can cause many changes in the land which are faults and folds.
- Faults- break in a mass of rock along which movement occurs
- Folds- a bend in layers of rocks. This happens when the rocks are squeezed but do not break.
There are 3 types of seismic waves that the movement of plates can cause which are P waves, S waves, and surface waves. Each of them have their own characteristics and can cause different forms of trembles.
- P Waves- longitudinal waves (primary waves), waves that act by compression and release therefore the particles move the way the energy is directed. This form of the seismic wave is the fastest and can travel through liquid and solid.
- S Waves- transverse waves (secondary waves), particles vibrate at right angles to the direction the waves moves. Unlike P Waves it does not travel through liquid.
- Surface Waves- develop when seismic waves reach earth's surface. This wave travels transversely or roll through particles, and can create the strongest waves.
These magnitude for these waves can differ depending on the focus, and the wave therefore a measurement system has been put to place to categorise the magnitude of the earthquake. But to measure and analyse an earthquake, scientists have invented a measuring device called the seismograph which can detect and record seismic waves. Adding to this the recorded data can pinpoint the epicentres of the earthquake. The recorded data does not mean anything until applied into a scale. There are 3 types of scales in which earthquakes can be categorised. These three are richter scale, moment magnitude scale, and modified Mercalli scale.
- Richter Scale- rates earthquakes based on the length and amplitudes. This scale is currently rarely used.
- Moment Magnitude scale- measures the amount of energy released by an earthquake. Most common way of measuring an earthquake
- Modified Mercalli Scale- a system of rating an earthquake, based on the intensity of ground shaking and the damage.
Through extensive research and analysis of earthquakes, scientists have discovered many new information regarding the earth. For instance, they have discovered that the outer core is liquid because S waves cannot pass through liquid. Another discovery that was made is that the core is mostly iron, because P waves travel through it the same speed that it does in a lab.
Volcanoes
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Another phenomena that occurs when tectonic plates move is a mountain that erupts molten rock. This mountain is called a volcano and like the earthquake, it can cause severe damages to many factors of the earth. The convection of magma under the crust causes the volcano to experience intense pressure which then can lead to the eruption of the mountain. When the magma is pushed upward through the volcano due to convection, the volcano experiences immense pressure and can then release the magma. The suns core is responsible for providing the magma with energy to rise above therefore we are able to analyse what is happening in the core. Even though convection may the primary reason of an eruption, the movement of plates is another factor of eruption. Volcanoes are commonly found near plate boundaries and where oceanic plates subduct into the crust. The Ring of Fire is a region that has a lot volcano due to the many plate boundaries.
A volcano has a process before and after an eruption, each step can take hundreds of years. This process consists of the accumulation of magma, eruption, and the formations created due to the eruption.
Even though all the hot and orange magma may seem identical, they can differ. Thus chagning the way a volcanoes erupts. The viscosity of a magma is the resistance to flow determined by temperature, water content, and silica. The higher the temperature, the lower the resistance to flow. More water content makes lower resistance to flow. High silica makes higher viscosity. The viscosity of the magma determines the form of eruption therefore there are 2 primary types a volcano can erupt which are quiet and explosive.
The eruption itself may be spectacular but the formations that a volcanic eruption can cause is remarkable. Eruptions can create volcanoes, rocks, and even change the land. There are 3 categories of volcanoes which are shield, cinder, and composite volcanoes. Each of these volcano have different characteristics and depend on how they form.
Other formations an eruption can create are rocks. Depending on the magmas composition and many factors, therefore many forms of rocks form such as the obsidian, lava bomb, and pumice
Besides rocks, magma can form many different structures on earth such as igneous volcanoes. Volcanoes that form
when magma does not reach the surface, and cools down in the crust. This can form structures such as the volcanic necks. A volcanic neck is a tall structure formed when the magma cools in the pipe.
Even though it may have felt as we have covered the whole universe, we have only barely scratched the surface of what the earth hold for us. Our earth is more than what has been written here and is a spectacular place. I hope you enjoy your time on earth and hope that you will leave earth with a good memory.
A volcano has a process before and after an eruption, each step can take hundreds of years. This process consists of the accumulation of magma, eruption, and the formations created due to the eruption.
- Magma is collected in the magma chamber. When the magma receives sufficient pressure, they erupt.
- Magma from the chamber rises to the surface in a channel called a pipe
- The magma is then thrown outside through the vent, a opening in the ground where magma escapes.
- Formations- Crater, Caldera
- Crater- a bowl shaped pit on a top of the mountain, created by explosions
- Caldera- when magma chambers empty, and the land collapses inward
Even though all the hot and orange magma may seem identical, they can differ. Thus chagning the way a volcanoes erupts. The viscosity of a magma is the resistance to flow determined by temperature, water content, and silica. The higher the temperature, the lower the resistance to flow. More water content makes lower resistance to flow. High silica makes higher viscosity. The viscosity of the magma determines the form of eruption therefore there are 2 primary types a volcano can erupt which are quiet and explosive.
- Quiet Eruptions- very hot, low viscosity, lava can travel long distances.
- Explosive Eruptions- high in silica=higher viscosity. Therefore the pipes can clog up causing a sudden burst. This form of eruption causes lava to solidify quickly therefore creating ashes and rocks.
The eruption itself may be spectacular but the formations that a volcanic eruption can cause is remarkable. Eruptions can create volcanoes, rocks, and even change the land. There are 3 categories of volcanoes which are shield, cinder, and composite volcanoes. Each of these volcano have different characteristics and depend on how they form.
- Shield volcano- their eruption consists of slow flowing lava, flat volcano that extends for a long distance.
- Cinder Volcano- small and steep. Form from ashes and cinder
- Composite Volcano- tall and steep. From from layers of lava and ashes.
Other formations an eruption can create are rocks. Depending on the magmas composition and many factors, therefore many forms of rocks form such as the obsidian, lava bomb, and pumice
- Obsidian- dense glass rock, form when cooled very quickly
- Lava bomb- Created when a glob of lava is exploded into air
- Pumice- light sponge like rock
Besides rocks, magma can form many different structures on earth such as igneous volcanoes. Volcanoes that form
when magma does not reach the surface, and cools down in the crust. This can form structures such as the volcanic necks. A volcanic neck is a tall structure formed when the magma cools in the pipe.
Even though it may have felt as we have covered the whole universe, we have only barely scratched the surface of what the earth hold for us. Our earth is more than what has been written here and is a spectacular place. I hope you enjoy your time on earth and hope that you will leave earth with a good memory.