I think I can demonstrate my knowledge of the plate-tectonic theory because I can explain all the laws and theories of the plate tectonic theory well.
The plate-tectonic theory is composed of many ideas.
Purpose of theory:
-may explain the continental drift
-may explain
earthquakes and
volcanoes
-may explain landforms
First, there's 4 layers in the earth: The Crust, the mantle, the outer core, and the inner core.
First the Inner core ,which is the last layer, is a ball that is made out of solid metal. It's really hot in there. Since it's so hot, you should be asking yourself why. Well, it is solid because since there's so much pressure from the layers in top of it, the metal particles of that core can't spread out at all (maybe really, really little motion). So since the metal particles can't move, it's a solid.
Next, it's the outer core. This core it's made out of liquid metal. The only main purpose of this core is that it produces a magnetic field.
After this layer, the next one is the mantle, which is the thickest layer. This layer is made out of
magma and
convection currents. The magma is produced there because there's so much heat there and because there's not as much pressure from the layers because there's only one layer in top of it. This heat also makes the convection currents in the mantle. First on the bottom of the mantle is hotter than the top of the mantle, so the magma in the bottom will be less dense than the one in the top. But according to the particle theory, less dense things go on top. So since the magma in the bottom of the mantle is less dense, it will try to go up. When it goes up, it will cool down because is not as hot in the top. So that magma when it cools down will go down and then it will get heat up again and go up again and so that is how that convection currents are created.
Next is the crust, which is the last and the smallest layer of the earth. This layer is made out of rocks, continents, and plates.
You should be asking yourself how do scientists know this topic about layers? Well, because scientists hit in the ground some waves of energy named
seismic waves. This types of waves can cross the whole inside of the world. When some of this waves crossed the world's inside, they hit something in the earth while crossing it, then came back out in another place. Scientists studied this well and they came up with the solution of the earth layers.
Explaination of continental drift(continental drift m
eans when continents are moving):
First, plates have ridges (one big crack) and the two sides move to opposite directions.Why do plates move? Because in the mantle, like I said before, it has convection currents that makes force the plate. And since there's a crack in a plate, it will move those 2 sides of the crack apart. And when the cracks are moving, the plate is moving.
That happens at mid-atlantic ridge. There's a plate there. That plate moves to the left. When it moves to the left, it also moves t
he continent America. On the right of America, there's a
hot spot. Hot Spots don't move. So when the plate with the continent moves, it will crash with that hot spot. The hot spot is denser than the plate that is moving. So the hot spot will sink in the plate and turn into magma in the mantle. But don't think that the earth is sinking because the plate in the mid atlantic ridge is expanding (making more land).
This might support the idea of Pangea.
There's a lot of evidenceof the pangea idea.
Some evidence are:
The
fossils found in south america and africa
The puzzle look the continents have
The laws of the plate tectonics theory
The Climate
The Landform locations
The
Mid-Atlantic ridge having a shape of the continents
Another recent evidence was that rocks that are closer to the
mid atlantic ridge are younger than the rocks found closer to America's right side and Europe/Africa's left side. This type of rocks are
ignous rocks(magma rocks). The explanation for this is that there's a volcano inside the Mid-Atlantic Ridge so when the volcano threw magma(and turned into rock), the rock fell in the sea floor and was pushed to the side far away by the water. Then the volcano threw more magma rock and was moved by the water, but not as faraway as the other ignious rock was. How do we know this? Because when ships were drilling in the ocean for oil, examples of rocks were found in the drill and then scientists started to study those rocks and then they came up with that idea
.
Well, going back to the plates topic, there's 3 types of boundaries when plates are moving.
They are:
Transform boundary
Converging boundary
Diverging boundary
A
diverging boundary is when the plate's ridge seperates, forced by the conjection currents.
A
converging boundary is when the two sides of the plate's ridge hits and crashes. This might cause earthquakes.
A
transform boundary is when 2 plates scracth side to side.
Subduction occurs here because they're scratching both plates side to side. When they scratch(because they're not smooth and really flat), both plates might get stuck, but then the pressure from the conjection currents pushes those plates to not be stuck anymore. But when the pressure moves them, they quake and this causes an earthquake.
This ideas and laws I've exposed in this blog unite and form the plate-tectonic theory.
