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Course: American Museum of Natural History > Unit 4
Lesson 1: Plate TectonicsComputer Model of Mantle Convection
Scientists study mantle convection, or the flow of hot rock in the Earth's deep interior, in order to better understand how this flow shapes the surface of the Earth. When a solid, liquid, or gas is heated, it expands, becomes less dense, and rises. When it cools, it contracts, becomes more dense, and sinks. The circulation that results from hot, rising material and cool, sinking material is known as convection. Convection makes the Earth dynamic. Created by American Museum of Natural History.
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If the lava is near the inner core, how does the lava go through the outer core mantle and crust?(4 votes)
Lava is not near the inner core. Convection in the outer mantel transfers heat, which melts the plates in subduction zones, producing lava.(1 vote)
- Are we assuming that the inner core, since it's believed to be solid, undergoes conduction, and has a more uniform temperature distribution?(1 vote)
00:45i still dont get how it is moving(0 votes)
Lithospheric plates move by convection cells, which are particular spots where convection currents carry heat from the Earth's core, still hot from 4.5 billion years of radioactive decay formed by the accretion of heavy metals. These convection currents move lithospheric plates through three main hypotheses:
1. convection drag - the idea that when magma moves to the surface, where the plates are- it cools down and moves to one side of the plate, dragging it along with it as it moves.
2. slab pull - the idea that when a subducting oceanic plate is being pulled under the continental plate, the subduction occurs and often speeds up because of slab pull. Imagine a metal chain that you lay over the side of a table. If you pull the chain down slightly off of the table, the rest of it will quickly follow the fall. This is like a subducting oceanic plate, but on a much larger scale.
3. ridge push - the idea that when new magma is formed at mid-ocean ridges it pushes either plate out to the side of it, forcing the plates to move.(3 votes)
- What is an Isoviscous model?(0 votes)
00:45