Convection Currents and the Earth's Mantle

Convection Currents and the Earth's Mantle Visual Arts Geography Social Studies STEM

The Earth’s mantle is made-up of very hot, dense rock.  Scientists believe that it has the consistency of asphalt and that it moves.

There are wide temperature differences between the top of the mantle (about 1600° F) and the bottom of the mantle (about 4000° F).

The molten mantle moves.  Scientists think it flows like asphalt.

So ... here are a few questions.

Q:  What causes the thick material to move, like thick soup boiling in a pan? 

A:  Convection currents.

Q:  What are convection currents? 

A:  Convection currents happen when material which is really hot (in the deepest part of the mantle) rises (because hot materials rise).  After it rises, the hot material cools (because it’s no longer in the really hot place), and then sinks (because cooler materials sink).  

So ... this process of rising and sinking produces a “convection current.”  It’s the same process we see when we’re cooking something really thick in a saucepan. 

If we apply that process to the Earth’s mantle, we can understand why there’s convection-current movement there, too.  Scientists believe that when convection currents flow in the Earth’s mantle, they are able to move the Earth’s tectonic plates. 

Think of the plate-movement process like a slow-moving conveyor belt.  If a box is placed on the moving conveyor, the box moves with the belt.  The conveyor belt is like the molten mantle while the tectonic plates are like boxes on the belt.

Media Credits

Image from John Wiley.  Copyright, John Wiley, all rights reserved.  Image used here as fair use for educational purposes.


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"Convection Currents and the Earth's Mantle" AwesomeStories.com. Oct 07, 2013. Sep 16, 2019.
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