When Alfred Wegener very first proposed the continents had drifted right into their existing positions, few people listened. After ~ all, what possible force could move other as large as a continent?


While the didn"t live long sufficient to be vindicated, Wegener"s hypothesized continental drift developed in the theory of key tectonics. One device for moving the continents involves convection currents in the mantle.

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Heat moves from areas of higher temperature to areas of reduced temperature. The 3 mechanisms for warmth transfer space radiation, conduction and also convection.


Radiation moves power without contact between particles, like the radiation of power from the sunlight to the earth through the vacuum the space.


Conduction transfers power from one molecule to another through contact, without bit movement, as when sun-warmed land or water heats the air directly above.


Convection occurs with the movement of particles. As particles become heated, the molecules relocate faster and faster, and also as molecules relocate apart, density decreases. The warmer, less thick material rises compared to the neighboring cooler, higher density material. While convection usually refers come the fluid flow emerging in gases and liquids, convection in solids favor the mantle occurs however at a slower rate.


Heat in the mantle comes from the Earth"s molten external core, degeneration of radioactive facets and, in the top mantle, friction indigenous descending tectonic plates. The warm in the outer core outcomes from residual power from the Earth"s developmental events and the power generated through decaying radiation elements. This warmth warms the basic of the mantle to an approximated 7,230°F. At the mantle-crust boundary. The mantle"s temperature is an estimated 392°F.


The temperature difference between the upper and lower borders of the mantle requires heat transfer come occur. While conduction seems the much more obvious method for warm transfer, convection also occurs in the mantle. The warmer, less thick rock material near the core progressively moves upward.


Relatively cooler rock from greater in the mantle slowly sinks toward the mantle. Together the warmer product rises, it likewise cools, eventually pushed next by warmer increasing material and sinking back toward the core.


Mantle product flows slowly, like thick asphalt or mountain glaciers. If the mantle material remains solid, the heat and also pressure allow convection currents to move the mantle material. (See resources for a mantle convection diagram.)


Plate tectonics provides an explanation because that Wegener"s drifting continents. Bowl tectonics, in brief, claims that the Earth"s surface is damaged into plates. Each plate is composed of slabs that lithosphere, the rocky outer layer of the Earth, that contains the crust and also uppermost mantle. This lithospheric pieces move on top of the asthenosphere, a plastic layer in ~ the mantle.


Convection currents within the mantle carry out one potential driving force for key movement. The plastic activity of the mantle material moves favor the flow of hill glaciers, delivering the lithospheric plates along as the convection movement in the mantle move the asthenosphere.


Slab pull, slab (trench) suction and also ridge push may additionally contribute to plate movement. Slab pull and also slab suction median that the fixed of the descending plate traction the rolling lithospheric slab across the asthenosphere and into the subduction zone.


Ridge push says that together the much less dense brand-new magma rising into the facility of oceanic ridges cools, the density of the material increases. The enhanced density increases the lithospheric plate toward the subduction zone.


Heat transfer likewise occurs in the atmosphere and also hydrosphere, come name two layers of planet in i m sorry convection currents take place. Radiant heating from the sun warms the surface of the Earth. That warmth transfers to the nearby air fixed via conduction. The warmed waiting rises and is changed by cooler air, developing convection currents in the atmosphere.


Similarly, water warmed by the sun transfers warm to lower water molecules v conduction. As air temperature fall, however, the warmer water listed below moves back toward the surface and the cooler surface water sinks, producing seasonal convection currents in the hydrosphere.


In addition, the Earth"s rotation moves warm water native the equator towards the poles, leading to ocean currents that move heat from the equator come the poles and also pushes cold water from the poles toward the equator.

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Karen earned she Bachelor of science in geology. She worked as a geologist because that ten years before returning to college to earn her multiple topic teaching credential. Karen taught center school scientific research for over 2 decades, earning her grasp of arts in Science education (emphasis in 5-12 geosciences) follow me the way. Karen now designs and teaches science and heavy steam classes.