When Alfred Wegener an initial proposed the continents had actually drifted into their current positions, couple of people listened. After all, what feasible force can move something as large as a continent?


While he didn"t live long enough to it is in vindicated, Wegener"s hypothesized continental drift evolved in the concept of plate tectonics. One device for moving the continents requires convection currents in the mantle.

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Heat moves from locations of greater temperature to locations of lower temperature. The three mechanisms for warmth transfer room radiation, conduction and convection.


Radiation moves power without contact in between particles, favor the radiation of power from the sun to the planet through the vacuum that space.


Conduction transfers energy from one molecule to another through contact, without particle movement, as as soon as sun-warmed land or water heats the air straight above.


Convection occurs v the movement of particles. As particles come to be heated, the molecules relocate faster and faster, and as molecules move apart, thickness decreases. The warmer, less dense material rises compared to the bordering cooler, higher density material. When convection typically refers come the liquid flow developing in gases and also liquids, convection in solids favor the mantle occurs however at a slow rate.


Heat in the mantle originates from the Earth"s molten external core, decay of radioactive aspects and, in the top mantle, friction native descending tectonic plates. The warmth in the outer core outcomes from residual energy from the Earth"s formative events and the energy generated through decaying radioactive elements. This warmth warms the base of the mantle to an approximated 7,230°F. In ~ the mantle-crust boundary. The mantle"s temperature is an approximated 392°F.


The temperature difference in between the upper and also lower borders of the mantle requires heat transfer come occur. If conduction seems the more obvious technique for warm transfer, convection likewise occurs in the mantle. The warmer, less thick rock product near the core slowly moves upward.


Relatively cooler absent from greater in the mantle gradually sinks toward the mantle. As the warmer material rises, it likewise cools, ultimately pushed beside by warmer increasing material and sinking back toward the core.


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


Plate tectonics provides an explanation for Wegener"s drifting continents. Bowl tectonics, in brief, says that the Earth"s surface is broken into plates. Each plate is composed of slabs of lithosphere, the rocky external layer the the Earth, that includes the crust and uppermost mantle. This lithospheric pieces relocate on height of the asthenosphere, a plastic layer in ~ the mantle.


Convection currents in ~ the mantle carry out one potential driving pressure for plate movement. The plastic movement of the mantle product moves favor the circulation of mountain glaciers, transporting the lithospheric plates along as the convection motion in the mantle move the asthenosphere.


Slab pull, slab (trench) suction and ridge push may likewise contribute come plate movement. Slab pull and also slab suction average that the massive of the descending plate pulls the trailing lithospheric slab across the asthenosphere and also into the subduction zone.


Ridge push says that together the much less dense new magma rising into the facility of oceanic ridges cools, the thickness of the material increases. The increased density accelerates the lithospheric plate towards the subduction zone.


Heat transfer likewise occurs in the atmosphere and hydrosphere, come name two layers of earth in which convection currents take place. Radiant heater from the sun warms the surface of the Earth. The warmth transfers to the nearby air massive via conduction. The warmed wait rises and also is replaced by cooler air, developing convection currents in the atmosphere.


Similarly, water warmed by the sun transfers warm to reduced water molecules with conduction. As air temperature fall, however, the warmer water below moves ago toward the surface and the colder surface water sinks, creating seasonal convection currents in the hydrosphere.


In addition, the Earth"s rotation moves heat water from the equator towards the poles, bring about ocean currents that move warm from the equator to 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 prior to returning to school to earn her multiple subject teaching credential. Karen taught center school scientific research for over two 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 steam classes.