Convection and the Mantle

The movement of energy from a warmer object to a cooler object is called heat transfer.

There are 3 types of heat transfer:

Radiation

Conduction

Convection

Density - a measure of how much mass there is in a given volume

Convection Current - the flow that transfers heat within a fluid

Convection currents work by warmer, less dense, fluid rising and colder, more dense, fluid sinking

***These 3 things set convection currents in motion***

Heating and cooling of a fluid

Changes in the fluid's density

The force of gravity

Heat from the core and the mantle itself cause convection currents inside the mantel

The middle portion of the mantel, the asthenosphere, is plastic-like due to this heat

As lower parts of the asthenosphere are heated, they become less dense and begin to rise

When this section reaches the top, it spreads out, cools off, and begins to sink back to the bottom

When the section of asthenosphere reaches the top it transfers heat to the lithosphere through conduction

Convection currents also occur inside the outer core

The outer core is mostly liquid iron and nickel

These currents cause Earth's magnetic fields