What is the main method of heat transfer from the core to the crust of earth? A. Conduction B. Convection C. Radiation
Conduction
The main method of heat transfer from the core to the crust of the Earth is through convection. To understand why convection is the primary mode of heat transfer in this context, let's break down the options:
A. Conduction: Conduction is the process of heat transfer through direct contact between particles or objects. While conduction does occur in the Earth, it is not the primary method of heat transfer from the core to the crust. This is because the Earth's crust is relatively rigid and does not allow for efficient conduction of heat over long distances.
B. Convection: Convection is the process of heat transfer through the movement of a fluid, either gas or liquid. In the Earth's mantle, which is a semi-fluid layer between the core and the crust, heat is transferred primarily through convection. The heat generated from the core heats up the mantle, causing it to become less dense and rise towards the surface. As the hot mantle rises, it transfers heat to the cooler crust, which causes the crust to heat up as well. At the same time, the cooler crust sinks back into the mantle, completing the cycle. This continuous movement of the fluid in the mantle due to heating and cooling is what drives convection.
C. Radiation: Radiation is the process of heat transfer through the emission and absorption of electromagnetic waves. While radiation does play a role in the transfer of heat within the Earth's interior, it is not the main method of transferring heat from the core to the crust. Radiation is particularly important in transferring heat from the Earth's core to the mantle, as the core's extremely high temperature causes it to emit thermal radiation. However, once the heat reaches the mantle, convection takes over as the primary mode of transfer.
Therefore, the correct answer is B. Convection.