Heat transfer

Definition

Heat transfer is the process of thermal energy moving from a region of higher temperature to a region of lower temperature. It occurs through conduction, convection, and radiation.

5 Must Know Facts For Your Next Test

1. Conduction is the transfer of heat through a solid material by direct contact.
2. Convection involves the movement of heat by the physical motion of fluid (liquid or gas).
3. Radiation is the transfer of heat in the form of electromagnetic waves, such as infrared radiation.
4. The rate of heat transfer can be described mathematically using Fourier's law for conduction: $q = -kA \frac{dT}{dx}$.
5. Thermal equilibrium occurs when two objects in thermal contact no longer exchange heat, meaning they are at the same temperature.

Review Questions

• What are the three primary mechanisms of heat transfer?
• How does conduction differ from convection?
• Explain how radiation can transfer heat without direct contact between objects.

Related terms

Thermal Conductivity:

A measure of a material's ability to conduct heat, denoted by $k$.

Specific Heat Capacity: The amount of heat required to raise the temperature of one kilogram of a substance by one degree Celsius.

Stefan-Boltzmann Law:

$P = \sigma A T^4$: A law stating that the power radiated per unit area by a blackbody is proportional to the fourth power of its absolute temperature.