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How does thermal conduction transfer heat through a solid?

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heating In a thermoelectric generating system a heat source—usually fueled by coal, oil, or gas—is used within a boiler to convert water to high-pressure steam. The steam expands and turns the blades of a turbine, which turns the armature of a generator, producing electric power. A condenser converts any remaining steam to water, and a pump returns the water to the boiler.

In a solid, thermal conduction transfers heat through molecular or atomic agitation and contact between particles, rather than through the physical movement of the material itself.1

Heat moves along a temperature gradient—from an area of higher temperature and greater particle agitation to an area of lower temperature and less agitation. This process continues until the material reaches thermal equilibrium, where the temperature is uniform throughout. The rate of this transfer depends on the material's thermal characteristics, such as its atomic composition and the distance the heat must travel.1

In many solids, this energy transfer is facilitated by phonons, which are discrete units of vibrational energy arising from oscillating atoms within a crystal lattice. In metals, thermal conductivity is also significantly influenced by the migration of free electrons, which move as a group throughout the solid to convey energy.234