Definition
The transfer of heat through a material, or from one material to another in direct contact, by the movement of energy between adjacent molecules without any bulk movement of the material itself.
Plain English
Heat moving through something solid, or from one thing to another that is touching it, without the material itself flowing.
Context Anchor
Seen in aviation weather when the ground warms or cools the air touching it, and in aircraft systems when heat moves through metal parts.
Derivation
From the Latin 'thermo' meaning heat, and 'conducere' meaning to lead or carry along. So 'thermal conduction' literally means heat being carried along — through the material itself, molecule to molecule.
Why Pilots Care
Many aircraft systems depend on conduction: cylinder fins shed combustion heat into the airflow, exhaust shrouds pass heat into the cabin heater, and overheated brakes can conduct heat into wheels and tires. Knowing how heat moves helps a pilot understand why cooling, shock cooling, and heat soak matter.
Analogy
If one end of a metal spoon is in hot soup, the handle can become warm even though it is not in the soup. Heat has traveled through the spoon by conduction.
Grounding Statement
Touch the metal handle of a hot frying pan and your hand gets burned — that is thermal conduction, heat traveling through the metal into your skin.
Intuition Check
Do not think of thermal conduction as heat carried by moving air or flowing liquid. In conduction, heat moves through direct contact; the material itself does not have to move from one place to another.
Example Sentence 1
Heat from the combustion chamber reaches the cylinder fins by thermal conduction, where the airflow then carries it away.
Example Sentence 2
Mechanics check for proper thermal conduction in the cylinder heads to prevent overheating.