diathermancy

Diathermancy refers to the property of a substance to allow heat to pass through it. This is essentially the opposite of thermal insulation. A substance that is highly diathermanous permits a significant amount of heat to be transferred through it, while a substance with low diathermancy resists the passage of heat. This phenomenon is primarily related to the conduction of heat within a material.

Different materials exhibit varying degrees of diathermancy. Metals, for example, are generally very diathermanous due to their free electrons, which can efficiently transfer thermal energy. Conversely, materials like wood, plastic, or air are poor conductors of heat and therefore have low diathermancy; they are considered good thermal insulators.

The concept of diathermancy is important in various fields, including thermodynamics, materials science, and engineering. For instance, in the design of buildings, materials with low diathermancy are used for walls and roofs to retain heat in winter and keep it out in summer. In industrial processes, understanding the diathermancy of equipment components is crucial for efficient heat management and preventing heat loss or unwanted heat gain. The term itself is derived from Greek words meaning "heat" and "through."