What is the process by which heat moves through solids by touching one another?

The process by which heat moves through solids by direct contact is known as conduction. In conduction, when one part of a solid is heated, its particles begin to vibrate more rapidly and transfer their energy to adjacent, cooler particles through collisions. This transfer of energy continues through the material until the heat is evenly distributed.

Conduction is particularly effective in solids, where the particles are closely packed together. Metals, for example, are excellent conductors of heat due to their structure, allowing for efficient energy transfer. This physical phenomenon is essential to understand in building science as it affects how heat is managed within different materials in a structure, influencing energy efficiency and comfort levels.

In contrast, convection refers to heat transfer in fluids (liquids and gases) where heated portions rise and cooler portions descend, radiation involves the transfer of heat through electromagnetic waves without needing a medium, and thermal expansion refers to the increase in volume of materials as they heat up rather than a method of heat transfer.