Thermal Properties

There are five categories of energy stimuli that every material must respond to: mechanical, thermal, electrical, chemical and optical. Beyond these five categories are many less important ones, and a more comprehensive list of material properties can be found here. An input of one or more of these energies will produce a change in the material’s composition or microstructure.

In general, thermal properties are related to conductivity of a material - which is based upon the freedom that valence electrons have to move. There are many subcategories of thermal properties which will are detailed in this discussion.

The most common thermal property defined is thermal conductivity. Heat “goes” to cold, and how well a material prevents or allows this change is its conductivity. A material that is a good conductor, such as metals, allows heat transfer easily, while other materials such as wood or ceramics are not as efficient. Most of the reasons for a material’s conductivity are directly related to the movement of electrons; if the material has a high level of electron movement, energy can be transferred at different rates from atom to atom. A more in depth look at thermal conductivity can be found here.

Thermal image of wooden siding in a room showing its heat in degrees - in some settings, such as buildings, a material which retains heat is more beneficial because of lower conductivity.

A thermal property that many materials will experience is thermal expansion, where a raise in temperature causes the material to increase in volume (taking up more space). Most materials have a certain temperature threshold, causing the opposite, negative thermal expansion, to occur.

Specific Heat

Flammability

Melting Point

Boiling Point