What is defined as the observable changes in materials as a result of fire?

The term defined as the observable changes in materials as a result of fire is "Fire Effects." This concept encompasses the various physical and chemical transformations that materials undergo when exposed to heat and flame, including char formation, discoloration, distortion, melting, and other changes in physical properties. Understanding fire effects is critical for investigators as it helps in assessing the intensity and duration of the fire, which can provide insights into the fire's origin and spread.

In contrast, fire patterns refer specifically to the visible marks or residues left on surfaces that indicate the movement and behavior of fire. Fire spread deals with how fire advances through different materials or structures, while fire science encompasses the broader study of fire, including its chemistry, behavior, and effects, making it less specific to the observable changes caused by fire. Thus, "Fire Effects" is the most accurate and focused term for describing the observable changes in materials due to fire.