In fire investigations, which characteristic of glass helps identify the fire's intensity?

The characteristic of glass that helps identify the fire's intensity is the cracking patterns. When glass is exposed to high temperatures, it can exhibit various forms of cracking depending on the heat intensity and duration. These patterns can provide significant clues about the temperature to which the glass was subjected, as well as the nature of the fire itself. For instance, certain types of cracking might indicate that the glass experienced rapid heating and cooling, while others might suggest prolonged exposure to heat. The specific patterns can also reveal information about the rate of temperature increase, ultimately helping investigators assess the intensity of the fire.

Other characteristics such as thickness, color, or size of the glass object do not consistently provide the same level of insight into the fire's conditions as cracking patterns do. Thickness may influence melting points but doesn’t effectively indicate intensity alone. Color can be a byproduct of the glass’s composition rather than fire effects, and size does not inherently relate to the thermal history of the glass. Therefore, cracking patterns serve as the most direct and informative characteristic in relation to assessing fire intensity.