In fire investigations, how can glass be affected by heat and flame?

In fire investigations, glass is affected by heat and flame in specific ways that provide valuable information about the fire's behavior and intensity. When glass is subjected to high temperatures, it can experience thermal stress, which often leads to cracking. This phenomenon occurs because glass is a poor conductor of heat, causing parts of the glass to heat up and expand at different rates. As a result, this uneven expansion creates stress within the material, leading to cracks.

Additionally, crazing may occur, which involves the formation of tiny surface cracks that can appear as a network of fissures. These effects are important for investigators, as they can indicate the fire's temperature and duration, helping to reconstruct the sequence of events during the fire incident.

Understanding these characteristics of glass in relation to fire can aid in determining the origin and cause of the fire, making it a crucial aspect of fire investigations. The other choices do not accurately reflect the typical behavior of glass under high temperatures in a fire scenario. For instance, glass does not remain intact in the presence of significant heat, and while it can melt in extreme conditions, complete melting is not the norm in most fire incidents. Burn patterns may also be observed, but they are not exclusively related to the inherent characteristics of glass