Question

After a house fire, your partner collected these two pieces of glass and placed them into evidence. She noted that sample A was taken from the bedroom window and was likely caused by a break-in. She also noted that sample B was taken from the living room and the breakage was likely caused by heat. Support or defend her analysis and state your reasons.

Answer 1

When glass breaks, it can leave distinctive patterns or features that can be used to determine the cause of the breakage. For example, glass that has been broken due to a break-in will often have a pattern of radial cracks emanating from a point of impact, such as a hammer strike or bullet hole. On the other hand, glass that has been broken due to heat stress will often have a pattern of parallel cracks or a "spiderweb" pattern that radiates from a central point.

In addition to the pattern of cracks, the location of the glass can also provide clues about the cause of breakage. Glass that has been broken due to a break-in will often be located near a point of entry, such as a broken window or door. Glass that has been broken due to heat stress may be located near a heat source, such as a fireplace or stove.

Based on these general principles, your partner's analysis may be plausible. If sample A was taken from a bedroom window and has a pattern of radial cracks emanating from a point of impact, it is possible that the glass was broken due to a break-in. If sample B was taken from the living room and has a pattern of parallel cracks or a "spiderweb" pattern that radiates from a central point, it is possible that the glass was broken due to heat stress.

Answer 2

Support her analysis: sample A's glass looks fractured and split likely from physical external force applied to the glass. Sample B's glass looks like it make have bubbling and splitting internally which may come from an increase in temperature.