Final answer:
Glass fracture lines that encircle the point of impact are known as radial fractures. These are a type of breakage that extends outward from the source of impact, providing insight into the direction and order of impacts on glass.
Step-by-step explanation:
The glass fracture lines that encircle the hole in the glass are known as radial fractures. When glass experiences enough energy, such as a blunt force, it vibrates until it shatters. These fracture lines can be observed in the pattern they form, encircling the point of impact like a spiderweb. It should not be confused with cleavage, which refers to minerals breaking along planes with weak chemical bonds. Instead, glass fracture is an irregular breakage. In geology, examining the characteristics of fractures, including those in glass, can provide insights into the material's properties and the conditions it has been subjected to.
Radial fractures often originate at the point of impact and extend outwards. This directional pattern is generally visible and can sometimes assist investigators in determining the order of impacts when multiple fractures are present. Understanding the nature of glass fractures is vital in fields ranging from forensic science to materials engineering.