What type of glass fractures form first?
What type of glass fractures form first?
(a) Radial cracks are formed first, commencing on the side of the glass opposite to the destructive force. (b) Concentric cracks occur afterward, starting on the same side as the force. FIGURE 4-19 Stress marks on the edge of a radial glass fracture.
What is a concentric fracture in glass?
Concentric cracks are fractures forming in an approximately circular pattern around the point of impact. They are usually in straight segments that terminate in an existing radial crack.
When a bullet penetrates a panel of glass it leaves a crater shaped hole that?
Terms in this set (24) When a bullet penetrates a panel of glass, it leaves a crater-shaped hole that: is wider on the exit side an forms randomly and hence the direction of impact cannot be determined but its appearance.
How does the speed of impact affect the number of concentric fractures formed in the glass?
What can we tell about speed from a glass with fewer concentric fractures? Objects at higher speeds cause fewer concentric fractures than objects at lower speeds.
What are two characteristics used to identify glass?
Refractive index n = 1.52 The measure of deflection determines the refractive index. For float glass, this refractive index is n=1.52. The main characteristics of glass are transparency, heat resistance, pressure and breakage resistance and chemical resistance.
What techniques do you use to identify glass?
The flotation and immersion methods are best used to determine a glass fragment’s density and refractive index, respectively. The latter involves immersing a glass particle in a liquid medium whose refractive index is verified unit it is equal to that of glass particle.
What is the most common type of glass?
Soda-lime glass
In what way can glass be considered individual evidence?
Glass can be found as individual characteristic in cases where significant fitting of two glass fragments. It is class evidence most of the time because without two fitting glass fragments, the glass can be identified but not linked to a specific object.
What is the primary ingredient of glass?
silica