How to Determine if a Glass was Broken from Inside or Outside

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In summary, the episode of CSI discussed a broken window at a crime scene and how forensics determined that it was broken from the inside, indicating a possible burglary. The method used was analyzing the fracture patterns and looking for Haeckel marks, which are not recognized as a reliable indicator. The question of whether glass is a liquid or solid is still debated, with some considering it an amorphous solid and others a highly viscous liquid. However, it is generally classified as a solid for practical purposes. The belief that old stained-glass windows appear to "run" due to glass being a liquid is false, as it is actually thicker at the bottom due to the manufacturing process.
  • #1
vabamyyr
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I saw CSI today and a glass was broken on the crime scene and furensics took one sample fracture from there and did one experiment in the laboratory also. (experimentor broke a window (glass) with baseball bat). And then they analysed those 2 fractures(one from scene and one from lab) and determined that the glass broken on the crime scene was done from the inside not from outside which would refer to burglary. But i couldn't figure out how. They talked about some Haeckel marks? and i typed it into google search and found nothing. Anyway can someone tell me the method determing whether normal window (glass) is broken from inside or outside, or is my question too confusing?
 
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  • #2
http://www.stanford.edu/~zhongj/SGKBweb/def/joiSurMor.html [Broken]

http://members.aol.com/JRD203/csi-episode-010.htm [Broken]

Enjoy.
 
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  • #3
i also have a question about glass: is it a liquid or a solid?

because i read something that claimed it is now considered a liquid with high viscosity, since old stain-glass windows appear to "run".
 
  • #4
The thing about glass flowing in churches is untrue. The reason that such glass is thicker at the bottom is due to the manufacturing process. This glass was generally blown, flattened, and then spun, meaning that the glass was thicker on the outside of these big discs. The glass was then cut up into sheets, and when installed, common sense led to the glass being installed with the thick (heavy!) side at the bottom.


The answer to the question "is glass liquid or solid" is not a clear one, and if you use the search facility you will see some rather long debates presenting both sides of the argument. For engineering purposes, I like to class glass as an amorphous solid, although there are arguments for it being a highly viscous liquid, and some class a "glass" as being a separate category altogether.
 
  • #5
brewnog, thanks for the clarification.

i can remember when there were just 3 forms of matter, solid/liquid/gas..those days are long gone. :smile:
 
  • #6
quetzalcoatl9 said:
brewnog, thanks for the clarification.

i can remember when there were just 3 forms of matter, solid/liquid/gas..those days are long gone. :smile:


For most practical purposes, it's still prudent to make a distinction between those three states. I'd always treat glass as a "solid" (unless it were molten :smike:)
 

1. How do I visually determine if a glass was broken from the inside or outside?

The easiest way to determine this is by examining the pattern of the breakage. If the glass is broken from the outside, the cracks will radiate outward from the point of impact. If the glass was broken from the inside, the cracks will radiate inward from the point of impact.

2. What if the glass is shattered into many small pieces?

In cases where the glass is broken into small pieces, it may be more difficult to determine if it was broken from the inside or outside. However, you can still look for clues such as the direction of the cracks or the presence of any debris on one side of the glass.

3. Can I use a magnifying glass to determine the direction of the cracks?

Yes, a magnifying glass can be helpful in determining the direction of the cracks. It can also help you identify any small debris that may be stuck to one side of the glass, indicating the direction of the impact.

4. Is there any other method to determine the cause of the break?

In addition to examining the pattern of the breakage, you can also try to gather more information about the circumstances surrounding the break. For example, if the glass was broken in a location with no external force, it is more likely that it was broken from the inside.

5. Why is it important to determine if the glass was broken from the inside or outside?

Determining the cause of the break can help you understand the potential risks associated with the type of glass used. For example, if the glass was broken from the inside, it may indicate a structural weakness that could lead to further breakage. It is also important for insurance purposes and to prevent any potential accidents in the future.

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