How can you determine which holes or fractures occured before others on a piece of glass?

Question

If you shot a panel of glass three times, how do you know which hole created was the first one? (assuming the glass is safety glass)

Answer 1

Examine the crack lines. Crack lines radiating from the first hole will be continuous and uninterrupted. Crack lines radiating from the second hole will stop abruptly when they meet a crack caused by the first shot. And of course crack lines radiating from the third hole will stop when they meet a crack from either the first or second shot.

Answer 2

The first answerer is close.

Glass is actually a liquid and not a solid. If you want to see the difference and they occured over the course of several years you would look for shifting in the holes or fractures (microscopically). They may not be more worn but you will see where they have slipped past the original edge.

If glass is left alone for a hundred years or more you will find that it is much thicker at the bottom than at the top.

Answer 3

i would say probably look closely to see how fresh the jagged edges are the older one would probably have worn a little more for moving it around and such good luck may i ask what this is for