how do I know if my windshield cracked from the inside or the outside?

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Clarification of Question by rabbitss-ga on 07 Nov 2005 19:43 PST

my husband said that a pipe he was loading into the car cracked the
windshield from the inside but that crack is rough on the outside not
the inside how do I know what really happened is this possible?

Well, you could ask your husband to find out what really happened, but
I assume he's still sticking to his story. If the area feels rough on
one side, I think it's safe to assume that it was hit from the
outside, not the inside, because when an object (whether sharp or not)
hits glass, it chips and cracks the side it hit. One would then use a
repair kit containing resin to fill in the cracks to prevent further
cracking.

My suggestion would be to press the question further to him, and point
out that he couldn't have possibly hit it from the inside, because
there is no evidence of an object scratching or colliding with the
glass. If he was lying before, he probably won't be able to explain
the physics of it. If he was telling the truth, he'll probably tell
you more in detail what happened, which, I believe, isn't likely to
happen. It's just not possible, unless it's a constant force that
pushes on the glass so as to bend it without cracking the side the
force hits, which isn't really the case with a pipe. Press him.

Good luck,

capndurk

An automobile windshield is comprised of two layers of glass with a
layer of plastic sandwiched in between the glass.  This laminate
process is designed to prevent the windshield from shattering upon
impact.

If the windshield is rough on the outside it is quite probable that
you husband is telling the truth. When an object passes through a
glass pain, such as a bullet, the shards of glass will typically be on
the opposite side. In your case if the pipe only knocked the window it
is quite possible for the glass to flex and crack on the outside.
However, without seeing the failure up close or by picture it is
difficult to say by email. We do a lot of accident investigation for
the police so if you really want to know check out www.bayworth.com