A riddle for you all (smart arses in physics, tune in)

[Klint]

alright,

Today I've been busy moving audio equipment from home to home, the reason being that to find the best audio solution - the set up is a constant evolution (Ala F1 car)

anyway, we got a four shelf stand, that houses four glass pieces, about 5/6th of an itch thick that holds the audio equipment on top, so these are pretty heavy duty pieces of glass. These pieces of glass slide into the metal frame to produce the stand.

Well, we took the glass pieces out of the frame to transport the shelf. Coming off the mountain road the top piece of glass shattered without any noticable (or no) damage to the other three pieces that were underneath the fourth piece. So, we were coming down to sea level from about 1600feet, this wasn't sudden. since the four pieces didnt make contact with anything else other than the other pieces of glass, it's got me wondering what affects physics and the law of gravity had on the fourth piece to shatter itself without any accord.

I'll be interested in each and every theory as to why the top piece of glass shattered without making contact with anything other than the third piece of glass that was underneath it?

[sturs6]

Was it like this rack?

[Snow]

1600 ft ain't much.
I doubt mother nature had something to do with it. It could have been plain and simple bad luck with some sort of stress focused on the top glass shelf.

I'll take out my form-collection and calculate on the difference in air pressure.

[Snow]

Since the air pressure decreases with 1 hPa every 8 meters (1 meter is roughly 3 ft.) the difference in pressure between point a and point b (assuming point a lies 1600ft. higher than point b) is about 66 hPa.

I think you are more familiar with Bar, and for you, I can tell that 1 hPa is equal to 1 millibar.

What I'm trying to say is that, as I said before, I don't think that the air pressure (or the gravity) has anything to do with it.
Probably just bad luck. Next time, be sure to put a towel or something in between.

[Klint]

Stuart,

It's similar to that stand.

Snow,

Thanks for the information.

Why I thought it was pressure was because the thing literally exploded in the back seat!! There was glass everywhere. Lucky it didn't hit the front seat occupants (one being me) when it did go.

If it isn't pressure related then what caused it?

Friction between the glass plates? Static electricity? Nannobots?

[Snow]

Well, I think that the direct cause is resonans, and that itself is caused by friction between the glass plates.
But don't quote me, I'm just guessing! :trash:

[bilbozilla]

I'm assuming it was tempered glass?

[Klint]

Originally posted by bilbozilla
I'm assuming it was tempered glass?

I'm not too sure what you mean by tempered glass? Feel free to elaborate. I know the glass was in a spectacular condition by looking at it with the naked eye.

This is the exact frame that we were transporting. I'm not sure what type of glass is used?

[Erik]

Probably a lot of tension in the glass.