Unsolved Mystery - What Caused the Broken Window?

[Borek]

So, yesterday I was alone at home standing in the kitchen reading a paper when I heard a loud, sharp sound, as if something felt on the floor. I checked all rooms and attic looking for what it could be, but there wasn't anything. We don't have animals, neither our own or visiting, so I could not find an explanation.

Accidentally today I was looking for something in a carton boxes that are in the corner of our attic and I realized floor shines as if it was covered with tiny pieces of glass. I looked up and...

Only internal pane is broken, glass on the outside is intact. Initially all glass was in place, but as some pieces were relocated I took them out, as I was afraid they could fall and make holes in floor panels.

This is (or rather was) a sealed double pane glass window, that was placed here in 2002, so it survived almost 9 years. Temperatures on Friday were typical for this part of the year and in no way more stressing than usual. This is a northern slope of the roof, so it is not getting very hot in the Sun. I guess it was some combination of stress and fatigue that resulted in the crack. Still... X-Files.

 

[Evo]

Ooh, you can get that whacko from Ghost Adventures to lock himslef in your home overnight and take infrared pictures of himself.

Seriously, that is very strange. Has Wolram visited you?

 

[nismaratwork]

Hmmm... has it been especially cold? The temperature gradient could do that, between the outer and inner pane, esecially in a wood frame.

edit: think "twisting"

edit2: If you have kids, that's always a culprit too

 

[rhody]

Hmmm, let me see telescope = kid magnet, kids with toys, kids play with telescope, kids get bored and start bouncing a superball, even a small one. Bingo... Kids and ball disappear, Ghost story, urban legend begins... possible ?

Rhody...

 

[rhody]

Hmmm... has it been especially cold? The temperature gradient could do that, between the outer and inner pane, esecially in a wood frame.

edit: think "twisting"

edit2: If you have kids, that's always a culprit too

Holy crap nismara, you hadn't posted when I started and I went back to look, double bingo... you beat me to it, I just laid out a possible scenario, that's weird my friend...

Rhody... maybe this thread is haunted...

 

[lisab]

Hmmm... has it been especially cold? The temperature gradient could do that, between the outer and inner pane, esecially in a wood frame.

edit: think "twisting"

edit2: If you have kids, that's always a culprit too

Wood can expand and contract as its moisture content changes, too.

 

[Borek]

No kids, no visitors, no serious temperature gradients. Just me and the paper in the other room on different level.

 

[nismaratwork]

Wood can expand and contract as its moisture content changes, too.

Oooh, good point.

@Rhody: I'm fast, but accuracy suffers as a result.

 

[nismaratwork]

No kids, no visitors, no serious temperature gradients. Just me and the paper in the other room on different level.

Lisa may be right then... heat rises, dry's the wooden interior, and if it's been especially humid... CRACK.

edit: Glass does "just break" too... I note that's pane glass, and not safety glass, so over time the "melting" effect can emphasize defects in one pane.

 

[Borek]

Wood can expand and contract as its moisture content changes, too.

Actually that could be a reason. I have a problem with varnish on these windows. I did my best to clean old cracked layer and to paint the wood before the winter, but for sure wood is not protected as well as it originally was.

We are thinking about replacing windows with a plastic ones, these should be better suited to the condensation level. No idea what is going on, there is no high humidity in the house, but attic windows are often wet from the inside. And these are not some "noname" windows, Velux is a reasonably good brand.

 

[rhody]

Another thought occurred, the telescope if not lifted carefully could easily do that kind of damage. I am guessing that heat stress would not occur with equal force from all four sides, I would expect to see corner stress not as evenly distributed from all four sides as in the picture, suggesting puncture failure. Borek, check the end of the telescope carefully looking for scratches.

Rhody...

 

[Borek]

There was no one to lift the telescope - unless it IS a ghost story. I will examine the glass tomorrow in more details, corner is too dark now.

 

[nismaratwork]

If the telescope had been lifted, the bottom of the window should have been swept out first... no, lisab is probably right.

Borek: That sounds like a good idea... I assume you open the window to stargaze, right?

 

[Borek]

Borek: That sounds like a good idea... I assume you open the window to stargaze, right?

No, I haven't use it in years. It was a gift for Junior when he was about 10, now it is mostly collecting dust. We live too close to the large city (dust & light pollution) for any reasonable stargazing. When Junior was going with us on vacation we were taking the telescope with us, but as far as I remember last time he was with us on regular vacations was in 1999...

 

[nismaratwork]

No, I haven't use it in years. It was a gift for Junior when he was about 10, now it is mostly collecting dust. We live too close to the large city (dust & light pollution) for any reasonable stargazing. When Junior was going with us on vacation we were taking the telescope with us, but as far as I remember last time he was with us on regular vacations was in 1999...

Definitely no reason to stick with glass then... just seal it off with what you were talking about.

 

[Proton Soup]

so it was DHMO poisoning?

 

[caffenta]

Maybe a bird quantum-tunneled through the outer pane, hit and broke the inner pane, became unconscious, fell to the floor, and then disintegrated somehow?

On a more serious note, you might have a bird inside your house that tried to get out and broke the glass, then hit the floor and flew away before you got there. I would have suggested a bat also, but a bat would be able to notice that there is glass blocking the way, although they can do strange things when they come out of hibernation.

Other than that, I would go for wood expanding/contracting like others have said.

 

[lisab]

Maybe a bird quantum-tunneled through the outer pane, hit and broke the inner pane, became unconscious, fell to the floor, and then disintegrated somehow?

On a more serious note, you might have a bird inside your house that tried to get out and broke the glass, then hit the floor and flew away before you got there. I would have suggested a bat also, but a bat would be able to notice that there is glass blocking the way, although they can do strange things when they come out of hibernation.

Other than that, I would go for wood expanding/contracting like others have said.

Or a bat.

 

[caffenta]

Or a bat.

Ahem...

I would have suggested a bat also, but a bat would be able to notice that there is glass blocking the way, although they can do strange things when they come out of hibernation.

 

[lisab]

Ahem...

Lol...I should read more carefully !

 

[rhody]

Maybe a bird quantum-tunneled through the outer pane,

caffenta,

That is great, a comment like that could only fly (pun intended) on a forum like ours with a (for the most part) physics background. On any other forum, people would be googling the term to figure out what you meant.

Rhody...

 

[waht]

Perhaps the glass has been broken for years and it was something else that fell and made the noise.

 

[nismaratwork]

Hmmm... what's the quantum of bird? Tweetion. Wait.. this isn't he Lame Jokes thread... heh... sorry!

 

[Dembadon]

I'm throwin' in with the quantum tunneling, flying animal -- much more exciting than the expansion of wood.

 

[Ivan Seeking]

I've heard that defects in the tempering process can result in spontaneous breakage much later; esp if there are addtional stresses due to swelling of the frame and the like.

Spontaneous glass breakage is a phenomenon by which toughened glass (or tempered) may spontaneously break without any apparent reason. The most common causes are:

Minor damage during installation such as nicked or chipped edges which later develop into larger breaks
Binding of the glass in the frame causing stresses to develop as the glass expands and contracts due to thermal changes or deflects due to wind
Internal defects within the glass such as nickel sulfide inclusion.
Thermal stresses in the glass
Inadequate glass thickness to resist wind load

http://en.wikipedia.org/wiki/Spontaneous_glass_breakage

 

[Dembadon]

I've heard that defects in the tempering process can result in spontaneous breakage much later; esp if there are addtional stresses due to swelling of the frame and the like.http://en.wikipedia.org/wiki/Spontaneous_glass_breakage

That glass (Borek's) isn't tempered, though. It's annealed. Tempered glass doesn't "run-out" like that, it shatters into a million little pieces.

 

[lisab]

That glass (Borek's) isn't tempered, though. It's annealed. Tempered glass doesn't run like that, it shatters into a million little pieces.

It sounded to me like that glass had a pretty bad temper.

 

[Dembadon]

It sounded to me like that glass had a pretty bad temper.

You're dang clever, lisa. I worked at my dad's glass shop for 8 years and could've used that so many times.

 

[Ivan Seeking]

That glass (Borek's) isn't tempered, though. It's annealed. Tempered glass doesn't "run-out" like that, it shatters into a million little pieces.

I thought all glass used for homes had to be tempered [in the US anyway].

Also, assuming it is annealed, couldn't other defects still cause the annealing process to fail; resulting in unwanted internal stresses?

 

[Dembadon]

I thought all glass used for homes had to be tempered [in the US anyway].

Not all; just glass in stairwells; in the ceiling; in doors; in openings that are a certain distance from a door or a certain height off the ground; in shower doors; and a few I've probably forgotten.

I'm not sure about Poland, though.

In the U.S. it is common to see older homes (1970's and prior) that have annealed glass where tempered glass should be, but this is because the laws were different back then. Nowadays, your home won't pass inspection if you aren't up to code. And, as a glass company, you are required to meet code, even if you're installing glass in an older home that wasn't up to code when you accepted the job.

 

[Dembadon]

[...]

Also, assuming it is annealed, couldn't other defects still cause the annealing process to fail; resulting in unwanted internal stresses?

That's a good question. I'm not sure, but I've never had a piece of glass that was stamped tempered turn out to be annealed. I think that would be a major liability for the manufacturer. My dad might know, he was a glazer for approximately 35 years. I'll ask him if I remember the next time I talk to him.

 

[Newai]

Just to be safe, pour baking flour all over the floor and paint big red Xs all over the walls. You might also want to cover the floor with tacs and potato chips and syrup.

Ghosts hate that stuff.

 

[nismaratwork]

Just to be safe, pour baking flour all over the floor and paint big red Xs all over the walls. You might also want to cover the floor with tacs and potato chips and syrup.

Ghosts hate that stuff.

On the other hand, it sounds like fun for small animals, or some kind of fetish-wrestling.

 

[Borek]

Just to be safe, pour baking flour all over the floor and paint big red Xs all over the walls. You might also want to cover the floor with tacs and potato chips and syrup.

Convince Marzena to do so.

 

[rhody]

So Borek,

Did the suspect telescope have anything to do with the broken glass ?

Rhody...