it was found that windows taken from very old buildings show difference in thickness.. The window glass is thinner at top and thicker at the bottom...look at the figure.
http://mywebpages.comcast.net/billotto/Image020_glassflow.gif


so let's tease and squeeze our minds t find the reason behind this. Not only that, let's argue with the answer..

could it be that after a 100 years the glass somehow begins losing its support and thus it balances itself? that seems impossible since it isn't a living thing... could perhaps years of enduring weather changes cause it to "melt"?

good... so why the bottom becomes thicker

Gravity would have to do something with why the bottom part is thicker.

emmm yeap dede... so you are saying the glass is like a liquid not a solid so its component moves with time due to gravity...??

I've come across this before, and I think it was one of our teachers that once told us about this phenomenon.

It's mainly due to two reasons (I think), one being the Earths gravitational force over a prolonged period of time and the other being the nature of glass. I think glass' molecular structure categorises it as a ceramic, however it acts differently because it is one with a very high viscosity which is possibly immeasurable.

*scratches head* :think:

Maybe I should stop there before I drive somebody nuts :D

^ wise. was going to go nuts :p

emmm yeap dede... so you are saying the glass is like a liquid not a solid so its component moves with time due to gravity...??

The structure is like that of a liquid but it doesnt act like one.. I mean the molecules don't move around, they're strongly bounded to eachother unlike liquids.
So I cant think of why it becomes thicker at the bottom over time!
Looking forward to the answer!

The UV Rays?

UV Rays = Ultraviolet Rays... !

I forgot to add that what I meant by high viscosity is a highly viscous liquid.

i wanna answer and argue at the same time... tomorrow i will put my input...

sorry for being late for this thread,

yeap most of you got it right... some or majority of scientist classify glass as kind of liquid or a gel but not solid. It does show by studies that it has some micro-flow due to the special arrangement of glass crystals. This kind of movement or flow depends on the way the glass is made and kind of material is being mixed with it.


thus due to gravity and time factor, most of glass contents moves down making it more thicket at the bottom. Some scientist argued about this claiming that this thing occur due the the chamber which the glass has solidified while making it. In Older time, the chambers used to be thicker at the bottom..

Other argues about this by looking at very old lens taken from old microscopes or telescopes... they are still accurate and if the glass contents have moved due to its liquid nature the accuracy of these lenses would have been distorted.

thus there is no 100% answer to why old glasses are thicker at the bottom... don't believe teachers in schools. School books support the fir4st theory that glass is a liquid.

^ Interesting..
I knew it had something to do with the Gravitational Force :D

^ same here!

really interesting FaHaD ;)

Thanks for your valuable input FaHaD :)

Other argues about this by looking at very old lens taken from old microscopes or telescopes... they are still accurate and if the glass contents have moved due to its liquid nature the accuracy of these lenses would have been distorted.

Now this is something that got me thinking :think:

Aiwaa laa...

me too?????

Thanks for the info Fahad :cute:
Yeah I guess it's still arguable..
but i've read so many places that glass being a liquid is just an urban legend. People noticed in old buildings that the glasses are thicker at the bottom, but there are other even older structures like the ones in Egyptian tombs that haven't changed shape. If it were true, they would've turned into puddles! :p

I'll try to find more sources :cute: