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Post by silverdragon on Oct 8, 2014 9:41:21 GMT
This is something I "Learnt" as a child....
Glass slowly moves, it never truly sets.
Proof was measure old windows, they are thicker at the bottom than the top....
Therefore the glass is dropping slowly.
Cough.... erm.... ah... well... you see.....
Glass wasnt a perfect science back then, it was "Blown", they had no idea what float glass was, and glass was glass, and slightly imperfect.
The thicker end?.. well, logic stated that when installing glass you put the thickest end and probably the strongest part at the bottom to hold the weight of the rest of the pane.
Who started this stupid tale?... and why?.. glass is as solid as anything else inst it?.. up until the point it melts.
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Post by mrfatso on Oct 8, 2014 12:55:09 GMT
It is neither a liquid or a true solid, but another state of matter.
It is not considered a solid as it has no well defined crystalline structure to the atoms that make it up, and is not a liquid as the bonds in its atoms are not weak enough for it to behave as a liquid.
Now it is classed as an amorphous solid, which is what I think the modern agreement as to the terminology for it, however when I was at school it used to be refers to as a supercooled liquid, basically two terms meaning the same state of matter, with some slight differences between the definitions.
This is why many think of glass as a liquid, it was the phrase they remember from school.
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Post by the light works on Oct 8, 2014 13:53:32 GMT
It is neither a liquid or a true solid, but another state of matter. It is not considered a solid as it has no well defined crystalline structure to the atoms that make it up, and is not a liquid as the bonds in its atoms are not weak enough for it to behave as a liquid. Now it is classed as an amorphous solid, which is what I think the modern agreement as to the terminology for it, however when I was at school it used to be refers to as a supercooled liquid, basically two terms meaning the same state of matter, with some slight differences between the definitions. This is why many think of glass as a liquid, it was the phrase they remember from school. I was taught in school that glass moves over time. it was only fairly recently that someone with greater skepticism than most asked why glass that had fallen from antique windows and was laying balanced over something had not flexed; and researchers looked at other reasons why glass windows might be thicker at the bottom than at the top. don't know what original idiot floated the assumption that all glass was born perfect. |
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Post by watcher56 on Oct 8, 2014 15:34:49 GMT
Glass does not flow.
Example: Large telescopes have mirrors made from glass, with a thin aluminum coating. These mirrors are ground with extreme precision. If glass did in fact flow, these mirrors would become unusable in short order. That doesn't happen.
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Post by rick4070 on Oct 8, 2014 23:34:58 GMT
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Post by the light works on Oct 8, 2014 23:45:50 GMT
the last line is particularly good. |
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