• Muehe@lemmy.ml
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      1 year ago

      Glass is actually more of a very slow moving liquid than a solid. You can see this on windows that are hundreds of years old, e.g. in churches. They will be thicker on the bottom because part of the glass flowed down.

        • Muehe@lemmy.ml
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          1 year ago

          It’s a matter of debate, but it definitely isn’t a solid.

          A more elaborate alternative definition is this: “Glass is a non-equilibrium, non-crystalline condensed state of matter that exhibits a glass transition. The structure of glasses is similar to that of their parent supercooled liquids (SCL), and they spontaneously relax toward the SCL state. Their ultimate fate, in the limit of infinite time, is to crystallize.” […]

          “On the other hand, any positive pressure or stress different from zero is sufficient for a glass to flow at any temperature,” he said. “The time it takes to deform depends mainly on temperature and chemical composition. If the temperature to which glass is submitted is close to zero Kelvin [absolute zero], it will take an infinitely long time to deform, but if it is heated, it will at once begin to flow.”

          • Calavera@lemm.ee
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            1 year ago

            You are telling me that if we heat glass it would deform? Who would have thought about that right

            • Muehe@lemmy.ml
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              1 year ago

              Heat in this context means any temperature above -273.15°C. Steel doesn’t display liquid properties at “room temperature”, glass does.

                • Muehe@lemmy.ml
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                  1 year ago

                  Deforming on time scales longer than a human life, so that’s why you wouldn’t see it. It might indeed be an urban legend, I don’t know, but given the claims in the article I cited I wouldn’t entirely discount the possibility.

          • botengang@feddit.de
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            1 year ago

            Their ultimate fate, in the limit of infinite time, is to crystallize.

            Alright, but the article is talking about long to infinite timescales. The discussion above was about church windows and that is not caused by glass flowing.

            • Muehe@lemmy.ml
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              1 year ago

              Their ultimate fate, in the limit of infinite time, is to crystallize.

              Alright, but the article is talking about long to infinite timescales.

              Long to infinite timescales for it to crystallise, that is to solidify. This is explicitly noted in the abstract of the paper the article is based on. I understood the “short timescales” on which it “relaxes towards the liquid state” to mean more than one human life time based on figure 4 (the image also shown in the article), but not so sure about the 10ky cited in the OP though.

              The discussion above was about church windows and that is not caused by glass flowing.

              Yeah that might indeed be an urban legend, could be manufacturing artefacts as claimed here. However I will note that the version of it I am familiar with isn’t about “bull’s eye marks, warps, and lines” as that article states, but specifically about old windows being thicker only at the bottom.