Well, everything was going great in the article until I got to this part in the first "Flowing Myth" example:
>At this rate, a piece of common soda-lime glass would take aeons to slowly flow and turn into the more energetically favourable crystalline sodium dioxide – otherwise known as quartz.
Quartz is not sodium dioxide - NaO2, it is silicon dioxide - SiO2. Sodium dioxide is probably not stable and after looking it up the most stable form is probably sodium peroxide - Na2O2. This guy forgot all about the sand he used to make the glass. The sodium part of the deal, sodium carbonate or soda ash - Na2CO3, was used to regulate temperature as he described and the lime was produced from local limestone, CaCO3.
This is a Physics World article and I would've expected someone to proof-read it specifically for stuff like this.
In reference to the Flowing Myth, I first heard that myth in a geoscience classroom and it was stated as a fact that old glass is thicker at the bottoms of cathedral windows because it has slowly flowed.
Taking that further, I guess it is a good thing that these cathedral windows were made of many panes of this old flowing glass since the thickening would not dramatically change the graphic display. If they were made of a single pane and it flowed significantly over time, Jesus may have started in medieval times as a finely cut specimen of manhood and ended up in modern times with a noticeable middle-age spread.
That is not all. It repeats the falsehood: The stability of glass is one of its most attractive characteristics, for example in the storage of nuclear waste.
Vitrified nuclear waste, immersed, would become porous and friable long before its radioactivity decayed significantly.
It also claims that we don't have proof glass doesn't flow in historical time-frames, where in fact we have glass goblets from thousands of years ago.
It further attributes tapering in glass in windows as indicating poor quality, where in fact that was just a feature of how flat glass was made. Window makers oriented glass thicker edge down because that was the sturdier way to make things.
Until quite recently, flat glass was made by blowing a big bottle, and centering it on a turntable while still soft. Spinning, the mouth widened until the whole thing flopped out flat, with a characteristic "whomp!", the bottle mouth becoming the rim.
> Vitrified nuclear waste, immersed, would become porous and friable long before its radioactivity decayed significantly.
Not quite. Silicates form a passive gel layer when put in water, they are quite resistant to leaching (we have examples of ancient Egyptian glass items recovered from the sea). Over very long time frames, way longer than millennia, the glass just dissolves. But for this you’d need them to be immersed and constant water circulation; silica is very stable. In this case you’re not worried about radionuclides release too much anyway, as the seas tend to be very large and have already quite a bit of them. Plus, only the low-activity isotopes remain isotopes after that time.
It depends on what you call “ordinary silicates”. The matrix is mostly sodium borosilicate with a bunch of additives and is as stable as a glass could be.
There are precipitates caused by some of the waste elements (things like ruthenium, rhodium and palladium, for example). They have issues but still quite far from making the glass crumble. As with all glasses, crystallisation is an open question but won’t happen for a very long time either.
>we have glass goblets from thousands of years ago
I think you'd also need to verify what it looked like thousands of years ago and whether it was stored in a way that held a consistent flow direction, if you wanted to use that as evidence.
I think you are a bit harsh on the author here. Sodium and silicon are very easy to mix up when writing, especially in an article where you talk about both quite often. It's also easy to overlook in proof reading because it sort of make sense in the sentence.
Regarding the flowing myth, I also heard the myth talking about cathedral glass planes being thicker at the bottom. There is a much more mundane reason for that though, it's much easier to handle a pane that is heavier at the bottom than the top, thus they were made that way. The myth is also debunked by the fact that there exist examples of cathedral glass panes which were made with the thick end up and haven't changed since then.
I wasn't trying to be harsh on the author. I thought about this late last night and decided that the easiest way to explain the error could be that the author was employed by Physics World to compose interesting articles in layman's terms and that the author does not have a technical background and those persons at Physics World who were supposed to proof-read this work dropped the ball.
In checking the byline you can see that the author is a freelancer and if you follow the link to their site you can see that they do a lot of technical writing for multiple publications on a variety of subjects. It is possible that they had a tight deadline for article submission, more articles to write, etc so that this one was dumped to the machine just in time for publication but without enough time for a good review that would've spotted this slight error.
> I guess it is a good thing that these cathedral windows were made of many panes of this old flowing glass
This is a myth. These are not “flowing glasses”. Silicate glasses have relaxation times in the billion years (the euphemistic “eons” in the article). There is no way medieval glass has had enough time to noticeably flow.
I'm actually a geophysicist and I understand that the glass doesn't flow. As I read the article and thought of the potential implications I was reminded of the old cartoon where the middle-aged man with a beer gut or paunch sees an attractive woman approaching so he stiffens his back, stands up straight and puffs out his chest as she passes so he can appear younger and more fit and virile. Once she has passed he lets gravity take control again.
I set up that scenario (or joke as has been noted by another reply) with the idea that detecting a middle-aged spread in an old window like that would be nearly impossible if the stained glass used to create the image, Jesus in this case, was constructed from a series of small pieces of glass constrained by a framework of lead caming as is used in stained glass construction. In this case, all the flow, if it occurred at all would be constrained at multiple points in the framework so that the image would remain nearly identical over the aeons as long as the framework existed in good condition.
However, if glass did indeed flow and if that flow was detectable over the few hundred years that have passed since those cathedrals were constructed and also if each window was made from a single sheet of this glass with an image painted on the glass - then the image itself could be expected to exhibit noticeable changes over significant time periods and it would naturally follow that young Jesus would eventually become middle-aged Jesus with a paunch, like the guy in the cartoon.
It was late at the time and my mind was wandering again, punching at the lines while trying to leak some color to the outside.
>At this rate, a piece of common soda-lime glass would take aeons to slowly flow and turn into the more energetically favourable crystalline sodium dioxide – otherwise known as quartz.
Quartz is not sodium dioxide - NaO2, it is silicon dioxide - SiO2. Sodium dioxide is probably not stable and after looking it up the most stable form is probably sodium peroxide - Na2O2. This guy forgot all about the sand he used to make the glass. The sodium part of the deal, sodium carbonate or soda ash - Na2CO3, was used to regulate temperature as he described and the lime was produced from local limestone, CaCO3.
This is a Physics World article and I would've expected someone to proof-read it specifically for stuff like this.
In reference to the Flowing Myth, I first heard that myth in a geoscience classroom and it was stated as a fact that old glass is thicker at the bottoms of cathedral windows because it has slowly flowed.
Taking that further, I guess it is a good thing that these cathedral windows were made of many panes of this old flowing glass since the thickening would not dramatically change the graphic display. If they were made of a single pane and it flowed significantly over time, Jesus may have started in medieval times as a finely cut specimen of manhood and ended up in modern times with a noticeable middle-age spread.