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Glass viscosity calculations debunk the myth of flow in medieval windows (2017)

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Re: Glass viscosity calculations debunk the myth of flow in medieval windows (2017)

#121

Post by inetknght »

onion2k wrote: post #98
nikisweeting wrote: post #2

Finally! I always knew my 7th grade science teacher was full of shit on that one, she was so adamant about some things that turned out to be wrong. This one was maybe more excusable because it was common to teach at the time. Maybe it ended up making us better students in the end because we learned to fact-check our teachers, and not to be adamant about things we only think are true (though I'm still guilty of that m…

The problem is that it's obviously wrong with a simple experiment - just look at a few really old windows. I live about 1/4 mile from a church that was built 1300 years ago ( https://en.wikipedia.org/wiki/St_Peter%27s_Church,_Monkwearm... ). There's not much of the original glass left but where there is the thicker part is occasionally at the top of the pane because that's how it was originally mounted. Teachers (and…

> Teachers (and everyone else) will be wrong about things. That's OK. The problems happen when people don't bother to do any simple checks themselves, and just accept things as fact without doing any critical thinking or experimentation of their own.

While not doing checks against teachers is a problem... there is a bigger problem of teachers who don't accept being wrong.

Re: Glass viscosity calculations debunk the myth of flow in medieval windows (2017)

#122

Post by michaelt »

nemo44x wrote: post #117
_fi0w wrote: post #92

Earlier quoted context omitted.

My parents, both with master’s degrees, worked at least eight hours every day teaching, grading assignments, and then preparing for the following day. I would guess about ten hours on average, seeing as I was mostly left alone as a child while my parents worked over the kitchen table. Yes, they don’t teach during the summer. Their pay reflects that. I won’t even touch on personal expenditures for supplies. Grifters?!…

> ...shape society’s future while fighting its current failures. All while being inexplicably hated and ridiculed by students, parents, and I guess HN. I’m not sure how to interpret this. Are you saying they indoctrinate kids? Do they exist to teach kids __how__ to think or __what__ to think? Which current failures are they fighting? As to my previous comment about “grifters”, I’ll admit that was too cynical and over…

> Which current failures are they fighting?

Depending on the teacher and school, everything from kids coming to school hungry or without supplies to obesity to discipline problems to cheating to bullying/cyberbullying to child abuse to uninvolved parents to mental health problems to anxiety to drugs to deficiencies in the curriculum to achievement gaps between genders, classes and races to lack of good role models to gang culture.

That's not to say every teacher works to address all those things at once - at some schools they might not contend with any at all! But I've seen people call on the education system to do almost everything you'd otherwise expect parents to do.

Re: Glass viscosity calculations debunk the myth of flow in medieval windows (2017)

#123

Post by chabad360 »

4ad wrote: post #96
ternaryoperator wrote: post #71

>Their measurements reveal that medieval glass has a much lower viscosity than expected at room temperature—16 orders of magnitude less than previous estimates It's pretty rare to read an article in which the degree of previous error is sixteen orders of magnitude.

The way viscosity is measured doesn't follow naive expectation though. Water at 0C has over six times the viscosity of water at 100C, yet to the untrained human they seen to flow about the same. Olive oil is 100 times more viscous that water. Yoghurt about 10000 times more viscous than water.

Fair, but keep in mind that it's orders of magnitude we're taking about.

Re: Glass viscosity calculations debunk the myth of flow in medieval windows (2017)

#125

Post by tehwebguy »

nemo44x wrote: post #119
dragonwriter wrote: post #87

Earlier quoted context omitted.

> Otherwise a teacher works 30 hours a week when normalized to a 48 hour work year. This is part-time work. No, it's full-time seasonal work. > The sucker working retail could only dream. Retail generally doesn't require a four-year degree, plus a post-graduate credential as a basic qualification. Compared to professions that do, schoolteachers pay and benefits are between unremarkable and substandard.

Let’s just forget about their sweet pensions and lifelong benefits package. They have public sector unions that negotiate their compensation. I don’t think it’s teachers that are being bullied here.

> Let’s just forget about their sweet pensions and lifelong benefits package.

Many already have, as the local and state governments that control these pensions and benefits are constantly changing.

Re: Glass viscosity calculations debunk the myth of flow in medieval windows (2017)

#126

Post by JoeAltmaier »

nikisweeting wrote: post #2

Finally! I always knew my 7th grade science teacher was full of shit on that one, she was so adamant about some things that turned out to be wrong. This one was maybe more excusable because it was common to teach at the time. Maybe it ended up making us better students in the end because we learned to fact-check our teachers, and not to be adamant about things we only think are true (though I'm still guilty of that m…

I was taught in physical sciences that friction was proportional to weight and surface area. We were given blocks and a 'force meter' that was a bendy springy length of metal in a wooden calibrated frame. So pull blocks on a surface with the meter to measure friction. Try different surface area, stack them for multiples of weight, plot on a graph. Mine weren't coming out on a straight line. Other people noticed theres' weren't either, so they fudged their data points. I put down the honest ones. I got it 'wrong', they got it 'right'.

Of course that old myth was nonsense, my experimental method was correct, and I've felt the injustice for decades now!

Re: Glass viscosity calculations debunk the myth of flow in medieval windows (2017)

#127

Post by dragonwriter »

nemo44x wrote: post #119
dragonwriter wrote: post #87

Earlier quoted context omitted.

> Otherwise a teacher works 30 hours a week when normalized to a 48 hour work year. This is part-time work. No, it's full-time seasonal work. > The sucker working retail could only dream. Retail generally doesn't require a four-year degree, plus a post-graduate credential as a basic qualification. Compared to professions that do, schoolteachers pay and benefits are between unremarkable and substandard.

Let’s just forget about their sweet pensions and lifelong benefits package. They have public sector unions that negotiate their compensation. I don’t think it’s teachers that are being bullied here.

> Let’s just forget about their sweet pensions and lifelong benefits package.

Let's not; considering it doesn't make their total pay and benefita particularly good for the entry requirements, though it makes it somewhat less bad, leaving them only 11.1 percent behind comparable professions instead of 18.7 percent considering pay alone, as of 2017.

https://www.epi.org/publication/teacher-pay-gap-2018/

Re: Glass viscosity calculations debunk the myth of flow in medieval windows (2017)

#128

Post by everdrive »

_fi0w wrote: post #88
nemo44x wrote: post #42

Earlier quoted context omitted.

Most school teachers are full of it, but they don’t mean to. They are simply low level clerics in the church of truth. They recite a very lossy account of what they were ordained with at a likely low level institution. It’s not really their fault - people need jobs, the ministry needs repeaters, and the pay is bad. Your teachers weren’t the disease - they were just a symptom.

If only teachers were as intelligent and wise as HN’s anonymous commenters.

No disagreement with your jab. It's easy to be right once, when you get to choose whether you participate. If you had to speak for hours a day, days a week, you'd certainly be wrong some good amount of the time.

Re: Glass viscosity calculations debunk the myth of flow in medieval windows (2017)

#129

Post by gattr »

heikkilevanto wrote: post #113

Yeah, I learned this "fact" in school as well. Later I found a simple refutation: If a church window pane would deform by a measurable amount in 1000 years (say 0.5mm), then a 100-year old telescope or camera lens would be totally useless, and yet they seem to function all right.

To add some detail: a common minimum quality criterion for optical surfaces is λ/4 (divergence from an ideal surface), where λ is the wavelength used. For visible light this gives about 100 nm (though large professional telescopes are "figured" to more like λ/20). Any alleged glass creep visible in window panes over a few hundred years would quickly ruin any astronomical mirror (which definitely does not happen).

Re: Glass viscosity calculations debunk the myth of flow in medieval windows (2017)

#130

Post by Anther »

onion2k wrote: post #109
lookalike1974 wrote: post #105

Earlier quoted context omitted.

I would not disagree that your teachers failed you or vice-versa. But making grand pronouncements about people ("everyone else") and their problems as you see them ("without doing any critical thinking or experimentation of their own") and teachers too - and apparently based solely upon your personal experience in school and your thoughts on one church that just happens to be physically nearby you - isn't gonna convi…

I didn't suggest they're always wrong, or that all of them are wrong, or that some of them won't have done any checks on what they're teaching. I said that teachers will be wrong about things. That only means they're fallible and don't get things right all the time. If any teacher, or literally anyone else , is offended by the suggestion that they're human and could be wrong sometimes then I think I'm OK with offendi…

I’ve often said that it is not whether or not you offend someone; it’s whether or not someone is offended.

Offence is up to the receiver after all.

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