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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)

#31

Post by jiggawatts »

zamfi wrote: post #5
torben-friis wrote: post #3

Earlier quoted context omitted.

What other unsubstantiated claims did she make?

I'm not the original poster, but I was shocked by how many of the otherwise super smart friends I had in college were taught common falsehoods in high school. For example: the idea that your veins look blue through your skin because the deoxygenated blood in them is blue, and that it only turns red outside your body because it's exposed to oxygen.

One of my favourites is the myth that Iodine doesn't melt: https://www.youtube.com/watch?v=dPIaEWd8zf4

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

#32

Post by tidenly »

lozaning wrote: post #22
monk_e_boy wrote: post #17

Earlier quoted context omitted.

Or how wings work.

For anyone thats interested in what the parent is talking about: http://www3.eng.cam.ac.uk/outreach/Project-resources/Wind-tu... I've had people get like legit upset at me when i correct this.

My god, thank you. I remember as a kid this explanation "the top has to move fast to meet the bottom stream at the trailing edge" always confused the hell out of me. Why do the top and bottom have to meet? How would they know? Even as a 10 year old it confused me no-one could answer this.

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

#33

Post by bigbubba »

deelowe wrote: post #29
causality0 wrote: post #28

Earlier quoted context omitted.

I had an electronics professor who in 2012 was adamant that in five years smartphones would be using x-ray transceivers to communicate with cell towers.

I think your professor read about millimeter wave and misunderstood. I've had others confuse the two in conversation as well.

Confusing millimeters and nanometers? How? Visible light sits between the two, they're not even close.

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

#35

Post by pfdietz »

parsecs wrote: post #19
zamfi wrote: post #5

Earlier quoted context omitted.

I'm not the original poster, but I was shocked by how many of the otherwise super smart friends I had in college were taught common falsehoods in high school. For example: the idea that your veins look blue through your skin because the deoxygenated blood in them is blue, and that it only turns red outside your body because it's exposed to oxygen.

Or how reentry heating is apparently caused mostly by friction. (Compression of air is the main cause in actuality)

No, actually friction is closer to the truth. It's air running into air at a shock, a process that generates entropy, just as friction does.

Compression is a process that is adiabatic, generating no entropy. And in an ideal gas the density increase across a shock reaches a finite limit even as the mach number goes to infinity.

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

#36

Post by redis_mlc »

bluGill wrote: post #24
redis_mlc wrote: post #15

Earlier quoted context omitted.

> The only major one I remember is that water is conductive by itself. Most people don't know that pure water is an insulator. However, in a practical sense that's ok since it's unlikely any pool of water is pure. So for safety reasons involving electricity, one has to assume that any pool of water can conduct electricity.

My uncle works for a water treatment company. Medical manufacturers often come to him saying his equipment is off because they open the test port ran the pure water into a clean glass and it tested below specs. He then has to explain that in the 30 seconds between opening the valve and the test the water absorbed enough impurities to fail the spec. The input water was fine.

Another interesting anecdote about water treatment facilities is the situation in Asia.

For example, Jakarta has a water treatment facility, but every tourist gets stomach illness there. The reason is that industrial facilities siphon off the treated water, and by the time homes and hotels get any, it's untreated.

To give you an idea how bad it is, tourists generally don't drink tap water, but they still get ill from the washed dishes, or not closing their mouth in the shower.

(Bali can always find money for road construction (they built two impressive underpasses in the last 6 years), but never enough for a power generation plant, so has continual brownouts.)

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

#37

Post by dheera »

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…

Lots of grade school teachers are full of shit.

I had one that claimed that a pentagon had 1 line of symmetry because "the top is bigger than the bottom".

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

#38

Post by elmomle »

dheera wrote: post #37
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…

Lots of grade school teachers are full of shit. I had one that claimed that a pentagon had 1 line of symmetry because "the top is bigger than the bottom".

Allow me to be dumb for a second--isn't that the case? I mean, if you label the vertices/edges then yes a regular pentagon has five distinct lines of symmetry, but typically people talk about lines of symmetry in a context where vertices are unlabeled, no?

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

#39

Post by ClumsyPilot »

bigbubba wrote: post #33
deelowe wrote: post #29

Earlier quoted context omitted.

I think your professor read about millimeter wave and misunderstood. I've had others confuse the two in conversation as well.

Confusing millimeters and nanometers? How? Visible light sits between the two, they're not even close.

Well, i once confused packaging and ordered ~100 kg of toiler paper

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

#40

Post by coldtea »

bigbubba wrote: post #33
deelowe wrote: post #29

Earlier quoted context omitted.

I think your professor read about millimeter wave and misunderstood. I've had others confuse the two in conversation as well.

Confusing millimeters and nanometers? How? Visible light sits between the two, they're not even close.

>Confusing millimeters and nanometers? How? Visible light sits between the two, they're not even close.

Compared to kilometers and parsecs, they're extremely close...

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