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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)

#161

Post by monk_e_boy »

tidenly wrote: post #32
lozaning wrote: post #22

Earlier quoted context omitted.

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.

Especially for hydrofoils. Makes no sense

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

#162

Post by eitland »

JoeAltmaier wrote: post #126
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 there…

Our physics teacher were clearly happy when we got weird results and actually wrote down what we saw and wrote a comment on the difference between expect and observed results.

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

#163

Post by pjmorris »

solipsism wrote: post #94
pjmorris wrote: post #30

Earlier quoted context omitted.

Not the OP, but a fourth grade substitute teacher made the claim that we always saw the same side of the moon because it didn't rotate. I don't know what got to me the most: that she didn't understand, that my attempt to explain it didn't go over, or that the other kids in the class didn't get it either. In any case, I've been working on improving my explanations ever since.

And your beef is that it does rotate, at a rate of one rotation per revolution? Sounds kind of pedantic to me, and confusing (certainly to kids).

I'll grant that I was a pedantic fourth grader. And I'll grant that the other kids didn't care. Still, seems to me that the teacher could at least skip the topic if it's confusing.

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

#164

Post by bluGill »

themaninthedark wrote: post #142
redis_mlc wrote: post #36

Earlier quoted context omitted.

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…

How does that work? If the water is being used by the industrial facilities then the water pressure/flow rate would drop. Unless the facilities are adding dirty water to the pipe to push pressure back up after they remove it? But even then, unless they routed the pipe from the water treatment facility to the industry first, only the areas downstream from the industry would be affected. More likely is that the water i…

I would guess that they have a treatment system that isn't big enough, and they pump in unfiltered water to make up the difference when the treatment plant cannot keep up.

Even in the US I know of cities that have had boil orders because the treatment plant couldn't keep up and they pumped in untreated water. The cases I know of the unfiltered water made it in via weather events (the treatment plant is on the river and it flooded. Also a case where the power went out on a big surge and so they hardwired the pumps to the well bypassing treatment until the treatment controller boards could be replaced.)

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

#165

Post by askvictor »

torben-friis wrote: post #3
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…

What other unsubstantiated claims did she make?

Centrifugal force is a common one: https://xkcd.com/123/
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