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ScienceNostalgia101

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Posts posted by ScienceNostalgia101


  1. https://imgs.xkcd.com/comics/nerd_sniping.png

     

    So this XKCD comic got me thinking... can the resistance of an electrolytic solution in water can be modeled as infinitely many resistors of infintesimal resistance? After all, the distance between the ions of electrolyte is a discrete quantity, but so is the number of said ions; or the number of water molecules between them; and we still model these things as continuous fluids.

     

    So obviously the resistors are in parallel; there are pseudo-infinitely many paths they can take. But no matter what path they take they have to jump between ions several times, so it's also in series. Is there any formula that could account for the combined series-and-parallel nature of a circuit through an electolytic solution?

     

    . . .

     

    Why yes, I did dream last night that I was caught in a thunderstorm with the car windows only partially rolled up, how could you tell?


  2. On 9/12/2020 at 1:42 AM, drumbo said:

    We need to decide where our priorities lie. Creating a buffer between forests and residential areas may prevent damage to property, but it may inadvertently put people in danger. The goals of maximizing the protection of property and the potential to protect people from danger are juxtaposed, we cannot maximize both.

    How would such a buffer put people in danger?


  3. 6 hours ago, CharonY said:

    A) I think zoonotic diseases are about 70% of emergent diseases, not of all

    B) The source for SARS-CoV-2 is still unknown, better not to spread wild rumours as facts

    C) Unless you want to ban all animal farms and limit folks entering animal habitats and eradicate all potential vectors, there is no way to prevent infections occuring. What we need to focus on is to identify, trace and limit transmissions. The issue is we keep forgetting that after a few years of no major pandemics (or if the happen far away).

    Encouraging alternatives to meat until we improve our healthcare system then sounds like it's a good way to make a dent in climate change and new pandemics alike.


  4. Got it, thanks!

     

    Speaking of The Simpsons...

     

    DISCLAIMER: I would not try this at home. NOR at any convenience store, for that matter.

     

    However, it reminds me of my curiosity about the issue of cryonics. I'm not sure who to believe on this issue.

     

    There are those who claim there are ways to survive being cryogenically frozen, if society would invest in them. Others dismiss it as hopeless. Are the former just wishfully thinking? Are the latter just trying to stop cryonics from cutting in on religion's afterlife action? If I found a professional service to freeze my body, would it be safer to do it immediately after death, immediately before death, or significantly before death in the context of some terminal illness or whatever? (Obviously I'm not going to cut drastically short whatever life I have now just on the offchance of being revived later.)


  5. Man, so many of the things I thought were no-brainers were a hell of a lot more nuanced than I thought.

     

    Very well, then. So what's the real solution to the current forest fires? More prescribed burns? More permanent firebreaks? Or just leaving California permanently and putting a giant pot of water over it hoping the boiling will make it pay for itself?


  6. Once again, California is on fire. Apart from the threats to property and safety, that's a lot of chemical energy in nature that is being squandered on a fire that isn't occurring underneath a boiler to boil water for food or electricity.

     

    I wonder, now... if society were to hire more of the recently-unemployed as loggers, and have them cut down enough trees that the wood could be burned in lieu of fossil fuels, (and/or be converted to paper and used as such before being burned) would this double as a way to make forest fires less severe, by the fact that there are fewer trees available, per square kilometre, to catch fire in the first place?


  7. On 9/8/2020 at 2:29 PM, swansont said:

    Is this not already the case in many cities? I know it is common in Washington DC, Manhattan (NYC), and downtown Vancouver BC Canada. I imagine a lot of it is driven by not wanting to have turn lanes taking up space, and if traffic is heavy enough, there are places where left turns are simply not permitted for two-way traffic.

    But in many smaller cities, where space is not as limited, two-way streets are still the norm, not the exception. Might lives be saved in the long run if we switched to one-way and took away the "basic human judgment" factor on when/where it's safe to turn left?


  8. So long as two-way roads have a grid structure, every intersection will include an option for turning left a green light.

     

    And every time a driver makes a judgment call on whether or not it's safe to do so, this risks getting them killed.

     

    I'm just wondering, wouldn't one-way streets create fewer options, per intersection, on which way to turn? For instance, if a north-heading street met an east-heading street, the north-heading cars could only turn right onto the east-heading street, not left. The east-heading cars could only turn left onto the north-heading one, sure, but you could also reserve one lane for traffic that is "joining" the street, such that they only merge into the traffic when they've caught up.

     

    Is there anything to go on as to whether or not replacing our existing grids of two-way streets with grids of one-way streets would constitute a net improvement in safet?


  9. I hear of dispute on the nutritional value of protein. Some say it's good for you and helps sustain sugars and starches for longer periods of time; others say it inhibits calcium absportion and Google suggests the truth is if nothing else in the same general direction.

     

    If the issue were the need to sustain sugars and starches for longer periods of time, would it be comparably healthy to eat sugars and starches in more frequently, but in smaller portions, such that the sugars and starches are sustained by the fact that you're eating them a little bit at a time?


  10. So last night I threw away some aluminum foil. It was in contact with food I was using it to keep warm, I didn't think I'd have much use for washing it and saving it, and I thought nothing of it until afterwards.

     

    I just realized... if there were some program to collect everyone's pre-washed aluminum foil, and/or wash it after collecting it, it could be arranged in an increasing variety/size of concave shapes, be used as a solar collector, and boil water, whether to distribute energy directly as heat, or to turn turbines and generate electricity.

     

    So why aren't we doing this? Have the fossil fuel and nuclear industry lobbies bribed politicians into not going for it or something? How expensive can it be to arrange aluminum foil in a concave shape, or find an absorptive, water-storing material to put at the focal point, especially compared to the lengths a nuclear or fossil fuel power plant goes to for the same water-boiling turbine-turning purposes?


  11. At this point, it's a thought experiment, though if it goes anywhere I'm considering writing my representatives about this.

     

    I want to impede waves because a lot of boats, even boats going through narrow straits in the ocean, encounter rough waves. I want to cut down on seasickness, but I don't know what will do the trick against ocean waves and ocean currents.

     

    Does it depend on whether the water is shallow or deep?


  12. 6hXZJed.png

     

    KtNScGq.png

     

    So I'm just wondering, short of building an outright bridge, what would it take to impede waves travelling through a strait? If one were to build barriers around the strait, would floating ones be adequate, or would they have to extend all the way to the ocean floor? Would they need to be on both sides, or would just the one upstream from the highest waves be enough to block out those particular waves?


  13. Yeah, convection sounds like it could only do so much good if there is an actual difference in dewpoint to allow sweating to help.

     

    Just so we're clear I'm referring to dark clothing in a hypothetical circumstance where all other considerations are already addressed. (Eg. Taking public transit everywhere you go, or not going out at night except through walking trails to which motor vehicles have no physical access at all, let alone lawful physical access, etc...)


  14. I keep hearing conflicting stories about what clothing is most effective at beating the heat. Some say white clothing is best to reflect the heat away. Others say dark clothing is best to absorb heat from the body and then radiate it elsewhere. (I would assume white during the day, dark at night?) Some say loose clothing is best to allow convection currents under the clothes, others say tighter clothing is best to radiate heat. Some say it's more effective to wear less, others to wear more. (It's possible the former's just an excuse by narcissists to show as much skin as possible, but it's possible the latter's an excuse by puritans to put modesty over health.)

     

    Do all these things depend on time of day, solar angle, temperature, wind, and humidity? Or are the answers more simple than the debates over this are made out to be?


  15. So I work at an office that is constantly warm in the summer, especially when the sun is facing the window. It has blinds, but those blinds aren't fully reflective, and I'm not sure if there is any legal liability to putting tinfoil outside them.

     

    However, there is another tinfoil-involving alternative that might work; indoor concave mirrors to collect solar energy.

     

    https://www.youtube.com/watch?v=8CLRTa_ocmo

     

    I'm thinking if I did something less precise, but still in a general concave shape, to concentrate all the solar radiation entering the office through the window on a darkly coloured kettle and use this to boil water for coffee or tea.... if I and/or my colleagues were to drink that tea or coffee, would the general effect on how warm it feels in the office, including the heat from the coffee I'm drinking, make it equivalent to the warmth from if all that solar radiation were absorbed by the walls or floors, or would the net effect be a cooling effect?

     

    (Disclaimer: I intend to ask my boss well before going through with it... but I intend to ask you guys well before asking my boss.)


  16. 3 minutes ago, swansont said:

    A temperature decrease causing a pressure drop from PV=nRT assumes V and n are constant (or only have small changes) which are probably not good assumptions.

    If water condenses out, n will drop. The atmosphere does not have a fixed boundary, so V may effectively be lower. You would have to know the size of those effects to draw a conclusion about P

    What if there is less atmosphere?

     

     

    Ah, the condensation part makes sense, then.

     

    So is phase change of compounds/elements involved the only means by which "n" changes? Or is it also possible for an expanding/contracting/otherwise changing atmosphere to shoot more matter out into space and/or attract more matter from outer space?

     

    And another thing I forgot to consider earlier on, as you mentioned the lack of a fixed boundary... Earth's atmosphere is exponentially decreasing with distance, rather than having any arbitrary "threshold" where Earth ends and space begins. So that raises the question... what would decreasing V be equivalent to in that context? An exponential function with a different base? Different rate of change? Both? Neither?


  17. From my understanding, it is not only possible to have a rotating vector field with a point in its centre where the velocity vector is precisely zero, but that the reasons to expect one follow from the fact that if the surroundings are rotating about one point, they are not moving at that point.

     

    But what if you had a moving vector field? For instance, let's say you had the centre of some galaxy, about which all the stars around it were orbiting, moving through space. Obviously in the reference frame that is that moving galaxy, the velocity of that centre is zero. But in some external reference frame not moving parallel to that galaxy, that centre is not zero. Does there have to be some other point in that galaxy, then, at which the velocity is zero in the other reference frame, or is there some means by which literally no point in that galaxy has a zero point?

     

    Not sure whether this is better suited to the math or physics board; thought I'd put it here since I assume chemistry and geology have used for the math of rotational dynamics as well.


  18. So when Day After Tomorrow came out, a lot of people were saying online that a temperature decrease would, per the ideal gas law, decrease pressure, and that the movie failed to portray the effects of this drawing air out of enclosed surfaces. This summer after noticing the office's alcohol based sanitizer containers dripping from overpressurization the topic has come to mind again.

     

    However, pressure is also proportional to the weight of the air above a given surface. So if the surface area of Earth remains the same, would that not mean the average pressure has to remain the same? Would therefore the volume of the atmosphere contract? (I would assume thermal expansion of liquid/solid interior of the Earth is at a less drastic rate.)

     

    Conversely, real-life climate change is known to increase average global temperatures, which I would presume increases the total volume of the atmosphere. However, it's also known to be more pronounced at the poles than the tropics (I often see this pointed out but I haven't come across anything pointing out why) so would that mean the shape of the atmosphere as well?

     

    This also got me thinking; for the ideal gas law; or some hypothetical differential equivalent thereof; to work at every point in space, that would mean there has to be more volume per unit space where the temperature's higher. Doesn't this suggest the present shape of the atmosphere is actually different than the shape of the Earth? That it would bulge more at the equator than the Earth does, and shrink more at the poles than the Earth does? If climate change expands the atmosphere more rapidly at the poles than the tropics, will this create an atmospheric shape more similar to that of the Earth? (Ie. Larger but more "to scale" than before?)


  19. On 5/8/2020 at 3:14 PM, Strange said:

    Yes. (But you would need to find a material for the prism that is transparent to those frequencies; I don't think normal glass is.)

    Would a diffraction grating work? I've long been interested in splitting sunlight into its UV and visible rays separately.


  20. 53 minutes ago, MigL said:

    Yeah, they once used animal fats as fuel for lamps.
    You want to go back to that instead of using electricity ?

    What about reducing human population also ?
    I find it ironic that AGW will make life difficult, or impossible, for a sizeable fraction of human and animal populations, and your solution is to 'cull' a sizeable fraction of human and animal populations.
    Doesn't that defeat the purpose of combatting AGW ?

    No. AGW wouldn't just reduce population, but would also cause human suffering in the process. Conversely, the fewer people are born, the higher the quality of life per person, if only for having more natural resources per person, let alone lesser effects on pollution.

     

    But the question of how to get there is still a valid one. The non-coercive market tactic that is the enormous cost of raising a child has slowed birth rates very gradually, but not quickly enough to stop global warming. If we were to force the latter, it would be considered dishonourable to resort to such a coercive tactic.

     

    On top of that, a lot of people see reduced birth rates as a short-sighted solution to the problem anyway; what happens in a few decades' time when Gen Xers retire and there aren't enough tax dollars from newly employed workers born in the 2020s to keep them alive? We could let in more immigrants to stem the tide, but what will that do for countries into which no one born elsewhere wants to set foot? 

     

    At least with animals, the solution is clearer, because they didn't have grandparents to look after. Either hunters already killed them all, or other animals did.

     

    A flood is harmful to a person because once the flood arrives, they're living in filth. Animals were living in filth anyway so they had less to live for. For human beings, the day they killed each other in the aftermath of a hurricane was the most important day of their lives. For animals, it was Tuesday.

     

    As such, the alleviation of human suffering should take priority over an animal's life, which would've been taken by another animal if it wasn't by us.

     

    People have backyard fireplaces even though they have indoor lights. I'm sure having some of their light and heat be provided by burning animal fats wouldn't be too unthinkable anyway. (Personally, I kind of like that barbecue scent it creates.)


  21. In my early teen years, I loved playing with vinegar and baking soda at home during the summer months, but I hated chemistry labs at school. The crowded, hectic, noisy, structured, time-constrained stressful environment wasn't exactly as charming as a bottle popping in my backyard in the warm summer sun.

     

    And now, the next generation of students is facing a situation where school isn't just stressful, but could be a literal threat to life and limb. We are told the teacher must supervise a student in person when they're carrying out chemistry labs; that doing these at home at a distance would be reckless endangerment.

     

    Well, sending kids to school during a pandemic is also reckless endangerment, so the point is moot.

     

    Is there any way to have parents and/or specialized private tutors sign a contract promising they'll supervise the student when they carry out these chemistry labs instead? We hear of parents struggling to help students with homework, but lab safety is more akin to common sense than to esoteric details, and the great outdoors, so long as the chemicals are downwind, reduces the need for a fume hood. Those who work more quickly no longer have to "find other course work" they can do while waiting for the rest of them to finish up, and the ones who work more slowly won't be feeling the stress of how to handle a paraffin wax candle with the feeling they're holding everyone else back making them more nervous... and possibly more clumsy in the process.

     

    The parents who DO want to help their kids carry out these labs will reduce the burden on the tutoring industry, which can handle the rest, and we might be able to not only keep chemistry labs alive during this pandemic, but create a new model of chemistry lab from which more enjoyment can flourish.

     

    The question of how to document whether the students were actually doing these labs or only pretending to is a real one, but there could be all kinds of potential alternative solutions. My personal favourite would be for parents or tutors to film them, just as an incentive for honesty. We already have video projects in media classes, so if the legitimacy of video evidence for the purposes of school were in doubt, so too would the validity of media class assessment.

     

    But regardless of the supposed flaws of that option, that doesn't mean we need to go back to the old model of doing things, especially during a pandemic.

     

    What say you, Science Forums? Are at-home chemistry labs an option worth exploring? If they aren't, is there any way to have them carried out in a setting other than either "at home" or "at school"?

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