ScienceNostalgia101

I'm not sure whether this belongs in the physics of movies thread or not, but I figure I should have a spearate thread for video games given the interactive nature of the medium. In one part of Kaizo Mario 3, Mario is temporarily in projectile motion, until his trajectory crosses paths with a waterfall. At this point, the viscosity of his surroundings is no longer negligible, and therefore, he can push his feet downward against the water to propel himself upward. I assume it's exaggerated, and that one couldn't possible propel oneself to THAT extent in real life. But at the same time, this leaves me wondering whether it's possible to "slightly" propel oneself this way, or not at all because it violates conservation of momentum. I know in horizontal motion, one can swim by pushing the water back and therefore propelling oneself forward; it's a matter of encountering less water resistance when putting your hands in front of you than when pushing the water behind you. Could the same thing work vertically? Does it depend on whether one positions oneself for it before entering the waterfall or after?

But is eating bat or snake meat safe so long as it's cooked long enough? Is there any virus or other pathogen that'll be present no matter the temperature to which it is heated or the duration for which it's heated to that temperature? While I'm at it, I know it's a distinct topic, but... does the same apply to human meat? I'm not considering trying it or anything, but I know a lot of people in desperate circumstances end up resorting to it, is that safe as long as it's heated enough or is there some other reason that's unsafe?

Not sure whether this is better for here or Biology, but I'll put it here for now. I assume most of you have already heard of China's coronavirus outbreak, but in case you haven't, a little refresher... https://www.businessinsider.com/wuhan-coronavirus-chinese-wet-market-photos-2020-1 A. So does this suggest doing farming within the city limits of a major city is more likely to spread disease than relegating the farming tasks to small towns? Does it depend on whether it's meat farming or just vegetable farming? Either way, how come China often does their farming in major cities, while in the United States, farming's considered a "small town" thing? B. Within the idea of farming in cities in particular, is it safer to slaughter animals before bringing them to a market, or after? Does the former risk causing insects and/or microbes to get at them faster or something? C. Within the latter, is it safer to cook the meat before bringing it to the wet market, or to leave the customer to cook it? Would "cooked" meat have only the illusion of safety since in an open air market insects and/or microbes could get at it? D. Is there any animal that's dangerous to eat no matter how long you cook it for?

Another question now (sorry to keep bumping this, but it's not letting me edit the previous post now) but I was wondering another thing. I mentioned before the question of a concave arrangement of various small mirrors, vs. one large concave mirror, in the context of solar collectors on land. It was pointed out that in that context, it's better to have a number of small mirrors than one large one. Does the same apply to thermal solar power at sea? If one were to mass-manufacture, and then arrange into a concave pattern, a series of small mirrors, could most of the thermal energy that would otherwise fall on the Atlantic Ocean instead be captured by these solar collectors, if they were made to float in the ocean? (Presumably tied to each other and the land, to prevent them from being swept away by the currents...)

Looking at various chemical reactions, I used to see parallels in acidity and alkalinity to the energy concept. Acids and bases neutralize; sort of temperatures contrasting. Acids react with metals to form neutral hydrogen and salt; but those metals would if electrolyzed would've become alkaline, so it almost looks like the "alkalinity" equivalent of latent energy. And of course, if you burn plants, the ashes are alkaline, but the gases could be reacted with water to form acids. A divergence between alkalinity and acidity, if you will. But then I found this. https://www.youtube.com/watch?v=hLHfN7GvAyI#t=2m11s This person forms a strong acid; hydrochloric acid; by reacting together two substances for which neither of them are strong acids. The other product of this reaction is not a strong base, so it's not a "divergent" reaction either. Is there some sort of "latent" alkalinity contained here? If so, could something like this be used to reverse the effects of acid rain by, let's say, reacting together substances that aren't strong bases to form a strong base, with the other product not being a strong acid, therefore increasing the pH of the bodies of water?

For the record I wasn't referring to using indoor appliances outdoors so much as whether or not there's some outdoor equivalent that'd still keep it cold on abnormally warm (as far as winter goes) days. In any case, I was surprised to learn they manage to store ice all year, let alone through the occasional warm day within winter. I guess anything well insulated enough with enough ice in it would prevent the temperature from going too far above freezing, if only by convection. (Though I'd be terrified of accidentally locking myself in one.)

Can't edit prior post. Have a new energy-saver inquiry. Is it more energy-efficient, in the wintertime, to have an outdoor refrigerator/freezer, such that the temperature difference between the outdoor air and refrigerator/freezer is less than that between the indoor air and refrigerator/freezer, or less efficient because an indoor refrigerator/freezer releases heat into its surroundings anyway?

Wasn't sure whether this belonged in physics or chemistry, but being that from my familiarity with physics, heat makes objects LESS conductive, I assume it's chemistry that explains this. (And/or gives us enough to go on as to whether or not it's a hoax.) Starting at 4 minutes and 13 seconds in, you can see a tree branch that fell on two power lines conduct smolder; presumably from conducting electricity between them. However, it takes more than a minute for any flames to become visible. Within seconds of the flame becoming visible, you can hear audible electrical arc sounds for a few seconds before the tree branch outright explodes, turning the smoke given off from grey to brown. So what's going on here? Does the electricity directly cause chemical reactions that produce compounds more electrically conductive than those of the tree branch itself? Or does the smoldering cause that? As well, why the abrupt shift from flame to explosion if it took more than a minute for flames to appear?

Apparently there's digestive problems from them as well. https://www.healthline.com/nutrition/sugar-alcohols-good-or-bad#section6 Not sure if it'd be worth it for the buzz. The issue with the corn syrup thing is that the federal government itself won't call it sugar. So why the impetus to refuse to in this context even though fructose is referred to as "a sugar" in biology classes? https://www.nbcnews.com/health/health-news/feds-say-high-fructose-corn-syrup-not-sugar-flna805762

I forgot to reply to this earlier. I'd like to take this opportunity to ask; should this be the same thread or a separate one? Because I can think of some things that blur the distinction between "increasing power production" and "reducing current power usage." For instance, suppose that instead of throwing paper waste away, one were to burn it for heat. There are two ways I can think of for this heat to be used: A) Put a metal tube above the fire that does not allow smoke to enter, but allows the heat energy to conduct through, so that enclosed air molecules can warm up from contact with this surface and enter any household to which this tube is connected, or... B) Just directly boil water above it and use it to cook food or brew coffee. Would either of these be more efficient; or less; than transporting everyone's paper waste to an incinerator that uses higher temperatures to generate electricity? (Efficiency of an engine; if I recall correctly, is a strictly monotonic function of difference in temperature between the hot reservoir and cold reservoir, correct?)

So a lot of companies try to get around admitting to the sugar content of their products through special pleading. They'll refuse to count high fructose corn syrup as sugar, for instance, presumably by the fact that it's technically chemically distinct from sucrose. This raises a key question; how was sugar originally defined? Did the original definition include all things chemically counted as sugars, or just a narrower subset of them?

So does that make it misleading, then, if its actual scientific name is hydrogen oxide?

Water is easily the most common oxide of hydrogen. Its two hydrogen atoms for every oxygen atom correspond to the 2- charge of oxygen and 1+ for hydrogen. I would think, if only for those reasons, "hydrogen oxide" would be the most appropriate name for it. To cap it off, other covalent hydrogen compounds seemed to be named that way. H2S, for instance, isn't called "dihydrogen monosulfide." However, I always hear "dihydrogen monoxide" referred to as the name for water when people are using it to mock environmental scares. I see two explanations for this: A. They're actually that ignorant about this, which would make it seem rather hypocritical to then paint environmentalists that way, or... B. They're deliberately misrepresenting the way chemical names work to catch people off-guard, whether to make it sound scarier than water's actual chemical name would be, or to avoid allowing anyone an opportunity to think "hydrogen oxide, eh? Hmm... what is formed when hydrogen is burned in oxygen again?" Is there a legitimate reason H2S is more commonly referred to as hydrogen sulfide and H2O as dihydrogen monoxide, or am I onto something here?

Magnification... as in camera magnification, or is there an equivalent for "field of view" in the context of eyesight?

Depends on the temperature, I think. At higher temperatures a 1% shift in humidity counts for more than that of lower temperatures. In any case, thanks for the clarification.

Again, a network of permanent firebreaks could isolate the fire to one grid square at a time (presuming it didn't spread) but that isn't denying them fire altogether. It's just having one grid square catch fire at a time. So they'd still replenish themselves with fire, just on a smaller (if more frequent) scale.

Not quite, just that all that excess water vapour pumped into the air would shift the equilibrium somewhat, sort of like how a weight hanging from a spring shifts its equilibrium. Still an unreasonable assumption?

https://www.youtube.com/watch?v=y-4qqcCxD6g So the following video shows a method; involving hydroxides, silver nitrate, and ammonia, for depositing silver directly onto a surface. 1. Could any excess silver (ie. not deposited onto the surface) be re-used? 2. Could something like this (make the metal deposit onto the surface) be used with cheaper reflective materials, like aluminum? 3. How cost-effective would this be, as a mirror-making method? Does it depend on whether it's a flat mirror, concave mirror, or convex mirror? Would this be good for creating especially large concave/convex mirrors if you already had a large surface onto which to make the silver deposit itself?

So this parody of an old video game portrays a (fictional!) oil explosion on an island from a distance; and the resulting duration of silence before the noise. Obviously, if we were directly given the angle to one end of the island and angle to another we could use geometry to estimate this fictional island's length. But here we're only given the distance to the island (via sound delay) and the fraction the island takes up of the field of view. This got me wondering whether or not "field of view" can be used to estimate "range of angles" between the point of observation and the object being observed. For instance, is there a function relating what fraction of a field of view an object takes up to the difference, in angle, between a bearing to the left side of the object and a bearing to the right side of the object? Does it depend on what these angles are, or only on the difference between them?

Trouble is, cities that have a solid, pragmatic reason to be placed where they do also suffer the consequences of forest fires. (Fort McMurray comes to mind.) I can see why people who built their homes in the middle of nowhere could reasonably be considered at fault, but what about cities with plainly practical reasons for their location? Why is there not more of a movement to create large enough firebreaks to stop the fire? Or irrigation systems within those firebreaks that could be remotely activated to spray the embers?

Forgot I even had this thread! Asked this for the purposes of Christmas-themed problems for my students. Realized that, tempting as a "Santa Clausius" pun would be, other topics than Clausius-Clapeyron worked anyway. That said, I'm still curious, and I'm not sure I fully understand the answer. I assume what you're saying is that if the rate of change in pressure is proportional to the rate of change in entropy with volume... therefore that entropic processes like evaporation will have to change pressure in accordance with that proportionality, making the effect of being a dissolved substance evaporating same as that of being a liquid evaporating? In a nutshell, is that a "yes"? Also, while I'm at it, why is it called the Clausius-Clapeyron equation if Clausius only came into the picture decades later?

I mean the latent heat of vaporization; as in, yes, it's still around, but more of it as potential energy and less as kinetic? Sounds good, but sounds like it'd take a while to make such drastic changes to infrastructure, whereas climate change needs to be dealt with more urgently. Maybe something to think of after the climate crisis is resolved?

This issue has long been an obsession of mine, since before I even really had an accurate understanding of what it was. I used to think embryonic stem cells came from aborted fetuses; yet I get angry when hearing others spread the exact same myth. (For the record, for anyone reading, they come from in vitro fertilizations or from cloned embryos.) To avoid falling into the same sort of trap as before, I want to make sure I know what I'm talking about amidst an issue left murky by controversy. A. One popular talking point against embryonic stem cell research is that because other stem cells have (supposedly) gotten better results. Firstly, aren't they supposed to be useful for different purposes than other stem cells are? Secondly, how much time and/or money has been poured into research with embryonic stem cells vs. any other type of stem cells? B. Another is that you can supposedly "program" non-embryonic stem cells to act like embryonic ones. I heard a lot about this about a decade or so ago when Obama was lifting funding limits on this research, but it hasn't been in the mainstream discussion much since. Have any of you heard any updates on the efficacy of this one? C. There is also discussion on the tradeoff between public and private sector embryonic stem cell research. The supposed benefit of the latter is that the taxpayers who object to it can wash their hands of direct culpability for it, by the fact that it isn't their money going toward it. The tradeoff, however, is that any private company that profits more from the disease than they would from a cure has a perverse incentive not to cure that disease. As well, any cure they do release, they can patent and exorbitantly overcharge for. Critics of public funding for embryonic stem cell research claim that private companies would be involved in this research anyway. Is this true? If so, why does the government give private companies public tax dollars, and why can't they just cut out the middleman and do the research themselves?

Enough people prioritize the environment over human lives to prevent thinning and firebreak-grids? Where were these people when the Lac Megantic derailment was used as an excuse for pipelines? (Putting aside the use of trains for other dangerous goods than just oil.) Quite frankly, that kind of thing makes me wish they'd not only create permanent firebreaks but salt the Earth beneath them as well.

Hmm... what about the fact that some of the thermal energy that would otherwise go toward increasing surface temperature instead goes toward boiling water? Would that decrease temperature while simultaneously increasing humidity? (Assuming some of the water vapour above each pot of food/coffee escaped into outdoor air before condensing?) As for me, I don't cook. I work in places that have food available and/or eat canned fish/frozen dinners/peanut butter sandwiches for protein. Perhaps not the healthiest approach, but it's what I'm used to.