Wikipedia:Reference desk/Archives/Science/2020 January 27

= January 27 =

Health effects of drinking human blood
If a person were to drink human blood, would that be fattening? Freeknowledgecreator (talk) 06:33, 26 January 2020 (UTC)


 * At this point I am getting a thirst for drinking troll blood. 67.164.113.165 (talk) 09:34, 26 January 2020 (UTC)
 * It is a serious, matter of fact question. I am looking for a serious, matter of fact answer. If you find a question offensive for some reason, you obviously do not have to respond to it. Indeed, it is probably better to make no response in such situations. Freeknowledgecreator (talk) 09:40, 26 January 2020 (UTC)
 * Please try google before asking further stupid questions here. Example. 67.164.113.165 (talk) 09:51, 26 January 2020 (UTC)
 * Insulting me really serves no purpose. If you don't like the question, don't respond. That should be simple enough, shouldn't it? As for those Google hits, none of them, at a quick look, address the specific question of whether drinking human blood would be fattening. Freeknowledgecreator (talk) 09:54, 26 January 2020 (UTC)


 * See Black pudding. Not about drinking it, but eating it. Seems like it depends on the recipe. HiLo48 (talk) 10:05, 26 January 2020 (UTC)
 * You Australians have some crazy black pudding recipes. Most other places use pork blood for their black pudding although some may use sheep or cow blood. Various other blood sausages exist but human blood sausages is a new one to me. (Discounting vampire fiction.) Nil Einne (talk) 10:41, 26 January 2020 (UTC)
 * Are we sure Mrs. Lovett never made sausages instead of pies? HiLo48 (talk) 10:50, 26 January 2020 (UTC)
 * As I have previously responded the level to which any food is fattening depends on how much you consume compared with the amount of effort used to burn the consumed calories (this is only part ot the complex problem of obesity) See Blood as food. Where would you propose to obtain the human blood, or is this a hypothetical question? Richard Avery (talk) 15:36, 26 January 2020 (UTC)
 * The question is, of course, entirely hypothetical. Freeknowledgecreator (talk) 23:30, 26 January 2020 (UTC)
 * (Singing) Use HiLo48, if you must watch your weight! Gråbergs Gråa Sång (talk) 17:08, 26 January 2020 (UTC)
 * (e/c) These questions are pointless, not because any one of them are "stupid" but because you don't seem to be getting the gist of the answer: NOTHING in and of itself can just be called fattening or healthful or thinning or good for reducing belly fat or any of the other tiresome variations you've raised. The dose makes the poison and no one eating event is going to change your body's fat content appreciably. You need to consider the entire diet, the body of the consumer, their level of exercise, their general fitness and metabolism, and other things. Matt Deres (talk) 15:45, 26 January 2020 (UTC)
 * You have a point, but it still serves some purpose to ask whether a given food or substance would be fattening. If necessary, interpret the question, "is x fattening?" to mean, "If a person consumes x on a regular basis, would that be fattening?" Freeknowledgecreator (talk) 23:04, 26 January 2020 (UTC)
 * What would be an average serving size? Bus stop (talk) 23:52, 26 January 2020 (UTC)
 * Irrelevant. I am simply noting that even if there is no food or substance that is automatically fattening in every situation, it is still legitimate to speak of a given food or substance as having a tendency to be fattening, hence the point of the questions I've been asking. Freeknowledgecreator (talk) 00:13, 27 January 2020 (UTC)
 * That's a valid point. My guess would be human blood would be similar to blood of some of the other creatures we eat. One exception might be Horseshoe crabs, which use Hemocyanin to carry oxygen instead of Hemoglobin, as used by humans. Would this be cooked or uncooked human blood? We also have to be concerned with blood-borne disease—"Since it is difficult to determine what pathogens any given sample of blood contains, and some bloodborne diseases are lethal, standard medical practice regards all blood (and any body fluid) as potentially infectious." Bus stop (talk) 00:22, 27 January 2020 (UTC)
 * No, the serving size is very relevant. If I eat 1 g of chocolate every day, the impact on my weight would be very different from what it would be if I ate 1 kg of chocolate every day. "On a regular basis" is also vague to the point of uselessness. Once every 10 years and every 10 minutes are both "on a regular basis". --Khajidha (talk) 14:01, 27 January 2020 (UTC)
 * What I had in mind by "on a regular basis" was daily. Freeknowledgecreator (talk) 22:46, 27 January 2020 (UTC)
 * 1) Then say so. We can't read your mind. 2) The portion size would still be important. If I eat one potato chip every day that is different from eating one snack size pack of potato chips every day. Let alone eating one family sized pack of potato chips every day. For what seems to be the millionth time, how much of a food is eaten and how often it is eaten and how active the consumer is are much more important to your health and weight than what food is eaten. --Khajidha (talk) 15:26, 28 January 2020 (UTC)
 * For portion size, let's say, sufficient to satisfy the sort of hunger a person is likely to feel on waking up early in the morning, after having had three meals sufficient to meet normal physical needs the previous day. That's quite specific. Freeknowledgecreator (talk) 01:53, 29 January 2020 (UTC)
 * You would still have to account for whatever else the person ate that day. And for their activity level. And for their personal metabolic rate. There simply is no way to say if a particular food is "fattening" in an absolute sense. --Khajidha (talk) 12:28, 29 January 2020 (UTC)
 * I know. The question, is something fattening, should simply be understood to mean, does it have a tendency to be fattening? I'm not surprised that no one has been really been able to answer my question whether this would be true of human blood, and perhaps this whole discussion should be archived. Freeknowledgecreator (talk) 22:24, 29 January 2020 (UTC)
 * Just call him Drac. ←Baseball Bugs What's up, Doc? carrots→ 08:12, 27 January 2020 (UTC)
 * Please, I already noted the question was entirely hypothetical. Freeknowledgecreator (talk) 04:32, 28 January 2020 (UTC)
 * Whatever you say, Drac. ←Baseball Bugs What's up, Doc? carrots→ 05:45, 28 January 2020 (UTC)

Bransden and Joachain, Introduction to QM
Does anyone know this book? Do you recommend it as an introductory QM text for someone with a reasonable math background but not much physics beyond elementary mechanics? Thanks. 173.228.123.190 (talk) 09:46, 27 January 2020 (UTC)
 * And what is a reasonable math background? That is, does that mean first-year calculus, or something beyond that?  I think it would be very difficult to deal with quantum mechanics without a knowledge of first-year calculus.  Robert McClenon (talk) 20:46, 27 January 2020 (UTC)
 * Well, enough math for introductory QM ;). Question is more about the physics required for this specific book, and also whether it is a good book for self study, has good exercises, etc.  Thanks. 173.228.123.190 (talk) 01:43, 28 January 2020 (UTC)

Oxford Electric Bell
How is the Oxford Electric Bell not a perpetual motion machine? Thanks. Anton 81.131.40.58 (talk) 11:29, 27 January 2020 (UTC)
 * To quote the article, "The Oxford Electric Bell does not demonstrate perpetual motion. The bell will eventually stop when the dry piles have distributed their charges equally if the clapper does not wear out first." Seems pretty clear. But besides that, a "perpetual motion machine is a hypothetical machine that can do work indefinitely without an energy source. This kind of machine is impossible, as it would violate the first or second law of thermodynamics". Freeknowledgecreator (talk) 11:36, 27 January 2020 (UTC)


 * It's battery powered. When the batteries run flat, it will stop. It's likely that it may wear out mechanically first. Andy Dingley (talk) 12:34, 27 January 2020 (UTC)


 * Here is a very lovely piece of light scholarly reading: The Methods of Modern Logic and the Conception of Infinity (1907), available at no cost on JSTOR. In this piece, Richard Haldane, 1st Viscount Haldane extolls the evolution of modern scientific and philosophical understandings of the truly absurd mathematical facts that pertain to the "conception of infinity."  This is a paper that was read in front of a bunch of smart people at Oxford - "a long time" ago, but ... that was not "an infinite time" ago.
 * In simple words: a machine can run for a long time, and that is different from running "perpetually." Great thinkers have studied the difference between "a long time" and "perpetuity" ... for ...a long time.  (...But, even our best and greatest human scholars have not studied this philosophical precept for a perpetually long time).  Over a long period of time, there has been a gradual change in the general philosophical consensus-understanding about the difference between these two concepts.  In technical settings like physics and mathematics and thermodynamics, we now have very precise ways to distinguish "a long time" from an "infinite" amount of time.  And we even use different words in common speech to distinguish these concepts.  For example, we have a word, in the English language: "perpetual"; and in certain cases, we use this word; and in other cases, ... we do not apply that adjective.
 * In the case of the Oxford Electric Bell, ... intelligent people do not apply the adjective "perpetual" to describe the motion of the machine.
 * ...So, where is your confusion? This is a machine that runs for a long time, and it is not a perpetual motion machine, and no reasonable person even says it is a perpetual motion machine.
 * Nimur (talk) 17:36, 27 January 2020 (UTC)
 * To try to get at what might be causing you confusion: I suspect you're thinking, how come this thing has run for over a century, but I need to get a new car battery every few years? The article on the bell says the batteries are probably Zamboni piles, and if you read that article you'll see that their current output is in the realm of nanoamperes. Zamboni piles are primary (non-rechargeable) cells, but their chemistry appears pretty stable, and the amount of power the bell uses is very tiny. But it would take a huge number of Zamboni piles connected in series to run something like a flashlight, which is why we don't use them for much. --47.146.63.87 (talk) 23:10, 27 January 2020 (UTC)
 * One could run a flashlight from just a few layers of a Zamboni pile - however the area needed would need huge discs. Andy Dingley (talk) 23:15, 27 January 2020 (UTC)
 * Ah, thanks for the correction. And of course they're not rechargeable, which makes them not terribly practical for most applications, though the article states they did find a few uses until recently. --47.146.63.87 (talk) 02:54, 30 January 2020 (UTC)
 * I have a couple here from 1st generation military night vision goggles. The photomultiplier tubes need a 1kV or so to power them, but with a tiny current, so Zambonis were ideal. My 1960s NV sets had already switched to electronic PSUs instead. Andy Dingley (talk) 02:27, 31 January 2020 (UTC)