Wikipedia:Reference desk/Archives/Science/2016 April 6

= April 6 =

That automatic camera timer
I don't know what it's called. You set it for 10 seconds and run back into the frame to be in the shot.

Is there a camera that does that but then keeps taking pictures every 5 seconds or so for a while?

Anna Frodesiak (talk) 03:08, 6 April 2016 (UTC)
 * Self timer. Now with digital cameras, I can't imagine any type of time-delay or timing pattern of multiple images can't be accomplished. But I'm not familiar with commercial cameras in general, so I have no idea what's available (vs what could be programmed on a smartphone or other custom device). DMacks (talk) 03:17, 6 April 2016 (UTC)


 * Hi DMacks! Thanks for the feedback. But now I am totally confused. :) I don't know the difference between a digital camera, a commercial camera, and a custom device. As for "accomplished", I think it either has the setting or not. Cheers. :) Anna Frodesiak (talk) 03:31, 6 April 2016 (UTC)
 * I read "a camera" to mean a preconstructed object whose primary purpose was to take still protographs (the thing we called a "camera" that used to have a roll or disc of film but more recently instead uses digital processing...not "the camera feature now seemingly present in every portable device, phone, and computer). A digital camera has a lot of on-board embedded processing available, more than just the mechanics of a button connected to a shutter. Once you have electronic control and don't need to do anything physical internally to "take a picture", you can have an electronic controller fire the "take a picture" electronic actions any time using some circuit. The old cameras had a fixed 10-second timer, but with a pure electrical system, one can have any one-time or repeated timing pattern one likes by using some custom-designed circuit or bit of software programming. So "it can be done". But I don't know of "a camera" that actually does it. But using a more general piece of hardware that happens to be able to take photographs, (for example, "a phone that has a camera in it"), it's easy to write a program that uses that camera function (again, on any arbitrary schedule). It's easier on "a smartphone with a camera" than with "a camera object" because the actual programming interface is available (anyone can write an app), instead of only having the few buttons and built-in software or interfaces that a camera-object's manufacturer decides to make available. As others have noted below, there actually are camera-objects that have this feature already and/or make the interfaces available for third-party controllers. DMacks (talk) 04:55, 6 April 2016 (UTC)
 * intervalometer is the device that you are looking for.
 * Not quite what you are after but some Canon DSLR cameras have wifi (I have a 6D) and you can get an iphone app which lets you use your phone to remotely trigger the shutter. It's really awesome, you can even see the camera's viewfinder on your phone and change the settings. The only thing you really have to do at the camera is "frame" the shot (you can't "move" the camera with the phone), then you can do the rest with your phone. When I want to take a group shot, I just hold my phone behind my back, or behind someone/something else and trigger the shutter a bunch of times. Vespine (talk) 04:02, 6 April 2016 (UTC)
 * Also, any of the "more expensive" remote shutter trigger probably has the options you need, for example this canon remote control does everything you've asked, from a different site the unit's features include a self-timer, long-exposure timer, interval timer and the option to set the number of shots in a sequence. . Vespine (talk) 04:06, 6 April 2016 (UTC)

Holy moly. I seem to always ask questions that draw very complicated answers. I just noticed that all cameras seem to have a self timer that takes just one shot and then you have to walk up to it and set it again. A bit silly, if you ask me. Multiple shot capability should be standard on all cameras. I imagine it would be very well received and quite a selling point. And I-phones don't seem to have any self timer at all. Thank you all kindly for the thoughtful replies. I am sorry to ask such questions. Anna Frodesiak (talk) 06:33, 6 April 2016 (UTC)


 * Most digital cameras also have an option to record video, although often at reduced resolution, but that might work in some cases. Of course, the first few seconds will be you starting it and running back to the group to be photographed, and the last few seconds will be the reverse, but you can edit that out later.  You can also pull stills out of the video later. StuRat (talk) 06:57, 6 April 2016 (UTC)


 * Thanks, StuRat. I guess that would be sort of okay. Now, if your camera could do multiple timed images, say, every 5 seconds, wouldn't that be useful and fun? And wouldn't you get lots of great photos out of it? :) Anna Frodesiak (talk) 07:02, 6 April 2016 (UTC)


 * The problem with that is that you would need to hold your pose for a long time, not blinking, etc. They would need to add some type of audio or visual cue to tell people when the next frame will be taken, in order to avoid that issue.  The remote trigger also solves that problem.  StuRat (talk) 07:05, 6 April 2016 (UTC)


 * Why hold the pose? Everyone would have 5 seconds to get it together and then the little light or beep would go and zam, another photo. I think it would be bags of fun and produce a choice of 5 or 10 great pics. So, if they had it, would you use it? Anna Frodesiak (talk) 07:11, 6 April 2016 (UTC)


 * No, it would be too restrictive for me. Every 5 seconds we would have to get into a good pose, be careful not to blink, etc.  More likely most of the shots would be bad because somebody would be moving, not looking at the camera, have their eyes shut, be talking, etc.  Of course, there is such a thing as "candids", where you take pictures without posing.  But those tend to generate a large volume of pics with only a few being worth keeping. StuRat (talk) 07:32, 6 April 2016 (UTC)
 * StuRat, I think you would love it. Maybe every ten seconds with a light just before. After several photos everyone would start to crack up and the photos would get really good. Anna Frodesiak (talk) 08:02, 6 April 2016 (UTC)


 * Note that professional photographers photographing subjects like models used to have a setting that would take a pic, say, every second. They held onto the camera while using this setting, though.  As I mentioned above, this did generate a large volume of pics, and only a few were "keepers". StuRat (talk) 07:36, 6 April 2016 (UTC)


 * If your camera does support taking photos at sufficient intervals (at 5 seconds apart or whatever) and of sufficient quantity, then you could just start taking photos and delete the ones at the beginning. The only issue would be that there may not be any indicator before each photo. Nil Einne (talk) 07:40, 6 April 2016 (UTC)
 * Every second, sure. But that's that "...work with me baby, come on, feel it..." type of thing. So, sure there would be hundreds with a few keepers.


 * That whole idea of setting the camera to 10 seconds and rushing in front to join the others for a single snap seems very old fashioned. Surely an option string of 10 photos with 10 seconds between would be an improvement. Anna Frodesiak (talk) 08:02, 6 April 2016 (UTC)
 * I'm fairly sure there's quite a few cameras which do allow setting the interval. After all, it's used for time lapse photography although 5 seconds is a bit short for most time lapse. Anyway in terms of your later point AFAIK the most common option nowadays is that the camera will take a burst of several photos after the timer with the possible ability to set the number of photos but not an interval (it's intended to be a burst not time lapse) with the hope that one of them will be good despite people blinking etc. If this doesn't work it'll probably be possible to combine different photos so it's also useful in that way. I think your specific option is less common because if you're going to take a seperate shot most people would prefer to set it up first. Nil Einne (talk) 08:42, 6 April 2016 (UTC)
 * Okay, that makes sense. But set it up first and someone has their eyes closed and you have to run back and set the timer again. That is what this was all about. Also, that smartphone burst thing seems to make too many photos. Many thanks for answering yet another annoying Anna question. :) Anna Frodesiak (talk) 08:47, 6 April 2016 (UTC)

Aside: I'm typing and suddenl "y" is a "z" and my full colon is an "E" with two dots on top. Why? I'm typing this in a notepad and pasting it here. Help! :) Anna Frodesiak (talk) 07:48, 6 April 2016 (UTC)


 * Never mind. Someone in IRC helped me with that. Anna Frodesiak (talk) 08:00, 6 April 2016 (UTC)


 * The OP did not state which model of camera they have. CHDK concentrates mainly on Cannon but other brands are being worked upon. It give you full control over the cameras firmware. It included setting time lapse and multiple images. It will even calculate the hypo-focal distance like professionals do,  to give a better focused group shot. Warning. It requires one knowing how to switch on a computer,  down-load, instal a program and to own a digital camera.--Aspro (talk) 12:08, 6 April 2016 (UTC)


 * This Youtube clip describes how to down load, instal and select time laps for whatever intervals you so desire.   Canon CHDK Hack Tutorial: RAW, HDR, and Time Lapse Does a lot else as well. Keep it on a spare  SD memory card until one gets used to all the options. No sensible Canon camera would want its owner to not to have one.--Aspro (talk) 12:51, 6 April 2016 (UTC)

.
 * Other models are available! I have a digital Pentax (medium price range - not a professional model). I can adjust the settings of the timer such that the shutter can remain open for as long as I want.  I can set it to do this multiple times, with each exposure made after an interval which I also set.  So, I can set the camera to open the shutter for 20 secs, every 1-minute, and continue to do this for 3 hours. This is how we get those wonderful pictures of stars appearing to circle in the sky called Star trails. DrChrissy (talk) 13:46, 6 April 2016 (UTC)


 * The answer is you can set the timer on a 2 to 10 second interval on a modern DSL camera like e.g. Canon 1200D.--TMCk (talk) 14:36, 6 April 2016 (UTC)

Thank you thank you thank you! This is exactly what I'm after. I've been using this horrid Sony Cyber-shot DSC-T700 and am trying to persuade family to let me get a better one. Every time there is a timer group photo, I have to run back after each shot and set it again because someone had to be a joker. This interval thing would be poifect! I will look into the cameras you've suggested. Many, many thanks, DrChrissy, TMCk, and everyone else too!! P.S. Lovely Star trails! Anna Frodesiak (talk) 23:09, 6 April 2016 (UTC)
 * Anna, I did not mention that my camera also has a remote control device. So, I can put the camera on a table/tripod, focus and frame it on my friends, then turn on the remote control function on the camera.  I can then rejoin the group, pose, then press the button on the remote control device and it takes our group photo.  I can do this for as long as I want without having to return to the camera.  I can also set a delay (e.g 2 secs) so that I have time to hide the remote control in my hand or behind my back - otherwise all the photos have me pointing a small plastic device at the camera!  Happy snapping. DrChrissy (talk) 23:17, 6 April 2016 (UTC)


 * Yeah, this kind of thing is pretty standard on higher-end cameras. I have an almost decade-old Canon that has "continuous shot" and remote control. The tl;dr answer to the original question is that you need to look at professional or "enthusiast" cameras, not the cheap low-end ones. --71.110.8.102 (talk) 19:29, 7 April 2016 (UTC)
 * I'm glad to hear it's standard on some cameras and hope it becomes standard on all. After all, it's programming, so no extra cost really, therefore no real reason to omit the feature from cheapos. Thank you for the feedback. Anna Frodesiak (talk) 21:35, 7 April 2016 (UTC)
 * Hi DrChrissy. A remote control, yes. I had one of those on a Sony Handicam. I still think auto-timer offering 5 shots at intervals would be liked by customers. Cheers. Anna Frodesiak (talk) 21:35, 7 April 2016 (UTC)


 * Happy to help. BTW, if you want to check a camera's more detailed features (like the timer modes), check the model specific user manual online ;) --TMCk (talk) 00:08, 7 April 2016 (UTC)
 * Good suggestion, TMCk. Thank you. I will try. I doubt they will have an advanced search feature to allow me to find models with that. I will probably end up going through camera descriptions one by one. Anna Frodesiak (talk) 21:35, 7 April 2016 (UTC)

Harvest energy of downwards escalator
I'm getting very interested in escalators (because I currently spend about a quarter of an hour a day on escalators in the Kyiv metro system). [I was amazed to learn from the escalator article that the term to 'escalate', as in wars etc., comes from the machine.]

The article mentions that most escalators use AC motors. I wonder if a downward escalator could be so crowded - say with two people on every step - that their weight exceeded the friction and the escalator would have to be braked or governed? And if this were the case, would it be efficient to couple its mechanism to the upward escalator?

Hayttom (talk) 12:48, 6 April 2016 (UTC)


 * Hey, Haytttom, interesting question! It seems the answer is "yes, some escalators use something akin to regenerative braking." Here is a scholarly article on energy efficiency in escalators (and elevators), and mentions regenerative braking in a few places, as well as things like optimizing counterweight. They claim that highly efficient escalators (and elevators) can use 80% less than their old-fashioned un-optimized counterparts. This paper is more about metro systems as a whole, but does have some interesting stuff about how escalators fit in to the big picture. Finally the E4 project  has a mission of studying and improving efficiency in lifts and escalators, though their web presence is a bit thin. SemanticMantis (talk) 14:12, 6 April 2016 (UTC)


 * I've never felt the need for downward escalators to begin with, as I only get tired walking up stairs, not down. But, I understand that architects like the symmetric look of one up and one down escalator.  I always thought the down escalator could work without a motor, just using the weight of the passengers and a mechanism like a thick fluid to limit the speed.  This would mean it would stop when nobody was on it, and small people might not be heavy enough to overcome friction and move it, but then they could just walk down.  Can anyone put some numbers on this, and let us know what kind of frictional forces we must overcome ? StuRat (talk) 16:09, 6 April 2016 (UTC)


 * I can't see any easy way to use a counterweight on an escalator. I'd have thought it should be possible to link an up escalator with a down escalator and so only have to cope with the difference in weight between people going up and down. I guess regenerative braking is easier though. Dmcq (talk) 17:37, 6 April 2016 (UTC)
 * Sorry, my mistake. I've added "and elevators" to my post to clarify that I (and the article I linked) was talking about both. SemanticMantis (talk) 18:35, 6 April 2016 (UTC)

Water ballast cable cars (→de:Wasserballastbahn) operate similar to Your idea and have less friction per passengers than current escallators. The Steffturbine has a high efficiency and might fit it when using people instead of water. Elevators use a counterweight. The oversized and filled counterweight makes the passive system of a water ballast cable car operate. -- Hans Haase (有问题吗) 08:31, 7 April 2016 (UTC)


 * Thanks, everybody! Hayttom (talk) 03:35, 8 April 2016 (UTC)

Wind and solar power
Can wind and solar power combined ever match the power output of current fossil fuels such as oil and natural gas, to power large cities such as Los Angeles or London?--WaltCip (talk) 13:59, 6 April 2016 (UTC)
 * Read Renewable energy in Germany and see if it leads you to any conclusions. -- Jayron 32 14:34, 6 April 2016 (UTC)
 * Renewable energy in Denmark also has some interesting data. -- Jayron 32 14:35, 6 April 2016 (UTC)
 * This is excellent reading. Thanks.--WaltCip (talk) 14:42, 6 April 2016 (UTC)


 * There is far more solar energy available than would be needed to power our cities. In some areas, there is also sufficient potential wind power.  To fully replace fossil fuels, these technologies would need to be combined with some form of large-scale energy storage technology to provide power at times when the sun doesn't shine and wind doesn't blow.  There is no reason humanity couldn't go 100% solar and wind, but right now it would cost more than fossil fuels which is often the limiting factor unless adoption is driven by government mandates or incentives.  Solar cells are getting cheaper, but still cost more than fossil fuels in most cases.  Wind turbines can be cost competitive with fossil fuels in areas with consistent strong winds but less so in areas with intermittent or weak winds.  Large scale energy storage is also still pretty expensive in most areas but can be done.  Dragons flight (talk) 14:54, 6 April 2016 (UTC)
 * This site has an interesting map of the land area required using solar alone (not counting wind, hydro, geothermal). Rmhermen (talk) 15:18, 6 April 2016 (UTC)


 * The trouble with the "X costs more than Y" argument is that we very often fail to include all of the costs. It's quite possible that the cost to construct a coal power station and to mine the coal to fuel it for (say) 50 years will be less than to construct and operate a wind power plant with the same capacity over the same period.  But if you include a fair share of the cost of shoring up ocean wall defenses due to sea level rise due to the coal plant's excessive CO2 output - then the economic argument gets shakier.  But how should we price the loss of the polar bears - or the impact of all of the ash mounds left by the coal plant - or the loss of human life due to the dangers of coal mine accidents?  So economic arguments only get you so far.  However, there is great difficulty with using this extended economic argument as consequence of the way human societies have formed.  If (say) mainland China doesn't have much issue with coastal flooding, then it feels a lower price for coal power plants than an island nation like Indonesia - where sea level rise is a critical factor in their survival.  But each country makes the decision on how to price and regulate coal power plants, even though the global climate is something that we all share.


 * Energy storage is certainly a big issue with many kinds of renewable sources - but those costs can be mitigated by beefing up our energy transmission capabilities. Sure, the amount of wind available in one particular area may be intermittent and somewhat random - but the average amount of wind available over an entire country, or an entire continent, should be much more predictable.  So if you can efficiently move energy around, you can average over space instead of using storage systems and averaging over time.  Averaging over domains (solar/wind/tidal/geothermal) gets you an even more predictable output.


 * SteveBaker (talk) 15:24, 6 April 2016 (UTC)


 * Not to derail the topic, but it bothers me that China is able to get away with a lot of environmental catastrophes (the smog and traffic in Beijing are rated as among the worst in the world) and not be held accountable for them the same way other developed nations are.--WaltCip (talk) 15:50, 6 April 2016 (UTC)


 * They are still considered a "developing" nation, but the pollution is becoming a concern to them, too, at least the obvious pollution, like smog. London and New York City had their periods of horrible pollution, too.  It's a variation on tombstone mentality, where they weren't willing to do anything about pollution until it affected them personally. StuRat (talk) 16:17, 6 April 2016 (UTC)


 * At ~$8,000 per capita, the GDP of China is still below the world average (~$10,000) and far below the traditional developed countries (US, Europe, etc.; $30k-50k).  In terms of pollution, China situation's today is reminiscent of the US situation in the 1960s when after a long industrial expansion pollution had become widespread and a populist political backlash was starting to drive reforms.  If they follow the American example, we might expect to see dramatic improvements in China's environmental situation over the next 10-20 years.   For example, the US cut regulated particulate emissions in half during the first decade after the passage of the 1970 Clean Air Act.  Dragons flight (talk) 19:10, 6 April 2016 (UTC)


 * If you're just talking about haze or air pollution in cities, it's sort of weird to single out China as is often done. Sure China is terrible, but most data shows Indian cities tend to be worse on average e.g.  although it's obviously difficult to make comparisons given the varying ways measurements are done, data is made available etc . Still at a minimum what data there is suggest there's no reason to think of the situation in Chinese cities as some sort of extreme barometer, at a minimum both Chinese and Indian cities should be considered and possibly others . (Of course air pollution in cities can depend not just on pollutants but weather the Asian brown cloud article sort of touches on that and while local pollution is generally a factor, as the Southeast Asian haze has shown so to can pollution from neighbours.) In terms of overall environmental issues, to give an example India is worse than China in the Environmental Performance Index . Economically China is obviously at a far greater level of development which shows in things like the higher levels of GHG (although still far less per capita than places like the US, UK, Australia and NZ), however with Modi's make in India and other campaigns there's fair concern what this means for the future and whether India will deal with it better or worse than China   . As the other commentators have touched on and my comment did as well to some extent, a key factor the fact is that China or India both of which are still developing nations by most definitions, are at a significant different level of development from whatever developed countries you're thinking of. Most of the developed countries did similar things or worse (albeit since they are smaller often on a smaller scale) at some stage of their development. The "learn from us" mantra is all fine and well, but it doesn't necessarily resonate with government or citizenry when it's likely to mean a significantly less or slower development and as plenty of examples have shown it's not like developed countries are particularly willing to pay to protect the environment during other countries development (and for large countries like India or China, they probably couldn't really afford to make that big a dent anyway). Or to put it a different way, hold to account at what stage? While there are some grumblings about historic issues, there isn't really much of a serious suggestion to hold developed countries to account for their historic environmental issues (except perhaps from their own citizens). In a number of ways, particularly in regards to deforestation and GHG emissions, developing countries now are actually normally facing more strigent expectations than the developed countries faced during their development. Nil Einne (talk) 13:15, 7 April 2016 (UTC)


 * The news reports that India is much worse than China are basically based on a lack of information. As of 2015, China only provided WHO with PM10 data and only for select cities as of 2010.  Since 2013, China has been monitoring more cities and collecting the more health-relevant PM2.5 data but those figures have not yet found their way to the WHO.  If one looks at the PM2.5 data, China and India are much more similar.  China should actually occupy about half the slots on the top-25 most polluted cites, and go as high as #4 on the list.  WHO is expected to release an updated list later this year.  China and India are both major problems, though for different reasons.  China's biggest problem is coal, whereas India has a huge biomass burning problem.   Dragons flight (talk) 14:07, 7 April 2016 (UTC)


 * Regarding including all the costs. This is known as life-cycle assessment and is related to Whole-life cost and impact assessment. Specifically addressing these ideas with respect sustainability issues, here is a nice overview of life cycle analysis from the Illinois Sustainable Technology Center. SemanticMantis (talk) 18:19, 6 April 2016 (UTC)


 * There is no good or efficient manner to store large quantities of energy...and the ability to do so isn't on the horizon...so when wind doesn't blow or sun doesn't shine...this is actually a major problem for wind and solar..68.48.241.158 (talk) 18:36, 6 April 2016 (UTC)


 * Isn't pumping water from a low reservoir to a high reservoir a reasonably efficient way to store large quantities of energy ? StuRat (talk) 18:40, 6 April 2016 (UTC)


 * Doesn't the energy spent from pumping water from a low elevation to a high one negate the potential energy stored as a result?--WaltCip (talk) 18:52, 6 April 2016 (UTC)


 * Walt, it's not a method of creating energy, just of storing energy from some other source. For example, solar panels that create too much electricity when the Sun is up and none at night.  During the day, the excess would be used to pump water to the high reservoir, while at night the water falling from that height would power turbines, like in conventional hydroelectric power plants/dams. StuRat (talk) 01:01, 7 April 2016 (UTC)


 * It costs energy, but that doesn't negate the utility of the idea. Nothing is free, and especially not energy storage. The costs are often worth it. Pumped-storage_hydroelectricity is our article that StuRat should have linked if he's going to bother talking about this stuff on the reference desk. I know that we have an article on that and how to find that article but not everyone does, so it's just common courtesy to provide wikilinks if we want to actually help people at the reference desk. Okinawa_Yanbaru_Seawater_Pumped_Storage_Power_Station is a good example of pumped-water energy storage, and there are even schemes to store energy by pushing rail cars full of gravel up hills .  Energy storage and List_of_energy_storage_projects are also highly relevant to this thread. SemanticMantis (talk) 19:09, 6 April 2016 (UTC)


 * In practice, usually 70-75% efficient round-trip. So everything else being equal pumped-hydro will probably make the electricity at least ~35% more expensive.  However, since the wholesale cost of electricity often already varies by more than 100% due to time-of-day load variations, this is probably acceptable.  The biggest limitation of pumped hydro storage is that it is only easy to implement in areas with existing reservoirs or where the terrain makes new reservoirs relatively easy to construct.  Other technologies, e.g. NaS batteries, compressed air, flywheel energy storage, etc., will probably make more sense in terrains that don't readily support pumped hydro.  These things are entirely possible if one is willing to pay the associated costs.  Dragons flight (talk) 19:10, 6 April 2016 (UTC)
 * There's been some discussion about electric cars as a form of distributed storage. The cars get charged up at night when there tends to be a surplus of generating capacity -- sometimes utilities literally give away nighttime electricity to maintain their base generation load. Then the cars are driven during the daytime. Shock Brigade Harvester Boris (talk) 00:45, 7 April 2016 (UTC)
 * I strongly recommend reading, and understanding, the ebook/website linked to from here. Basic conclusion is that for the UK you need nukes if you are trying to actually reduce CO2 output. In my opinion Renewables are useful without extra storage up until X % contribution to generating capacity, X is certainly not a simple number to calculate, 20 might be a place to start, to be generous. The problem with storage is all the good hydro sites have gone, and nothing else is cost effective at current base load prices. Greglocock (talk) 18:45, 6 April 2016 (UTC)


 * if you're not afraid of nuclear power generation than "renewables" are a complete and utter waste of time, money, and effort....but perhaps nuclear power is indeed something to be afraid of....(if your receiving govt subsidies to run your solar panel business, than "renewables" are wonderful)...68.48.241.158 (talk) 21:05, 6 April 2016 (UTC)


 * Not a complete waste of time, just niche markets. If you live far from the grid, and have lots of sunlight and/or wind, then they make perfectly good sense for you, even without subsidies. StuRat (talk) 21:17, 6 April 2016 (UTC)


 * No nuclear power station has ever been economically viable without massive public subsidies, including limits to the liability of owners for accidents and radioactive waste. And even assuming that nuclear power can be made "safe" in the first world (although Fukushima is not a good sign), it does not scale out. Who wants nuclear power plants in Nigeria, Libya, Iran or Somalia? --Stephan Schulz (talk) 21:23, 6 April 2016 (UTC)


 * the political/regulatory cost have made them economically difficult at least in USA...but in and of themselves there's nothing that even comes close...a single plant can power half a million home, night/day/wind/no wind....there's nothing that comes close....renewables aren't even in the conversation, particularly since you can't count on them at any given time....68.48.241.158 (talk) 21:31, 6 April 2016 (UTC)


 * Some forms of renewable energy are available 24/7, like geothermal. Of course, that only works in certain places. StuRat (talk) 21:33, 6 April 2016 (UTC)


 * Solar power towers using molten salts, heat up more than needed. So there's capacity to drive turbines over night. Using the kalina cycle, can make even more efficient. -- Hans Haase (有问题吗) 07:56, 7 April 2016 (UTC)


 * I think StS has touched on two key points. Particularly when I lived in Malaysia I was often somewhat favourable to Indonesia or other such countries when it came to complaints on environmental or other such issues from people from developed countries (generally the West). But I don't think there was ever a point of time when I was favourable to Nuclear power in Indonesia and I don't think this attitude is uncommon among Malaysians or other regional neighbours. (The other environmental issue which annoys most would be the Southeast Asian haze, although companies from neighbours like Malaysia are probably a contributing factor to the issues in Indonesia.) In fact, I'm not really sure if I ever even trusted Malaysia to use nuclear power, and I definitely don't now. Nil Einne (talk) 13:48, 7 April 2016 (UTC)

Does kosher/halal beef taste different due to drainage of blood?
An older person I know has been having a lot of trouble appreciating steak and other meat lately. She keeps complaining it all has a "liver" flavor. From a master's thesis I found on the topic there is some indication that hemoglobin level in the meat matters, as it is a source of free iron that causes degradation while cooking (cooking temperature is also a factor, and various other things). It cites this for that, which I haven't accessed in full, that talks about liver flavors being a combination of metallic and fishy taste; I suppose the source must have some discussion.

Anyway, I just want to back up, go in the front door here and ask: are people aware of any evidence that kosher/halal meat, from which blood is drained as thoroughly as possible, has a different flavor of any kind from other meat? Of course, searching online finds people who say yes - in the past I had assumed this was boosterism, and a double-blind test with a sufficient sample size wouldn't find people able to tell. But finding real data is tricky on this.

FWIW, I already suggested she might try it and see - it can't hurt, unless you happen to be a cow. :) But I am just wondering if there's any science on it. Wnt (talk) 14:01, 6 April 2016 (UTC)


 * I'm guessing you searched google scholar for longer than the 4 minutes I did? I didn't find any proper controlled experiments either. I did find one potential lead though: I would try to contact these folks at the Halal Products Research Institute. Seems they do perform/fund real science published in good journals. If anyone knows about the existence of the studies you're looking for, I bet they do. SemanticMantis (talk) 14:18, 6 April 2016 (UTC)


 * And to approach from another tack: what about cortisol? Here is an article from The Atlantic discussing how animals with higher cortisol levels and less humane treatment might taste worse, and here  is a scientific article talking about Malaysian Halal standards, including maximum cortisol levels. Still no good studies on taste, but I think cortisol must be a conceptually viable route to different taste in halal/kosher meats. SemanticMantis (talk) 14:25, 6 April 2016 (UTC)


 * We have an article on the PSE meat referenced. But it's a good search term - with it I found  which makes all kinds of totally unexpected statements about kosher meat.  Their results are that the loss of blood is actually not any larger in kosher meat.  But they find the meat loses less water, is tenderer, is a different color than the conventional meat.  So kosher treatment seems to make much more difference than I'd imagined, even while not having the effect I expected. Wnt (talk) 14:55, 6 April 2016 (UTC)


 * Before considering the possibly different flavour of the meat, you might consider the effect of age on the human sense of taste. My mother has been complaining for a long time that the food doesn't taste as good now as it used to. To me it all seems fine - and I think the fact of her being 100 may be significant. 217.44.50.87 (talk) 15:44, 6 April 2016 (UTC)


 * Many foods really don't taste as good as they used to, because they have bred them to grow quickly, at the expense of flavor and nutrition. StuRat (talk) 16:20, 6 April 2016 (UTC)


 * Do you have a source that confirms how growth rate of foodstuffs affects flavor and nutrition? 91.155.193.199 (talk) 00:44, 7 April 2016 (UTC)


 * Here you go: . The book referred to at that link is The Dorito Effect: The Surprising New Truth about Food and Flavor. StuRat (talk) 04:29, 7 April 2016 (UTC)


 * Oh, I'm sure all sorts of individual factors play a role, but I was focusing for this purpose on what can be done to the meat rather than the taster. Wnt (talk) 17:25, 6 April 2016 (UTC)


 * Conventional livestock slaughter is usually a 2-stage procedure. The animal is first rendered unconscious by, e.g. a stun gun.  The animal is then immediately killed, usually by exsanguination.  My thought here is that the removal of blood is likely to be very similar to the kosher and halal methods, and therefore unlikely to have any influence on taste.  To WNT, people of the Jewish faith do not eat pork, so there is no such thing as kosher pork and PSE is therefore not an issue - I think. DrChrissy (talk) 15:47, 6 April 2016 (UTC)


 * The first line of that article says "beef and poultry" also. But I think it's not technically an issue for another reason, which is that they say it's only 3% of meat, or anyway, not more than 10.  Nonetheless, the "exudative" is reminiscent of the differences in water loss during cooking in the study I cited above, so it might be the extreme case of a broader phenomenon.  (but I don't know that) Wnt (talk) 17:25, 6 April 2016 (UTC)


 * Suggestion: If she doesn't care for the taste of meat any more, and we know meat is unhealthy anyway, maybe it's time to explore more vegetarian options. Might keep her alive and healthy longer, too.  Or she can avoid red meat and stick with things like fish and chicken, if she still likes those flavors.  StuRat (talk) 17:38, 6 April 2016 (UTC)


 * I tried to go that direction in the conversation, but didn't get anywhere; besides, I don't want to stray too far from the question of whether kosher/halal tastes different, which is more answerable. Wnt (talk) 18:57, 6 April 2016 (UTC)


 * Ah a question about food, one of my most favourite topics. Yes your taste buds may be getting less sensitive but I think your asking about why the meat itself doesn’t taste like it used to. The whole reason for bleeding meat, was it kept longer (and did not develop those off flavours) before the days of refrigeration. It was also hung for 4 or more days for rigour-mortis to pass. These days the cow walks in to the abattoir one morning and is vacuum packed by lunch time. The vacuum packed meat today is not bled and undergoes what is euphemistically referred to a 'wet curing' because it is more profitable for the food (?) industry. Find a family butcher that can supply properly hung meat (or order it over the internet). Ask for 'Dry Cured Aged' meat. If they can't supply AGED  then dry cure yourself in the fridge.  The link give some directions: How to Dry-Age Beef at Home Finally, always roast at a very low temperature (like Grandma used to do). The British award wining chef Heston Blumenthal  gives guidance on the best temperatures and cooking times for most common cuts but you will have to google it. --Aspro (talk) 21:22, 6 April 2016 (UTC)


 * I have a beef about that advice to cook at a low temperature. While somebody in their prime could fight off any bloody food poisoning, the aged are at more risk, so all meat should be cooked thoroughly. StuRat (talk) 21:27, 6 April 2016 (UTC)


 * Thorough and cooking temperatures are two different things.  Its like the pasteurisation of milk. 161°F (71.7°C) for 15 sec or 145°F (62.8°C) for 30 minutes.  A proper low temperature meat roast takes 4 to 5 hours to bring out the full flavour (for some meats like fowl it need to be higher -so check). Otherwise we would not be here today, because our grandmother would have poisoned everyone. --Aspro (talk) 21:53, 6 April 2016 (UTC)


 * Yes e.g. beef is safe at 145°F internal temperature . You could in principle get it there by setting your oven to 146°F, which would indeed be a very low cooking temperature (this is not recommended as a cooking technique, but it illustrates the point). We also have a whole article on Low-temperature_cooking. But none of this is really relevant to the OP's question, it is rather relevant to Stu's shoot-from-the-hip comments on topics with which he is unfamiliar. SemanticMantis (talk) 21:59, 6 April 2016 (UTC)


 * I would (have) gone lower for beef to 122 °F.  Of cause this is assuming one uses a meat thermometer and calibrate it – (dip in boiling water and add a few degs for safety). Some ovens are better than others, so don't  rely on you ovens temperature gauge.. Think this is New River Restruant's philosphy as well. And they give cooking times and show photographs of the results. --Aspro (talk) 22:33, 6 April 2016 (UTC)


 * At that low of a cooking temperature the food is indeed unsafe, just as I had warned. StuRat (talk) 22:42, 6 April 2016 (UTC)


 * Citation needed.--Aspro (talk) 23:23, 6 April 2016 (UTC)


 * The ref was provided by SemanticMantis, right before your last post. See page 4. StuRat (talk) 00:47, 7 April 2016 (UTC)


 * Well your "warning" was useless because you gave no refs and not even any numbers! You asserted that cooking at low temps is unsafe. That is patently false. Millions of people cook at low temps safely every day. It is true that there is some relation between temperature and food safety of meat. It is true that some temperatures are considered too low by safety authorities. It is true that all this can be clarified with a simple reference, which you could have given if you spent 30 6 seconds googling (I timed it) instead of typing your first vague and unclear reaction. 14:50, 7 April 2016 (UTC)


 * Don't think SM signed his last comment above. Anyway Stew Stu, page 4 does not give the cooking times. Also, the Serving Temperature refers to the recommended safe Serving Temperature (is that tautological ?). In restaurants and buffets, the  food is already cooked but  often displayed for 'long periods' in areas where cold air currents can cool some it down  to  levels were bacteria can multiply very fast.   I am not denying the fact that, given the right conditions they exhibit exponential growth. So 'cooked' food 'on display' needs to be kept at higher temperatures. As an example from the other end: Consider the fridges in commercial restaurants – modern hygiene standards require them to be 'fan assisted' because in a busy restaurant the doors are constantly being opened and shut – much like an oven door. They need fans to quickly bring the temp back down in a way that is not considered necessary for domestic fridges. So for commercial offerings where the food is not to be consumed immediately (within approx 15 mins)  – other hygiene guidelines apply. So, for those reasons, page four is not a valid reference to 'safe cooking' temperatures.--Aspro (talk) 16:38, 7 April 2016 (UTC)


 * It appears to be a reliable source (the USDA). As stated "Cook foods to the recommended safe minimum internal temperatures listed below", and 145°F was the min listed for beef roast.  Your suggestion to cook at 122°F is never going to get the interior temperature above 122°F (do you need a source to prove this, too ?).  And the fact that food can be unsafe in other ways in no ways cancels my point that cooking at 122°F is unsafe.


 * And my stating that there is some temperature too low to cook food safely didn't need a ref precisely because I didn't assign a number to it. A specific number would require a source, but the general statement is so patently obvious that it does not.  Meanwhile, you ignored the ref provided and instead gave dangerous food prep advice that you would have known not to give had you found a ref, or at least read the ref provided by SM.  StuRat (talk) 17:06, 7 April 2016 (UTC)


 * Yes. I did read though SemanticMantis's reference and took delight from it. But going back to the OP's question . I was pointing out that if he wants to rediscover  the full flavour of yesteryear, then try  s-l-o-w  roasting -which takes time and so kills the bacteria in the process. I also  made the comparison with the different  times for full  pasteurizing milk vis temperature. The need for a calibrated meat thermometer. Guidelines are advised (not set in concrete) for the common Joe (or more probably Jane). I also made reference to Heston Blumenthal. Did 'you' read that reference? “He advocates scientific understanding in cooking, for which he has been awarded honorary degrees from Reading, Bristol and London universities and made a Fellow of the Royal Society of Chemistry. He is a pioneer of multisensory cooking, foodpairing and flavour encapsulation.” So not exactly a naïve amateur,  wouldn't you agree? Here is one of his recipes for slow-roasted rib of beef. It states for 'rare' - cook at 50ºC . Being old fashioned, that means to me 122º F  -as I stated above. If you want an even better reference – I can give one of the best of all. I and my forbears thrived on s-l-o-w roasted joints every Sunday, with fruit pie and home-made custard (now commonly called crème brûlée, made without pasteurized eggs – oh shock and horror) for deserts!--Aspro (talk) 18:56, 7 April 2016 (UTC)


 * An honorary degree is of no value in establishing credibility. But, even if I accept him as an expert on food taste, that in no way makes him an expert on food safety.  Some people do prefer rare, or even raw, meats, fish, eggs, etc., but those do carry significant health risks, especially for the elderly and otherwise immune-impaired.  Restaurant menus in the US state as much (at least here in Michigan they do). StuRat (talk) 03:10, 8 April 2016 (UTC)


 * Pasteurized eggs? DrChrissy (talk) 19:54, 7 April 2016 (UTC)


 * Yes, restaurants now are requested by some health and safety Jobsworths to buy safe, quality assured, pasteurized eggs in cartons. And please no jokes about Cleopatra asking if she wanted her bath of asses milk to be pasteurized – when she only wanted it  up to her chin. . I like eating, so I make dam sure that I get invited into the kitchens as often as possible to see what goes on behind the scenes.  A lot of restaurants look great, from the clientele point of view, but some, back  stage are food-poisoning-outbreaks waiting to happen. There is nothing difficult or underhanded in this approach. A  good proprietor is only too happy that you take an interest. His staff like it too – they are getting recognition for once,  by someone that appreciates their skills and long hours of toil  in a hot sweaty kitchen.  If one doesn't ask, one doesn't get to see. It also makes life more interesting and of course, I always have my camera ready. Its a win-win.--Aspro (talk) 21:09, 7 April 2016 (UTC)
 * Well I learn something every day here. Never heard of pasteurised eggs before. Here in the UK, producers are not allowed to even wash eggs in water as it is feared this can can dissolve faecal contaminants through the shell and into the egg contents.  Just as a slight aside, here in the UK there seems to be a growing demand for raw milk (i.e. non-pasturised).  Sounds like a TB problem waiting to happen and a further excuse for badger hunting. DrChrissy (talk) 21:49, 7 April 2016 (UTC)


 * As an aside also: Raw milk (which comes in green top bottles)  can only come from dairy herds that are currently 100% TB free. The greater risk is from over crowded housing – a breading ground for TB. In  Southall, England it has become an epidemic – not because of milk but landlords allowing overcrowding of cheap and squalid accommodation. Many of their tenants come from  countries where TB is not treated properly so bring the disease in with them. So it is a profit issue.  UK strains of TB can be treated with antibiotics but these new imported strains are more antibiotic resistant, due to some foreign counties not having the health-care services to ensure that the full course of treatment is complied with. In the UK it is the unregulated  movement (sale) of cows between farms that enable TB infected cattle to infect other cattle. So coming back to your point. DNA analysis suggests strongly that TB was primarily just a human disease. However, as primitive man advanced (?) and turned to animal husbandry, they passed it onto their cattle. The cattle in-turn passed it on to Broke the badger. So now we know who the Patient Zero's are (i.e., humans) perhaps Brock should really be thinking about culling us.--Aspro (talk) 23:02, 7 April 2016 (UTC)


 * by setting your oven to 146°F, which would indeed be a very low cooking temperature. That exactly what a sous vide is for. Vespine (talk) 22:17, 6 April 2016 (UTC)

Does it make sense to talk about temperature of particles?
Can the concept of heat be applied to photons, electrons, and protons? — Preceding unsigned comment added by Scicurious (talk • contribs) 23:33, 6 April 2016‎
 * Do you mean individual particles, or large collections of them?
 * Thermodynamics is a fundamentally statistical discipline. It studies only the random component of the behavior of systems.  So it really doesn't usually make much sense to speak of the temperature of an individual particle.  But you can certainly speak of the temperature of a "gas" of electrons, or of the photons in an evacuated chamber acting as a black body. --Trovatore (talk) 00:04, 7 April 2016 (UTC)


 * Yes, except for photons, would be expressed as velocity (m*v^2 is temperature). As above, it's statistical but also used to calculate collision rates. Example would be an Argon plasma at a certain temperature will have different velocities for electrons and the Argon ion. The different masses means that for the same temperature, the particles have different velocities and different collision rates.  A Langmuir probe is a device used to measure that temperature in a plasma.  Photons in a vacuum don't change velocites so temperature refers to a black body model.  See Color temperature for black body radiators and "Correlated Color Temperature" in that same article for emitters that are not black body radiators.  --DHeyward (talk) 04:25, 7 April 2016 (UTC)
 * Well, that doesn't work for an individual particle. As I said, it's only the random part that counts.  If you have a blast of particles all moving very fast in the same direction, it doesn't make them hot.  And so you really can't make a lot of obvious sense out of the notion of the temperature of an individual particle.  Maybe if you don't know its energy, but you know it's sampled from a Boltzmann distribution or something, it would make some sort of sense to describe your lack of knowledge in terms of a temperature.
 * Moreover, temperature is not simply related to kinetic energy per particle. That only works for monatomic ideal gases.  For anything else, it's a lot more complicated.  --Trovatore (talk) 05:44, 7 April 2016 (UTC)
 * As I said, it's a distribution. Average velocity is a measure of temperature. Collision rates are averages.  The fact that it's an average, though, doesn't change the measurement of temperature.  Even thermal conductors have an average and distribution.  Evaporative cooling is based on average and deviations of individual molecules.  Plasma physics are very dependent on average energy.  Debye length is about density and temperature, not deviation.  Solutions are provided for Boltzman distributions and that is standard theory, but it's not required as it can be solved for any distribution.  A blast of particles is not the same as a contained set and in that case both relative velocity distributions and burst energy are relevant especially if they hit a stationary target.  I didn't disagree with you, I just provided examples where temperature is used as a metric.  Langmuir probe was one such application and it's underlying causes are rather independent of the measurement.  You can even apply it to some solid state distributions where junction temperature affects the length of transition.  Thermoelectric effect is a solid state version of Debye length and describes average particle energy against a built-in electric field.  It's an "average" but no one argues that a thermocouple doesn't measure temperature even though every carrier has a different energy.  P/N junctions also have Vbi and the effective mass of "holes" and electrons makes the depletion region length different in equally doped semiconductors.  The absolute length of a P/N space charge region is temperature dependent with kT/q as a standard descriptor as a constant that varies only with average temperature..  --DHeyward (talk) 08:03, 7 April 2016 (UTC)
 * Also, it's rather intuitive that the distribution is dependent on density and material. Anyone that's been in a 68F office vs. a 68F ocean knows that carrier-transport/collision-rate is much greater in the ocean even if the temperature is the same.  --DHeyward (talk) 08:18, 7 April 2016 (UTC)
 * Well, average velocity is not a measure of temperature if there's only one particle. Not in general, really, either, but that's a different discussion.  It's not clear to me whether the original question was talking about gasses of particles, which can clearly have temperatures, or individual particles, which really can't. --Trovatore (talk) 17:35, 7 April 2016 (UTC)
 * For a slightly different take on the temperature of a particle, see Neutron temperature. Jim.henderson (talk) 00:23, 8 April 2016 (UTC)