Wikipedia:Reference desk/Archives/Science/2023 April 14

= April 14 =

water that has been lingering in the pipes
I'm in bottom floor of 4 story apt building. Landlord notified me that the water would be shut off for part of today for plumbing repairs, but I forgot about this, and needed 2 cups of water to make oatmeal. I turned on the kitchen faucet during the the shutoff period and water came out at about 1/4 of its usual speed, I guess draining from pipes in the building, but I was able to get my 2 cups and the oatmeal tasted fine.

Any idea if there are health hazards from this, such as metals in the water? Not worried about microbes in this instance since the water got thoroughly boiled for the oatmeal, but in other situations I guess those could be a concern too. Thanks. 2602:243:2007:9990:FC12:23ED:462:65F4 (talk) 00:32, 14 April 2023 (UTC)


 * It's highly unlikely to be a problem. For millennia people having been drinking water from water tanks and many other places where the water is stationary for quite long periods. HiLo48 (talk) 02:07, 14 April 2023 (UTC)
 * I'm puzzled as to why you think this could possibly be hazardous? Water is "lingering" in the pipes most of the time. It only flows when a faucet is opened. It's just as safe as water that has been lingering in a bottle. Shantavira|feed me 08:30, 14 April 2023 (UTC)
 * One reason is if there is lead in the plumbing. My house receives water from the main in the street through a pipe ("service line") about 30 feet (10 m) long, and it was a lead pipe from 1924 when the house was built until 2008 when it was replaced with copper.  At some point the city advised people who had a lead service line that they should run the taps long enough to flush the standing water out of the pipe each morning before drinking any.  I only heard about this when the pipe was about to be replaced.  I had a blood test for lead then, but it was negative, so I don't imagine the risk in such a case is very serious.  But is it possible?  Looks like it. --174.89.12.187 (talk) 05:39, 15 April 2023 (UTC)
 * If you have hard water the take-up of lead is reduced, in part due to scaling on the inside of the pipes. Martin of Sheffield (talk) 11:00, 15 April 2023 (UTC)
 * One possible risk is if someone about you had a hose on a tap running into a bath or something like that. It may siphon dirty water back into the plumbing. But your boiling would most likely render it safe. Graeme Bartlett (talk) 22:55, 14 April 2023 (UTC)
 * Plumbing term for this is backflow. For this reason large water systems frequently are required to have backflow prevention devices where they connect to the "global" water system. --47.155.46.15 (talk) 02:28, 16 April 2023 (UTC)

Nuclear laptops
Why are there tritium powered exit signs, but not tritium powered laptops? Someone who&#39;s wrong on the internet (talk) 03:55, 14 April 2023 (UTC)
 * Who says there aren't? Obtain laptop and betavoltaic power sources. Connect these to the laptop power charge socket. This might require a little custom wiring. Voila, tritium-powered laptop. The neat thing about electric power is things that use it don't care what the source of the energy is, and thus you can use anything that provides the needed electrical power characteristics. Sun-powered car, sure why not?
 * A more comprehensive question in line with what you're probably thinking is, "Why don't people sell a lot of laptops with integrated betavoltaic sources", which is a question at the intersection of engineering and economics. Such laptops would be bulky in order to provide the necessary power—dimly lighting a sign takes a lot less power than a typical consumer computer. The overwhelming characteristics purchasers want in portable electronics are light weight and easy portability. The demand isn't there. And as covered, you can just connect the laptop to pretty much whatever you want, which then lets you connect/disconnect as desired. Power banks and portable generators and fuel cells are all available. (Modern ICE automobiles double as electrical generators with their automobile auxiliary power outlets. Electric vehicles often have them as well, though in an all-electric you're of course drawing down the vehicle batteries instead.) 47.155.46.15 (talk) 04:27, 14 April 2023 (UTC)


 * "Who says there aren't?" I'm willing to say it. There isn't such a device available for commercial sale, and nobody has ever chained together enough betavoltaic sources to power a consumer laptop. An efficient low-power laptop might draw as little as 20 watts. The total energy output from tritium decay is something like 0.3 watts per gram, so that's a minimum of 60+ grams of tritium (about 60,000 curies) to get 20 watts of heat. At $30,000 per gram, that's two million dollars worth of the stuff. And that's making the - totally unrealistic - assumption of perfect conversion to electrical energy. (In real betavoltaic devices, I think the figure is less than 1%.) TenOfAllTrades(talk) 13:40, 15 April 2023 (UTC)
 * Right, that's a part of what makes it economically unfavorable. Though, you could charge a battery with beta sources. Even if the lithium-ion batteries in modern laptops are finicky about their charging input, you can always wire up a different battery type that's easy to trickle charge. --47.155.46.15 (talk) 02:25, 16 April 2023 (UTC)

Cenozoic dinosaurs
Are there surviving non-avian dinosaurs from the Paleocene? I have heard of trodons, hadrosaurs, surviving microraptors or even small oviraptors that lived long after K-T. BristiBoop78786778 (talk) 07:25, 14 April 2023 (UTC)


 * Wikipedia has an article about dinosaurs. The first paragraph says that all non-avian dinosaurs are extinct. Shantavira|feed me 08:24, 14 April 2023 (UTC)
 * That's what they want you to think. —Tamfang (talk) 18:51, 16 April 2023 (UTC)


 * More specifically you can read Dinosaur. Ruslik_ Zero 12:22, 14 April 2023 (UTC)

Mentalism
https://timesofindia.indiatimes.com/india/just-mind-games-indian-mentalists-are-busting-the-chamatkar-myth/articleshow/98052200.cms

I have seen some videos on news channels. They touch somebody's hands, they ask them to mention some number and they give personal details which they are not supposed to know. Sometimes they even read thoughts.

Are these staged? Mean the girl among the audience knew the mentalist and she was trained to fool the audience. They are telling this as some art, but they are demonstrated as some supernatural power like telekinesis.

I also want to know about these tarot card readers that appear so many time in Hollywood movies. Do Americans visit tarot card readers? Arjun Singh 2004 (talk) 09:57, 14 April 2023 (UTC)


 * You linked the word Mentalism in the section title here. Did you read that article? HiLo48 (talk) 10:40, 14 April 2023 (UTC)
 * Probably not "staged" in the sense of a shill (stooge). It could also be a case of hot reading which might qualify as "staged" depending on your definition. However, without having looked at the article or video, your description does not seem impossible to achieve by means of cold reading.
 * In the case of videos, editing also comes into place: in the words of Penn and Teller, if I show you a video of someone picking a card and the magician immediately telling which card it is, that’s impressive, but if I tell you the magician stood for two hours in the street and the camera operator made about fifty takes, less so. Tigraan Click here for my talk page ("private" contact) 12:53, 14 April 2023 (UTC)
 * Probably the words of Penn … —Tamfang (talk) 18:53, 16 April 2023 (UTC)

Has English subtitle- https://www.youtube.com/watch?v=TEZoVK33TZU — Preceding unsigned comment added by Arjun Singh 2004 (talk • contribs) 13:45, 14 April 2023 (UTC)
 * Yes, I see nothing there that can't easily be explained by the explanations already provided above 1) The person being so interviewed was a "shill" or a "plant" (they were a rehearsed part of the act) 2) The stage performer had prior knowledge of the audience member (she had filled out a survey of some sort, not knowing what it was for, for example) or most likely 3) The stage performer is well-trained in the techniques of Cold reading. Most of the time, this is how they do their tricks.  It could also be 4) Cherry picking a specific time that he got it right from among many performances, and only putting that one on the internet for you to watch.  Less likely than a good cold reading.  -- Jayron 32 15:46, 14 April 2023 (UTC)


 * In the 20th-Century Western Mentalism and Spiritualism 'industry', many believing customers would attend as many shows and/or seances as possible. Long before the computer age there was an organisation to which the performers would send data about their clients, garnered during or before seances and at theatre performances (by mingling in the foyer, etc.). This was compiled on file cards, and if one or more regular participators were identified as being in the audience of a show, the Mentalist's assistants could phone the organisation and be given all the facts known about them. Sorry for no reference, I've been interested in such subjects for half a century and have long known this.
 * Obviously, modern comms and computing would make this even easier than before. {The poster formerly known as 87.81.230.195} 90.213.18.208 (talk) 19:13, 14 April 2023 (UTC)


 * See also cold reading and hot reading for details of the techniques. For an actual example, see Doris_Stokes, a famous British medium who died in 1987 shortly before her audience planting techniques were revealed. Alansplodge (talk) 13:04, 18 April 2023 (UTC)
 * Died at age 67. I wonder if she saw that coming. ←Baseball Bugs What's up, Doc? carrots→ 14:58, 18 April 2023 (UTC)
 * Her business was permanently closed due to unforeseen circumstances. --  Jack of Oz   [pleasantries]  23:04, 18 April 2023 (UTC)