Wikipedia:Reference desk/Archives/Science/2015 September 20

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September 20

Why don't people use jetpacks? Because the tech exists, as I understand it.

Are the main problems basically to do with accidentally setting your legs and ass on fire and/or running out of fuel in mid-air and dropping like a stone? Anyone able to explain in layman's terms? Thanks. -84.51.162.182 (talk) 01:39, 20 September 2015 (UTC)

See risk analysis. Most air-bound travel systems (aside from commercial airlines, which are very safe because of well-established safety protocols and improving control systems) suffer from the problem of providing very little benefit in terms of improved travel times/costs coupled with catastrophic failure modes. In other words, the risk associated with death from failed jet pack isn't worth the marginal improvement in mobility over ground-based methods. --Jayron32 01:43, 20 September 2015 (UTC)

See Jet pack. They are expensive, have a short flying time, and are probably dangerous. Bubba73 ^{You talkin' to me?} 01:46, 20 September 2015 (UTC)

Considering how much danger hobbyists' drones are causing, imagine how it would be with people themselves flying around. ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:54, 20 September 2015 (UTC)

I agree that they aren't practical on Earth, but they seem better suited to space. See astronaut propulsion unit. StuRat (talk) 02:59, 20 September 2015 (UTC)

Most problems have already been mentioned, and most apply to the "Why are there no flying cars" queston, too.

• Fuel cost
  • In currency; the average citizen can't afford flying.
  • In weight; you can only lift so much (MythBusters came really close to flying with a "helicopter pack" but they didn't actually take off – imagine how much worse a lot of fuel would make the situation) Consequence: you can't fly for long (a minute or two in most cases).
• Traffic. While one would think another dimension would provide infinitely more space, that's not true in practice. The point of flying is to land somewhere, so there's a lot of traffic near ground level (although it's less of a problem away from the endpoints). Look at road traffic, and then think about how chaotic airspace would be if all those guys were flying around! Air traffic control is a huge task even if the flying personnel are few and well trained.
• Situational awareness. You have to watch an entire hemisphere around you to avoid collisions, and that's if everybody agrees to fly forward, no aerobatics.
• Speed and accidents. Jetpacks are quite slow and about as safe as a motorcyclist, if not less. Even collisions at low speeds (about 10m/s, 36kph, 22mph) are severe if not fatal. Next point down the list only adds to it.
• Fail-deadly. What happens if your jetpack breaks down, or runs out of fuel, in flight? You don't grind to a halt, you're going down, fast (and then you grind to a halt – messily). What happens if two collide? The same, times two. BTW, in dense traffic patterns, there's quite a risk of running into other flyers on your way down. Atmospheric Kessler syndrome.

To make a long story short, the helicopter is about as close as we can get to a flying car (decent safety and fuel capacity/economy, high unit prices lead to limited numbers which lead to manageable air traffic), and jetpacks or air-cycles are pretty much sci-fi dreams. - ¡Ouch! (^{hurt me} / _{more pain}) 07:11, 21 September 2015 (UTC)

For an entertaining (and to some degree harrowing) fictional treatment examining the implications of freely available jet pack-like technology (actually anti-gravity harnesses), see Bob Shaw's novel Vertigo aka Terminal Velocity. {The poster formerly known as 87.81.230.195} 185.74.232.130 (talk) 13:34, 21 September 2015 (UTC)

The hard part is inventing the calf shields. ^Avic_ennasis @ 02:17, 10 Tishrei 5776 / 02:17, 23 September 2015 (UTC)

I should point out that the article says there actually has been a 9-minute jet pack built, allowing someone to actually cross the English Channel with one, which is definitely a lot better than the 30-second curiosities I've read about. Since they say that engineering small, light jet engines is an issue, I suppose that better materials and fabrication technology might allow some further progress on this front. Still... until you can actually go somewhere with one, all the other good arguments not to use them aren't even relevant. Wnt (talk) 23:40, 23 September 2015 (UTC)

I have to disagree with you there. If they were perfectly safe, they would be popular just for entertainment purposes. At one time, hot air balloons, tethered to the ground, that just went up a few hundred feet and then landed in the same spot, were quite popular at county fairs, etc. StuRat (talk) 23:44, 23 September 2015 (UTC)

You may have a point there - I was thinking of a slightly different philosophical concept for "use". As entertainment, clearly safety can be improved if it has something similar to self driving car software. Which brings us to propulsion. Electric cars (especially the Tesla brand) have been becoming known for being able to put on bursts of power comparable to gas-powered vehicles. Can you make an all-electric jetpack, powered only by batteries, that releases relatively mild heat? I have this image in my head of the Horsey, a small jetpack given as a present to children, that has a big red button on the front; if it's safe, it lifts the child about six feet in the air, to see over the heads of adults in a crowd, before automatically landing again. Such a thing would need many & various thrusters I suppose, making it less efficient, but still it ought to be good for a few hops before the power runs out. Wnt (talk) 12:40, 24 September 2015 (UTC)

why does the clock of Ahmed Mohamed has so many cables and looks like a bomb?

I can find only pictures in the internet where is his clock shown in a case and it really looks like some kind of a bomb... But tell me, what can his clock do, what a Rolex doesn´t? I can´t believe that all this cables are only to show the timer at the display. This clock must be able to do something, what a rolex doesn´t. What is it? Has somebody of you seen his clock working?--Hijodetenerife (talk) 21:47, 19 September 2015 (UTC)

It looks like what you think a bomb should look like, because you've seen pictures of "bombs" with leads sticking out of a timer, connecting it to explosives. This kid has created this clock from a few bits he's thrown together which he found at home. If he'd have found the bits to make a Rolex at home, then no doubt he'd have created a Rolex. Why shouldn't anyone make something out of what you find at home? You can make a oommunications system out of two tin cans and some wet string, you know! --TammyMoet (talk) 09:05, 20 September 2015 (UTC)

I agree to this. I have also seen in movies always bombs in a suitcase.--Ungerechtfertigter Sperrer (talk) 08:21, 21 September 2015 (UTC)

How do you mean it has "so many cables"? Here's an image of the clock with the parts labeled. There's a cord that plugs into the wall, a pair of wires from the transformer to the mainboard and a pair of wires to the battery connector. Oh, and a flat cable to the display. It looks like the minimum needed for this type of clock. You do understand that cables need to be in pairs to transmit power?

As for looks like a bomb: it doesn't. If anything it looks like the kind of prop used in movies and TV shows to represent a bomb. [1]Sjö (talk) 09:37, 20 September 2015 (UTC)

a pair of wires from the transformer to the mainboard - why the hell should a clock really need a mainboard like a Macbook?--Ungerechtfertigter Sperrer (talk) 08:21, 21 September 2015 (UTC)

Tell me, how does it look like a bomb? Which bomb has gigantic LED displays? Which bomb contains no explosives? Which bomb has no sealed containers? Which bomb is contained in a pencil case? Which bomb plugs into AC power? Is there a terrorist who has to plug his bomb into the nearest power outlet to make it work? If you think this looks like a bomb, you are simply wrong--it looks nothing like one. This is what a bomb looks like: https://upload.wikimedia.org/wikipedia/commons/a/a5/IED_Baghdad_from_munitions.jpg http://www.columbine-online.com/attack/columbine-attack-bombs.htm http://images1.browardpalmbeach.com/imager/margate-man-tried-to-kill-lovers-husband/u/original/6467222/pipe_bomb_oct.jpg http://pl.b5z.net/i/u/6070324/i/ec/OTA-977_Pipe_Bombs_and_Cut-Aways_i2_ezr.jpg As for "I can't believe that all this cables are only to show the timer at the display," take apart an alarm clock and you'll see just as many cables. If you can come up with a clock that doesn't require as many cables, please let us know. --Bowlhover (talk) 09:46, 20 September 2015 (UTC)

You have posted pictures of regular damn bombs from a tank or airplane, Ahmed Mohamed has a suitcase and we all have seen bombs inside of a suitcase: (for example Rush Hour, Speed and all this movies, I can recommend) - a timer and C4. Simple, right? And like this way this clock looks like a bomb, only C4 is missing to be honest. I don´t understand your pictures, is that a joke?--Ungerechtfertigter Sperrer (talk) 08:21, 21 September 2015 (UTC)

Oh, I see! I posted real pictures of real bombs, whereas your idea of what a bomb looks like is based on fake bombs in fictional movies. My bad for giving an answer that's based on reality and not make-believe.

"And like this way this clock looks like a bomb, only C4 is missing to be honest."

Oh, I see! This clock looks like a bomb, except it doesn't have the one and only essential component of any bomb. Similarly, the Pacific Ocean looks like the Himalayas--only water is missing. Also, a grassland looks like a jungle--only trees are missing. --Bowlhover (talk) 09:13, 21 September 2015 (UTC)

I also would say, that just C4 is missing, exactly this kind of suitcase bomb I was thinking about, Like this and not this pictures what you have given...--Hijodetenerife (talk) 18:46, 22 September 2015 (UTC)

Yes, that image is not of a real bomb (here is another page from the same website). Anyway, a fake bomb like the one in your image has something to represent the explosive. That's one of the biggest differences between Mohamed's device and a "movie bomb". Of course, the difference between his device and a real bomb is even bigger as Bowlhover showed. Sjö (talk) 19:57, 22 September 2015 (UTC)

Disclaimer: The Refdesk doesn't give advice -- no, we can't suggest you take apart your alarm clock, because you might get arrested as a terrorist! Wnt (talk) 11:20, 20 September 2015 (UTC)

It isn't directly relevant but may be worth mentioning that no one involved in this situation seems to have ever believed that the clock might actually be a bomb. No one called a bomb squad or evacuated the school. -- BenRG (talk) 21:56, 20 September 2015 (UTC)

Please tell us more! I know only he got arrested in the school but I have really not heard who took the clock and who called the Police. --Ungerechtfertigter Sperrer (talk) 08:21, 21 September 2015 (UTC)

The charge was a "hoax bomb." They knew it wasn't a bomb but the question is about intent. Most threats including bomb threats are not real but that doesn't mean the provocateur has not committed a crime. Even if he play-dough with wires in it, that wouldn't make it a bomb either but the same reaction (or harsher). "It's a clock with play-dough." This is basically a zero-tolerance policy and applies to all kinds of innocent items. A second-grader was suspended for chewing his pop-tart into a shape of a gun and pointing it at kids. Nobody is afraid of the pop-tart but he still got suspended. And everyone is familiar with "joking" policy at a TSA checkpoint - joke and you don't fly. --DHeyward (talk) 04:30, 21 September 2015 (UTC)

There is one rather careful analysis out there: here (v.slow right now) - which conclusively demonstrates that the kid did not "invent a clock" or "design a clock" or even "build a clock". What it seems that he did was to take an existing electric alarm clock (a circa 1986 Tandy model PICTURE HERE), remove all of the 'guts' from the case - and dumped them into his lunchbox. The evidence for this is in the silk-screened serial number on the circuit board which matches the Tandy clock - and the obviously identical display. The original clock had a small mains transformer and a 9v battery backup - both clearly visible in the photo of the clock in the lunchbox.

Clearly, this is something that didn't take the kind of intelligence that's gotten MIT "interested in him" or the Whitehouse to invite him to show his "invention" to the president - he's claimed to have designed and built the clock - and evidently managed to fool a lot of people.

This news does rather change the dialog. We no longer have "genius kid is misunderstood". What this now boils down to is whether he intended to try to make his teacher/classmates believe that he'd invented something (when he evidently had not) - or did he really intend it to look like a bomb? We can't know what was in his head...and his fate depends entirely on which of those two things it was. All we really know is that he didn't invest a lot of genius brainpower to do it...any kid with a screwdriver could have done this. If he gets a free pass into MIT for doing this - then all of the people who don't get into MIT should be seriously pissed!

SteveBaker (talk) 13:47, 21 September 2015 (UTC)

Agree with Steve. See also also another analysis here [2]]. It seems the parents are associated with CAIR, who is an organisation with political goals and this event certainly has had a effect that serves CAIR's general purpose. It also seems that the school and police followed the rulebook precisely, (maybe too precisely to some people's taste). --Lgriot (talk) 14:13, 21 September 2015 (UTC)

Yes, and my parents are "associated" with the country of China (even though I am not), which generally believes in science and technology. I've also brought electronic projects to school and work before. Therefore, me bringing completely innocuous electronics that look nothing like a bomb must be an influence operation designed to further Chinese goals. The operation would only work in the unlikely case that the one teacher who accidentally discovers my device happens to have no IQ points. --Bowlhover (talk) 17:28, 21 September 2015 (UTC)

Fair enough, it is very possible that this boy was not being manipulated, at first. But now it certainly does look like CAIR have taken control of the family. I don't know whether CAIR was involved before the event, and his motives for removing an alarm clock from its case and pretend he had build it remain unknown. Anyway, this discussion is not a science question any longer. Should we hat? --Lgriot (talk) 20:49, 21 September 2015 (UTC)

Breitbart isn't a reliable source which makes the second analysis somewhat questionable. Sjö (talk) 04:42, 22 September 2015 (UTC)

I think given how politicised this has become, there's a fair chance we will never know what really happened here. But we should also be careful with not overestimating what we do know.

Saying the child "pretend he had build it remain unknown", is not sufficiently supported by the evidence. "pretend" implies there was intentional disinformation, yet as even Dawkins has acknowledged, we are referring to a 14 year old child and even though it may be a little odd for a 14 year old with a good level of English to call the clock an invention or saying he built it when it appears he mostly disassembled an existing clock, we don't know what was meant my these statements. Also, AFAIK, we don't know, and may never know, precisely what was said, for example, to the engineering teacher about the clock, and it seems a little strong IMO to say he "pretend"ed he built it based on statements given after the shitstorm, even if it happens he did knowingly mislead after being overwhelmed by the attention.

Also, we should remember that whatever the politics of the parents, we can't assume their actions are mostly a result of any political leanings, as opposed to an obvious desire to protect their kids (whether or not their actions are good or achieve that).

P.S. Given how litigious things can be in the US, am I the only one surprised neither teacher apparently made a fuss over there being potentially exposed live wires on this device which the kid was apparently plugging in to show people? Well it's possible the engineering teacher did say have concerns about this, I'm not sure if we know precisely why they said the clock should be kept in the backpack.

Although the most surprising thing to me was to learn that it's apparently somewhat common in the US, unlike what's shown in TV shows which admitedly are normally set in New York or perhaps California, that the police can detain a child and question them about their alleged offending without an adult or someone to represent the interests of the child present. [3] [4]. Seems a little odd to make such a big deal about the Mirandi Warning, but not worry about whether the person is likely to understand it all. As far as I know, in NZ it's generally expected an adult will be present to help the child [5].

Admitedly there was dispute over whether a parent was specifically asked for which I believe normally should be granted, and other aspects over how this was handled [6] although I appreciate this is complicated by the fact police can't release all details due to confidentiality requirements. I'm presuming of course there was the intention that the questioning would potentially lead to a charge, and also as BenRG and others have said, no one believe there was an imminent threat.

Nil Einne (talk) 23:42, 23 September 2015 (UTC)

@Nil Einne: I am not sure which is worse: that he was trying to mislead when he said "invention" or that, at 14 year old, he doesn't know the meaning of the word "invention". Is it a worst insult to be called dishonest or very stupid?--Lgriot (talk) 15:18, 24 September 2015 (UTC)

@Nil Einne: I have to say the same thing crossed my mind - as a matter purely of school policy, I'd have thought there'd be some kind of "live wires" clause. I mean, if a kid came into school carrying a yanked-out electrical cord with a plug at one end and two bare wires at the other, a teacher might rightly be concerned what might happen. And admittedly, the criminalization of even the most elementary kid stuff in the U.S. creates a position where such a thing - terribly - can become a police matter. However, that is always wrong, whether it is a fistfight or a threat or anything else, and where discipline is concerned, part of a well-run school is that those who show competence and have a reason should be allowed to bring things that have a mild level of danger associated with them. Indeed, American schools used to be known for their rifle teams, which the students would take into the bus properly stowed unloaded in cases; though perhaps that is a bad example since the kids could end up harming their hearing. Wnt (talk) 12:48, 24 September 2015 (UTC)

It is worth noting that the police / local government declared they were not going to prosecute the kid the morning after this hit the news. Their statement essentially acknowledged that Ahmed had never intended any harm (intend to create fear is one of the required elements for a "hoax bomb" charge). Dragons flight (talk) 21:09, 21 September 2015 (UTC)

Also, the article about this case is at Ahmed Mohamed (student), though it is currently nominated for deletion. Dragons flight (talk) 21:13, 21 September 2015 (UTC)

Magnetic core for an electromagnet?

An electromagnet consists of a coil through which a current passes. This can be made more effective by putting a metal core in the coil. But what if you use a magnet for a core? Would that make any sense? And could you then (partially) de-activate the magnet by passing a 'counter-current' through the coil? Probably a useless thought, but I was just wondering. DirkvdM (talk) 10:26, 20 September 2015 (UTC)

This is the basic principle of the self-keeping relay - no article, but see Relay, and search for the term more generally. Tevildo (talk) 10:56, 20 September 2015 (UTC)

Ah, interesting. I was indeed thinking about a switch. Knowing very little about electricity, I came up with this, but thought it was too silly. Still, it intrigued me, so I asked. Turns out it's not silly at all. Thanks. DirkvdM (talk) 15:59, 20 September 2015 (UTC)

Wouldn't you know it; someone asked a question about something I spent twenty years studying and repairing. Alas, I can't find online an explanation as clear as the training materials that taught me in the 1970s, though this BSTJ article covers it for engineers who already have the engineering background of both relays and the somewhat related magnetic core memory technology. But yes, millions of these "ferreed" and "remreed" magnetic crosspoints were built, and they worked, simplifying terribly, by applying a brief current pulse in the coils surrounding the crosspoint. Each of the millions of crosspoints was a tiny and very simple magnetic latching relay. Hmm; ought we make redirects? Jim.henderson (talk) 13:18, 24 September 2015 (UTC)

Were these widely used? My father worked in telephony, I heard about the magnetic core memory and reed relays, but not the ferreed. Maybe they skipped that stage, I remember in those days some exchanges in Brussels were still electromagnetic with motors and turning switches, while others already had "modern" ITT 10c Stored Program Control. Ssscienccce (talk) 23:52, 24 September 2015 (UTC)

How do electronic water conditioners work ?

Note that the link in the title redirects to "magnetic water treatment", which I don't think is the same thing. Here's a link to what I mean: [7], which appears to be a production model, not the theoretical magnetic model. It boasts it can take the excess minerals out of hard water without adding salt. So, does it use a positively charged plate and a negative plate ? If so, wouldn't the plates need to be frequently replaced, and wouldn't hydrogen and oxygen also be produced by the electrolysis of water ? StuRat (talk) 14:23, 20 September 2015 (UTC)

If you ignore the marketing junk, at about 1:50 the video in your link suggests the device uses sonic waves to stop calcium adhering to pipes and appliances.

I have doubts that the device works anywhere near as good as the video claims (if at all), particularly all the claims about the water feeling "silkier" and reducing eczema, skin feeling smoother etc, but I don't see where it "boasts it can take the excess minerals out of hard water without adding salt".

On the contrary, the video seems to imply the calcium and magnesium ions aren't removed, it specifically mentions them being "healthy" and the device being an alternative to water softening (point blank).

The text also compares it to water softeners and "non-intrusive to the water" (whatever that's supposed to mean, but I guess anything reducing the calcium and magnesium ion concentration could be consider intrusive).

The closest seems to be "solves hard water problems without the need for chemicals, salt or maintenance", but that says "problems", which seems to imply it's supposed to solve the problems caused by hard water, rather than hard water being a problem that needs to be solved (i.e. it's making the hard water soft).

Nil Einne (talk) 15:03, 20 September 2015 (UTC)

Wow, sounds like a total scam. I'm surprised it would be sold at a reputable big box store. I just took "silkier" to be marketing talk for "fewer minerals", as soft water could be described that way ("greasier" or "slimier" might be less charitable ways to describe it). StuRat (talk) 15:10, 20 September 2015 (UTC)

Walmart sells homeopathic 'medicines', Target sells homeopathic 'medicines' for your pets (good luck with the placebo effect there!). Our local HEB supermarket sells those foot pads that "draw toxins out of your body through the soles of your feet". Home depot offers free water test kits where the water isn't tested at all, but instead they use your zip code to give you a generic result and collect your name and address so they can spam you with water softener adverts from now until eternity. Where exactly are you finding these 'reputable' big box stores?!? SteveBaker (talk) 13:24, 21 September 2015 (UTC)

I found [8] which talks about several different types of these products, confirming my suspicion they're all basically scams. While it doesn't talk about the Scale Blaster in particular, it does talk about Scalewatcher which appears to advertise a similar principle of using sonic waves.

There are also ones claiming to use an EM wave. And of course all the magnetic ones our article talks about, which have been scamming people since 1998 [9] and probably long before. Most sources do talk about these magnetic ones which seems to be most common and definite bullshit (the alleged wonders of magnetic crap are so common, I was fairly sure of this before even reading even our article).

I had a strong feeling the Scaleblaster was the same, but it's useful to establish how the device is claiming to work (if they do claim a method), otherwise supporters and salespeople will just claim "sure the magnetic ones are bullshit, but our ones...".

Notably, the science part of their website just repeats the same crap as in their video with no evidence of studies or anything supporting even the basic claim of sonic waves reducing adhesion [10]. (There's also IMO a strong implication the calcium is semi permanently alternated to be non-adhesive ala homepathy etc, rather than just a temporary effect in water that is significantly affected by the sonic waves.)

This is perhaps one area where ScaleBlaster are "smarter" than Scalewatcher. Unlike Scalewatcher who claim to work by Magnetohydrodynamics, Scale Blaster just mention sonic waves and reducing adhesion, which sounds bullshit but there's no principle people can easily check to confirm it is. They also avoided such obvious junk as "The signal consists of a frequency modulated (FM) wave form within the audio frequency (AF) bandwidth. This inaudible sonic frequency signal...".

Nil Einne (talk) 15:34, 20 September 2015 (UTC)

I would certainly bet money against this being legit; nonetheless, I can think of a hypothesis by which such an approach might make sense. Suppose your source of hard water contains some small crystal nuclei - in other words, it is heavy in calcium-magnesium, but there's some little flecks of Ca/MgCO3 in it. Then if you could use sound to break up all the flecks, it is possible (definitely not certain) that this would hinder the growth and adhesion of calcium deposits, because the crystals would grow more slowly. Caveat being that a metal surface might nucleate crystals all on its own; I have no idea whether stray mini nuclei in solution have anything to do with it at all. But even if I see this theory written up in a water conditioning project, I'm just going to assume they're chiselers plagiarizing me, unless I see some pretty impressive data in a real scientific journal to back up their claims. Wnt (talk) 15:49, 20 September 2015 (UTC)

@ User:StuRat and the others posting here. The advertisement did not boast it can take the excess minerals out of hard water. It states and I quote: “prevents lime scale deposits in household pipes” ( not a 100% in the real world I will grant you but better than nothing). These devices have been used in industry for years and industry does not go in for the pseudo-science that some here are suggesting Water purification using magnetic assistance: A review. The little red & black terminals on that box go to a coil wound around the pipe. The magnetic field interferes with nucleation that normally allows crystallization of calcium carbonate (scale). So that the foreman can see that the device is still working, the coils are wound around a non-metallic plastic transparent pipe. The internal surface of the pipe going into the coils gets coated with crud and the out flow surface stays cleaner. Does any one think that the night-watchman keeps cleaning out the out-flow when everybody has gone home for the evening – I think not! In yesteryears these conditioners ran on thermionic tubes which made them very expensive and out of the reach of the ordinary John Doe. Now they are cheap and affordable. Whether the aforesaid example works as advertised I don't know but it is not pseudo-science.--Aspro (talk) 17:14, 20 September 2015 (UTC)

I think we already established that the device doesn't claim to remove excess minerals for hard water. However we also established the unlike some devices, this device does not claim to use "magnetic assistance", it claims to use sonic waves.

Note that it also doesn't claim to simple reduce scaling by a small percentage, it claims to eliminate it as your own quote shows. Or more clearly "Lime scale will no longer form in the pipes or on equipment that comes in contact with hard water. This results in the lowering of the saturation level of hard water, so that new lime scale is prevented and any existing scale is removed."

Scaleblaster evidently do make some magnetic devices for industrial use. But the possible effectiveness of some industrial magnetic devices for a specific purpose i.e. reducing scaling, tells us nothing about the effectiveness of a device which doesn't even use magnetic fields, and for other purposes.

The claim of the magnetic devices reducing scale may very well not be pseudoscience, but the other claims do appear to be, that's why many sources rightfully call them so. Beyond the two I included above ([11] [12]), there's also [13] [14] [15] [16] [17] [18] [19] and many more. (This isn't that different from acknowledging that increased vitamin C consumption whether via supplements or fresh fruits will have some benefits from people who are deficient, but claims like it will cure cancer are largely pseudoscience.)

In fact, if you take a careful read of those sources, not all of them are really talking about the other purported effects. There's quite strong scepticism about whether the basic claim namely in reducing scaling really happens much even with the magnetic devices. The sources mention problems with some of the published science such as poor controls (e.g. failing to establish that it's actually the magnetic field, instead of something about the redesign required to install the device or construction of the device which the water passes through that reduces scaling), as well as the fact that the number of published science on negative results tends to outweight the positive.

One other big problem with the field already discussed is the tendency of manufacturers to come up with highly exaggerated claims of effectiveness, and bullshit other myriad benefits particularly for residential devices. As well as manufacturer's absurd claims of how their devices work rather than simply saying they don't know, but here's the high quality published evidence they do. Funnily your own source says "Owing to several parameters responsible for de-scaling, the superiority of one mode of operation over another is therefore difficult to predict". But of course if someone claims their device works, they should be able to come up with some evidence of how well their device works and predictions don't matter any more. There should be some industrial standard or several if some devices are more effective in differing circumstances, even if just defacto ones for how to compare the effectiveness of these devices, but apparently there isn't.

So even though certain magnetic treatments may reduce scaling in certain circumstances, there's a good chance even many of the industrial ones don't actually work much. Let alone the residential devices not all of which even claim to use magnetic fields (like the one discussed here which just to repeat for the final time, claims to use sonic waves).

Nil Einne (talk) 07:02, 21 September 2015 (UTC)

? where did StuRat's example claim to use sonic waves ? ScaleBlaster-Deluxe. That’s the sort of misdirection that pesudo-skeptics love to use. Oh, and bye the way, thanks for all your links to other psudo-skeptic sites. Comming now to some of your Quote: One other big problem with the field already discussed is the tendency of manufacturers to come up with highly exaggerated claims of effectiveness. Now My Question: Have you ever achieved the milage per gallon form your automobile that the manufactures claim? Which pot or kettle are you calling black? Quote: This isn't that different from acknowledging that increased vitamin C consumption whether via supplements or fresh fruits will have some benefits from people who are deficient, but claims like it will cure cancer are largely pseudoscience. Refer you to Reductio ad Hitlerum. Your playing the "playing the Nazi card" by referring to something unconnected. Quote:The sources mention problems with some of the published science such as poor controls. But of course if someone claims their device works, they should be able to come up with some evidence of how well their device works On this point Nil Einne may have come up with something that save us tax payers a lot of money. Military aircraft are fitted out with very, very expensive ejector and parachute systems. However, these have never been subjected to any good randomized controlled trials. Therefore, the military contractors (based on the thinking in the posts above) are probable ripping us (the tax payer off) and we should have them all removed until the self appointed psudo-skeptics are satisfied that they work as advertised. Would any of pseudo-sceptics like to volunteer to be the dummies in the aircraft without exit systems or would they about-face and claim they are really an unrepresentative cohort – all of a sudden. --Aspro (talk) 13:01, 21 September 2015 (UTC)

Attention all pseudo- skeptics! Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomised controlled trials. Get going and let the John Doe's know his tax payers dollars are being wasted on unproven fringe science. Oh, Float down to earth gently - who can believe that? --Aspro (talk) 13:22, 21 September 2015 (UTC)

We do use ultrasound for cleaning things like jewelry - so it doesn't seem immediately impossible that ultrasound might clean the calcium deposits from your pipes. Which is something that a hypothetical scammer might rely on you to remember.

However, the issue is with attenuation and reflections. The amount of power they use would have to be low enough to avoid cavitation in the water - because that would erode your pipes, which would be a seriously bad problem. It appears that this would limit them to using no more than 10 watts per square centimeter of pipe cross-section. Attenuation gets to be more of a problem with higher frequencies - so it seems likely that they'd want to pick a frequency that's just high enough to avoid bothering people and pets. I couldn't find a number for attenuation in water - but several papers concerning the attenuation of ultrasound in the human body should give us a 'ballpark' figure - which is 0.5 dB/cm/MHz. So at 1MHz, you get 0.5dB per centimeter. I'd bet that most houses have pipe runs over 10 meters, so there must be around 500 dB of attenuation in some parts of the house...if just 10 watts go into the pipe to avoid cavitation, then at the far end of the pipe, there's negligible energy left to do any cleaning.

Even if there were enough energy somehow - then we'd have to think about how our pipes are made. Most pipes these days are soldered copper. The very worst thing for destroying solder joints is vibration. How would those solder joints stand up to ultrasound that's powerful enough to remove calcium? How will the rubber/plastic washers in your faucets and toilets survive?

We might maybe hypothesize that the pipes act like some kind of wave-guide to prevent some of the sound attenuation - but what about when the pipe opens out into your hot water tank?

Also, sound waves suffer interference - with all of the 'dead ends' in the pipes because of faucets and toilet fittings that are currently turned off - the sound waves would reflect back down the pipes...what effect would that have? For sure you'd get 'dead' zones where the sound waves were cancelling out and your pipes would still get blocked.

I have to call "bullshit" on this one.

SteveBaker (talk) 13:24, 21 September 2015 (UTC)

Cavitation is only a problem on a surface where the energy during the implosion is high enough to pit the material. The device mentioned does not use sonic but a magnetic field so this reply is moot.--Aspro (talk) 13:55, 21 September 2015 (UTC)

Above here, we're talking acoustics - not magnetics. With non-magnetic water flowing through non-magnetic pipes and leaving non-magnetic deposits...it's kinda hard to see how magnetism would do a darned thing...unless you have a strong enough field for paramagnetic effects to happen (and you don't have that much field strength, for sure). With an acoustic actuator, the copper pipes are the surface that the cavitation would occur at if the power was sufficiently high - and they would erode as a result. SteveBaker (talk) 20:15, 21 September 2015 (UTC)

The OP's question is about "magnetic water treatment”. I don't know about what the above and you're talking about either, so keep it to yourself ;¬) --Aspro (talk) 20:48, 21 September 2015 (UTC)