Wikipedia:Reference desk/Archives/Science/2009 January 12

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January 12

A pile-up limit?

Regarding this from a local newspaper reader's response to a major traffic pile-up report:

I've never been able to understand 50 car pile ups. I'm not trying to be funny but you would think that after 40 or 45 cars are in a huge pile, it would give that 49th and 50th car a chance to slow down and avoid the mess. - Christian, Plaistow

...and it made me wonder if there is a "limit" beyond which the "huge pile" would prevent any further collisions. Honestly, I could never have come up with this one on my own :( -hydnjo talk 00:36, 12 January 2009 (UTC)

Do 50 car pile ups actually happen? I've never seen more than 5 or 6 cars involved in one accident. --Tango (talk) 00:38, 12 January 2009 (UTC)

What was I thinking? We, of course, have an article: Multiple-vehicle collision. Apparently they happen when there is poor visibility, so I guess the 49th and 50th cars don't know about the accident until they're part of it (you would think they would at least hear something, though...). --Tango (talk) 00:47, 12 January 2009 (UTC)

.Real time. Happened today (11 Jan '09 in Derry NH US) which is why the newspaper questioner posed the question. -hydnjo talk 01:02, 12 January 2009 (UTC)

Looking at our article, a vastly disproportionate number of pile ups seem to happen in North America (although that could be at least partially accounted for by our well known bias towards featuring topics from North America). I visited the US for Christmas and we drove from North Carolina to Florida and back and the standard of driving I saw did seem significantly worse than I see in the UK. Are Americans just really bad drivers? --Tango (talk) 01:50, 12 January 2009 (UTC)

Nothing is more American than tailgating, not using your turn signal, and talking on your cell phone while driving. Besides, speed limits are a guide for the absolute slowest you should be driving.</sarcasm>

Not having ever driven outside of North America, I couldn't give you an estimate as to how well drivers are compared to elsewhere in the world, but Americans do own more cars per capita than anyone else, so a high accident rate would not suprise me. I understand this is getting away from the OP's question, but just throwing my two cents in.-RunningOnBrains 02:26, 12 January 2009 (UTC)

I drive a Honda Civic but aren't Americans morely to drive bigger cars? I would imagine that heavier cars are harder to stop. A Quest For Knowledge (talk) 04:43, 12 January 2009 (UTC)

This is the incident in question, and it appears the snowy conditions contributed to the big pile-up. I don't know what kind of regulations they have in Massachusetts, but I gather that there is no mandatory use of winter tires -- at least this article on the topic seems to imply that while getting winter tires is a good idea, it's up to you. If that's indeed the case, I'm not at all surprised that cars can't stop in time; you can break all you want, but if you don't have traction, the car isn't going to just stop. Furthermore, if the drivers aren't experienced in driving under those conditions, that's going to compound the problem. Here in Finland the use of winter tires is mandatory throughout the winter months, and I believe one of the requirements for even getting a driver's license is a practice session or two on a slippery track, with snow and ice during the winter, and simulated conditions during the summer. It's not terribly difficult, but if a driver suddenly caught in snow and ice doesn't have any prior experience with trying to drive under those conditions with crappy summer tires that just aren't up to the task, things are bound to turn bad. I don't think a 50-car pile-up under conditions like that is the least bit surprising.

A pretty impressive example of snowy conditions with drivers who not only clearly don't have winter tires, but are also absolutely clueless as to how to drive on ice can be found here. I'm pretty sure the conditions on the Massachusetts freeway in question were nowhere that bad. Still, that video is enlightening; I'm kind of amazed by how these people lose control over and over again, smash into cars, and yet they step on the gas repeatedly. You'd think that after a couple of collisions they'd realize that what they're doing just isn't working... Luckily, no one seems to get seriously hurt in the video, as the cars are moving pretty slowly, but that's more luck than anything else. -- Captain Disdain (talk) 03:15, 12 January 2009 (UTC)

That youtube video displays the K5 logo of KING-TV of Seattle. I would bet that the roads being shown are very steep and hilly but it is hard to tell from the aerial viewpoint. The apparently accelerations are probably caused by cars sliding down hill rather than stepping on the gas. This isn't to say Seattle drivers are not poor winter-condition drivers--but there are extenuating circumstances, such as steep hills and repeating freeze-thaw weather that makes it harder than one might think. I grew up in Buffalo, famous for snow, and learned to drive on snow and ice there, then moved to Seattle. At first I thought it was absurd how bad Seattle drivers were when it snowed a little. Over time I came to realize how dangerous it can be to drive here after it snows. A few weeks ago we had some snow and I found that even with tire chains on our all wheel drive Subaru, one could not avoid sliding around at least a little, even on totally flat streets. That video looks silly and "clueless", but that kind of stuff can happen in Seattle even to drivers well experienced with winter driving. If nothing else, assume the roads in the video are much much steeper than they appear. Anyway, had to defend Seattle a little here! Pfly (talk) 08:40, 13 January 2009 (UTC)

Sure, clearly there's an incline: the cars wouldn't slip and slide and pick up speed like that otherwise (at 0:55 you can see an almost stationary car start sliding sideways). But if you think the driver at 0:06, and 0:09 isn't stepping on the gas -- despite the engine sounds that accompany the car's sudden changes in direction and acceleration -- I will have to respectfully disagree. (And that's after he had already hit at least one car.) I mean, I'm sure the conditions are exceptionally bad in this clip, but I'm also sure that if those people had proper winter tires, they would have a hell of a lot more traction, and if they knew how to drive in those conditions, a lot of those collisions would've been avoided. (The very first driver in the clip is the worst offender; he crashed four times. A part of knowing how to drive in conditions like this is knowing when you shouldn't...) -- Captain Disdain (talk) 16:14, 13 January 2009 (UTC)

That's Seattle. Nearly every street is on an incline, some of them quite steep, and they get snow maybe two years out of three. It's not surprising that people and cars aren't prepared for it. --Carnildo (talk) 22:55, 13 January 2009 (UTC)

Oh, something I forgot: a lot of this comes down to braking distance. I don't know how fast the cars were moving, but since it was an interstate, it strikes me as feasible to assume that the cars might have been traveling at nearly 50 miles an hour. Typically, the braking distance from 50 mph is about 30 meters. In crappy conditions like this, it may easily be twice that -- say, 60 meters, or about 200 feet. And that's assuming that the driver reacts instantly when something happens up ahead. At 50 miles an hour, if it takes you a second to actually start braking, in that time alone your car has traveled 20 meters, or over 60 feet, which is obviously going to be added to your overall braking distance. And if you're already slipping and sliding all over the place and trying to avoid crashing (or other cars that are on equally shaky wheels close by), or trying to see the road through snow that's still coming down -- for example -- things like that are probably not doing your reaction time any favors, either. What this means is that even if you're a careful, skilled and properly prepared driver yourself, that may not be enough, since even though you may be able to stop, the car behind you may not. You can get first hit from behind and then be pushed into the car in front of you. -- Captain Disdain (talk) 03:36, 12 January 2009 (UTC)

Note, the accident was in New Hampshire, not Massachusetts. Yes, the article you linked to does start off talking about students from UMass but they were traveling through NH on their way to Vermont. And to answer your inquiry, Captain, I've never heard of any state that requires snow tires in the winter months. Even here in Vermont we only have yearly inspections for the general safety of the vehicle. It does not include any provision as to the type of tire on the vehicle. And back on topic... Vermont, New Hampshire, and Massachusetts are rather hilly to say the least, so it's possible that the vehicles were on a downward slope to begin with. Also, some of those involved may have crested a hill only to find that there was nowhere to go but up their fellow driver's tail pipe! Dismas|^(talk) 05:15, 12 January 2009 (UTC)

Oh, New Hampshire. My bad! Teaches me to read properly, I suppose. -- Captain Disdain (talk) 05:23, 12 January 2009 (UTC)

Yesterday I watched a someone a few cars ahead of me drive into a traffic light poll because the conditions were so bad. There was no white-out, they could obviously see the light, they were just driving too fast for the conditions and couldn't stop. If the roads are bad I could see a 50 car pileup happening, especially on highways when people have to stop from 90km/h or more. -Pete5x5 (talk) 05:21, 12 January 2009 (UTC)

One thing which people seem to be forgetting that it's likely the case that some of the vehicles involved in the pile-up did stop in time. For example, it's easily possible the 49th vehicle stopped but war rammed by the 50th vehicle into the pileup. I.E. Remember that in any accident the only one you can resonably sure is at some fault is the one at the far back. Everyone else could be more or less innocent victims of the one at the far back (unlikely in a 50 vehicle pileup but definitely possibly in a 4 car one.) Also I'm not sure but when you have a 50 vehicle pileup does it automatically mean that all vehicles are touching? I suspect not. Therefore it's rather easy to imagine the 49th vehicle stopped well short of the vehicles in front but because the 50th idiot was tailgating and/or not paying enough attention they rammed the 49th who still didn't hit the car in front but would not be considered part of the pileup. If the 49th vehicle was a defensive driver and they knew they had more then enough time to stop they may have braked less hard if they'd felt the idiot at the back wouldn't stop in time but hardly a major fault Nil Einne (talk) 08:07, 12 January 2009 (UTC)

I slow down if somebody tailgates me and try to let them pass. I had somebody come too close behind a while ago when he road was slippery and so I slowed down, so they came even closer, so I was going along at 3 miles an hour or less for a while until I could find a space to let him pass. A complete klutz. Dmcq (talk) 12:56, 12 January 2009 (UTC)

This is actually just after the year anniversary of the 70 car pileup that happened on Interstate 4 in Florida Jan 9, 2008. In that case, fog and smoke mixed to reduce visibility to only a couple feet. A Year After I-4 Pileup

Winter tires?

In the above discussion, what exactly is meant by "winter tires" ? Does this mean studded tires or tires with chains ? I believe chains are actually illegal in many places in the US because they damage the roads. StuRat (talk) 05:29, 12 January 2009 (UTC)

Winter tires are tires that have a softer compound and more siping to grip the road better in icy conditions. They can be studded but many passenger cars tires are not studded. You'll often see this on plow trucks and various other work trucks. My friend has studded tires since he does construction and is often not on pavement because the driveway hasn't been put in yet. Check Nokian tires' web site for some pics. They sell a popular brand Hakkapeleeta or something like that. I can never spell it right... Here is a direct link. Dismas|^(talk) 05:35, 12 January 2009 (UTC)

You almost got it, it's Hakkapeliitta -- and "peleeta" is actually close enough to how it's properly pronounced, so all in all, you're not handling our monstrous heathen language badly.

A big reason some people prefer unstudded winter tires is that they make less noise, and some of them can be legally used round the year. Studs will definitely give you better traction, though. As for snow chains, they aren't generally in use in Finland, although they sometimes use them for snow plows and the like if the conditions are bad enough that the plow couldn't move without really heavy duty traction. It's pretty rare to see them on normal cars outside rural areas, but they aren't illegal (though I guess some models of them may be, as the law requires that the snow chains must be of a model that doesn't do "significant" damage to the roads). -- Captain Disdain (talk) 05:53, 12 January 2009 (UTC)

Snow tires degrade much faster than all-season tires during warmer temperatures, so it's generally not a good idea to leave them on all year round, unless you live in a very cold place. I know that in many places in Canada (southern Ontario at least) tires with any type of studs or chains are illegal, and yet in some other parts where there are many less traveled roads (northern Ontario and the more northern provinces) I think it's the law to have chains with you. -Pete5x5 (talk) 06:26, 12 January 2009 (UTC)

Similarly, starting this winter drivers anywhere in the province of Quebec are required by law to use winter tires during the winter. (I suppose visitors from outside Quebec are exempted, but I don't know.) There were news reports about how many peopel had left it until the last minute to get them, with predictable results at the tire stores. It's too soon to know, but they were hoping for a significant reduction in accidents. --Anonymous, 06:35 UTC, January 12, 2009.

Winter tires will generally display the Mountain/Snowflake Pictograph. -- Coneslayer (talk) 12:53, 12 January 2009 (UTC)

Tailgating is not just common in the US - it's institutionalised! The Texas driver handbook (and a recent TV ad from (of all people) an insurance company) say that you should stay "two seconds" behind the car in front. So as the car in front passes some kind of distinctive feature - start counting seconds: "One pink aardvark, Two pink aardvarks" and you should NOT yet have passed that same point on the road before at least 2 seconds has elapsed.

HOWEVER: In at least the UK and France the no-tailgating rule is known as "the three second rule"...so you have to wait for a THIRD pink aardvark. Having been brought up on the three aardvark second rule - I habitually leave that much space - and STUPID AMERICANS keep sticking their cars between me and the guy in front. Perhaps they do this fondly imagining that since they have a two second gap between them and the car in front - they did an OK thing...completely forgetting that they left me with a razor-thin <1 second gap! So either I have to repeatedly slow down to leave an new 3 second gap - or I have to take a deep breath and drive with a less than 2 second gap all the time. Worse still - the insurance companies have adopted a rule-of-thumb that in the event of a rear-ending, the car at the back is deemed to be "at fault"...which could not be further from the truth when someone cuts you up like that - then has to brake suddenly.

US road & traffic laws are unbelievably stupid. Argh!

SteveBaker (talk) 14:33, 12 January 2009 (UTC)

If you're counting pink aardvarks as you drive, you need to stop the car until you've sobered up. :-)

I agree both on the tendency of people to pull in front of you if they feel you have too much of a gap in front, and the stupidity in just assuming the car in back is always at fault in any accident, but US insurance laws are made to benefit the insurance companies, not US citizens, and simple but stupid rules like that make handling claims much easier and less expensive (they, on average, would pay as much either way, but can avoid expensive court fights to determine fault this way). I just drive around in reverse all day, so that any car I ram will be blamed for hitting me in the back. :-) StuRat (talk) 16:44, 12 January 2009 (UTC)

Blood Diseases.

What is Haemeachromatosis?202.161.70.74 (talk) 02:15, 12 January 2009 (UTC)

I suspect it is a misspelling of Haemochromatosis.-RunningOnBrains 02:16, 12 January 2009 (UTC)

Or a misspelling of hemochromatosis. :) - Nunh-huh 02:43, 12 January 2009 (UTC)

White metal?

I was cleaning my stovetop today, and I was struck by the fact that the surface appears to be a shiny white metal. Maybe the color is just a coating, but if so it is a very durable one that can resist things like heat and scouring pads. My impression though is that the color is the actual color of the material that the stovetop was constructed from. Shiny white seems to be a fairly unusual color for a metal (as opposed to silver or gray), so I'm curious, what material is this likely to be and how common is it? Dragons flight (talk) 02:34, 12 January 2009 (UTC)

We have an article, white metal, that discusses the kinds of metals that go into very light coloured alloys. It talks about jewellery, rather than stoves, though. --Tango (talk) 02:57, 12 January 2009 (UTC)

Are you sure the stovetop is metal rather than a white glass-ceramic stovetop? I would suggest googling the brand of stovetop you have to be safe. 152.16.15.23 (talk) 02:59, 12 January 2009 (UTC)

I suspect it will just be a layer of enamel paint. If you scratch it deeply enough, you'll find the shiny steel underneath. The paint is thick and tough enough to withstand a lifetime of ordinary scouring.-gadfium 03:05, 12 January 2009 (UTC)

On a stove it would rather be enamel rather than enamel paint. The latter may be used on fridges and other appliances that are not exposed to high temperatures. True enamel is powdered glass (sort of) that is baked onto the (metal) surface at 1,500-1,600 F The powdered material melts and produces a hard surface coating. Scratching it off your stovetop would only cause irreparable damage (Enamel touch-up paints are not for use on stove tops for the same reason they don't use enamel paint on them.} If you look at an edge though like e.g. at a burner hole you might see some metal underneath. If you really are after causing damage, chipping or cracking the material works better than scratching. (OR the edge of a heavy pot will do.) white used to be the standard for appliances. (They even used to be called "white goods" in some places.)--76.97.245.5 (talk) 04:58, 12 January 2009 (UTC)

As an aside, major appliaces are still known as whiteware in NZ and I believe Australia. See for example [1] [2] [3] Nil Einne (talk) 07:56, 12 January 2009 (UTC)

Must be just a Kiwi thing, i've lived in Australia since I was a kid (25+ years) and I've never once heard it called "whiteware". Vespine (talk) 03:31, 14 January 2009 (UTC)

If a magnet sticks to it, it is sheet steel with some kind of coating. – GlowWorm. —Preceding unsigned comment added by 174.130.253.174 (talk) 05:53, 12 January 2009 (UTC)

This

How is Avobenzone formed? What is the science behind Avobenzone? What is it's occurrence in nature?96.53.149.117 (talk) 03:07, 12 January 2009 (UTC)

Why the continual reposting of this query? Please see the response to your Jan. 7 post, above or in the archives. -- Flyguy649 ^talk 03:22, 12 January 2009 (UTC)

Benzophenone

How is Benzophenone-9, Benzophenone-3, Benzophenone, etc. formed? What is the science behind Benzophenone-9, Benzophenone-3, Benzophenone, etc.? What is it's occurrence in nature?96.53.149.117 (talk) 03:25, 12 January 2009 (UTC)

Have you read Benzophenone? Algebraist 03:28, 12 January 2009 (UTC)

No, sunscreen is the relevant article. Cacycle (talk) 04:57, 12 January 2009 (UTC)

ICOS or Icos?

I'm editing an article on ICOS, the U.S. biotech company acquired by Lilly, but I'm unsure about the capitalization. Many documents say ICOS, but many other documents, like newspapers, say Icos. The article previously had ICOS, but today I changed everything to Icos, seeing the newspaper articles, and the fact that it's a shortening of icosahedron. But now I'm having doubts. A friend who was an employee says that higher-ups told him/her it was ICOS. Which is it? Thanks for your help! Shubinator (talk) 04:05, 12 January 2009 (UTC)

If you search the Lilly site [4] it seems to be "ICOS". I guess they would be a reliable source. --Scray (talk) 05:03, 12 January 2009 (UTC)

Per WP:MOS-TM, names should generally be written in the fashion preferred by other English authors, and not necessarily in the fashion preferred by the company itself. This avoids drawing special attention to specific companies just because they indulge in excess capitalization of gimmicky formatting. Based on what I see, "Icos" is probably the correct approach. Dragons flight (talk) 05:32, 12 January 2009 (UTC)

The newspapers themselves have both versions. For example, this article from the New York Times and this article from the Seattle Times both have "ICOS". Shubinator (talk) 16:43, 12 January 2009 (UTC)

Thanks for everyone's help! I'll keep everything at "Icos". Also, I've asked for the ICOS page to be moved to Icos with the db-move template. The Icos page had two revisions in its edit history. (If there are any admins reading this, can you do the move?) Shubinator (talk) 02:05, 13 January 2009 (UTC)

cannibis

In what ways is everyday use of cannibis benefitial/harmful to overall mental and physical health? —Preceding unsigned comment added by Shschrgrs (talk • contribs) 05:20, 12 January 2009 (UTC)

Have you read the cannabis article and followed the various reference links? Dismas|^(talk) 05:29, 12 January 2009 (UTC)

It causes the biuld up of tar in the lungs (like cigarattes) and it reduces sperm count.--Apollonius 1236 (talk) 03:16, 13 January 2009 (UTC)

Unless you're joking, provide references. This is the reference desk afterall. Also the cannabis (and related) articles contain way more information than could be replicated here. --Mark PEA (talk) 17:16, 13 January 2009 (UTC)

Torque

I can't grasp why increasing the distance from the axis of rotation that a force is applied will increase the angular acceleration. I understand the usual explanation given by work, but this involves the assumption that work applied by the force and the work experienced my the rotating object must be the same. Is there to derive this property of torque someother way, like through newton's second law?

OK - so we have a bicycle wheel and a piece of string. We tie the string to a spoke and slide the knot to the outer edge of the wheel - then pull on the string at a right angle to the spoke (ie: at a tangent to the circumpherence of the wheel). The outer edge of the wheel has to move at the same speed as the string - so the linear position, speed and acceleration of that point on the outer edge of the wheel are all equal to the position, speed and acceleration of the end of the string. If you pull the string one centimeter - the outside of the wheel moves one centimeter (duh!) - if you pull the string one centimeter in one second, then the velocity is 1cm/s and if you accelerate the string at 1cm/s² then that point on the wheel does the same. The small angle the wheel turns through when the string moves 1cm is: (simple trig!) arctan(1cm/r) - where r is the radius of the wheel. The angular speed and acceleration in radians per second or radians per second squared is just the same deal: arctan(v/r) and arctan(a/r) respectively. Slide the string inwards along the spoke towards the middle of the wheel - the radius gets smaller and 1/r gets bigger so v/r and a/r both bigger and so are arctan(v/r) and arctan(a/r). Hence, the angular velocity and acceleration increase with decreasing radius. Weird - but true!

The "work done" is equivalent to "energy expended" - and the energy doesn't just disappear because you converted it to angular acceleration...so the argument from the perspective of "work done" is perfectly valid. I'm sure you could do the same thing through Newton's laws - but the geometric argument (above) is much easier to follow IMHO.

SteveBaker (talk) 12:14, 12 January 2009 (UTC)

Isn't it the other way around-doesn't angular acceleration decrease with decreasing radius? :S

Er wait a minute...for constant what exactly? For constant energy input? For constant linear velocity? I was kinda assuming the latter. I guess not. Well now you've confused me! SteveBaker (talk) 16:00, 12 January 2009 (UTC)

Consider a see-saw. People sitting on one side rotate it in one direction, and those on the other side (who are also pushing down, of course) rotate it the other way. (The fulcrum in the middle applies different forces depending on where you push.) The effect varies continuously with the location of the force, so a force at the center accomplishes nothing and a force near the center has little effect. It would be strange if it were otherwise: if you are sitting on the end of one side and your twin is halfway along the other, and the effect did not depend on the distance, we would expect the see-saw to be balanced. But now consider your seat as the pivot: the real fulcrum must be holding both of us up, but only the twin is holding it down, so it should (since the distances don't matter!) pivot upwards away from you. In other words: if distance doesn't matter but which side you're on does, we can produce contradictions like this one by changing the definition of "side". --Tardis (talk) 19:08, 12 January 2009 (UTC)

I know from experience that it must be true, but im wondering why. and as for steve's confusion, im just wondering why it is torque is proportional to the radius from which the force is applied-and im sorta looking for an explanation other than because work is constant. —Preceding unsigned comment added by 65.92.5.109 (talk) 21:29, 12 January 2009 (UTC)

It's just a convention really. It allows us to create simple rotational analogues of the equations of linear dynamics - for example, work = force x distance becomes work = torque x angle and power = force x velocity becomes power = torque x angular velocity. To create an analogue of Newton's second law we have

force = mass x acceleration

=> torque = mass x radius x acceleration = mass x radius² x angular acceleration

which then leads us to identify the quantity mass x radius² (or moment of inertia) as the rotational analogue of mass. Gandalf61 (talk) 10:43, 13 January 2009 (UTC)

Copolovian Mischief

I a recent brodcast on medical malpractice on teh NBC I heard Dr.Smith talk of COPOLOVIAN MISCHIEF!!I remeber reading about this in NYT also a few months agao.Googling did not give me any joy.Does anybody know what it is?

"Coppolovian" (with two P's) maybe? As in Francis Ford Coppola? Perhaps this in reference to the kinds of movies he makes? Maybe "The Godfather" and sequels? It's a wild guess I'm afraid. Perhaps it would be more obvious if we had a little more context about the nature of the malpractices he's talking about. SteveBaker (talk) 13:58, 12 January 2009 (UTC)

RULE #1 of Wikipedia Reference Desk question answering: When the OP says "I tried Googling it and got nothing" - just go ahead and Google it anyway:

Argh! Strike my previous answer. Are you COMPLETELY SURE you tried Google? Because I just typed "Copolovian" into Google and the third hit was: http://copolovianmischief.rediffblogs.com - which says right in the first paragraph (and in the Google summary!):

"Copolovian Mischief is a term applied to Machiavellian duplicity,powerplay,conspiracy,dishonesty and medical deceit practiced by unscruplous medical practitioners.It is named after David Copolov an Australian psychiatrist."

We don't have an article about Copolov - but his name does crop up in a few places as an author of books on subjects relating to psychosis and schizophrenia. He was the Australian Drug Evaluation Committee’s psychiatric expert from 1992 to 2000...but seems to have 'gone off the rails' in attacking another researcher...urgh...messy business - read the link I gave you for all of the sordid details. SteveBaker (talk) 14:12, 12 January 2009 (UTC)

Not only that but the blog has been there since 2005. Nil Einne (talk) 09:05, 13 January 2009 (UTC)

BTW, I wouldn't trust that blog too much. David Copolov appears to remain a respected professor [5] [6]. And for some of the flipside see, [7] [8]. Also it appears aspects of the controversy have hit wikipedia Wikipedia:Articles for deletion/Ashoka Jahnavi-Prasad and Wikipedia:Suspected sock puppets/Vr. Per BLP, I'll refrain from speculating about the individuals involved but suffice to say, it's unlikely the blog is telling the whole story (which doesn't mean Copolov is necessarily completely innocent) Nil Einne (talk) 09:29, 13 January 2009 (UTC)

And I think we have another one here...Nil Einne (talk) 09:43, 13 January 2009 (UTC)

Good point. Well, whatever the truth or fiction of the story - and irrespective of whether Copolov really did violate medical ethics or not - this is undoubtedly the etymology of the term our OP is asking about...and that's all that really matters in answering the question. SteveBaker (talk) 16:18, 13 January 2009 (UTC)

Another help would be the show - or even the time of day that the show came on. Then, we could check the transcripts. I have no interest in going through every transcript for every show on NBC in the last six months just to see what you could have possibly misheard as "copolovian". -- kainaw™ 14:01, 12 January 2009 (UTC)

For anyone reading the archives, bear in mind this question was asked by a sockpuppet with an apparent fascination with Ashoka Prasad and I doubt the blog in question really appared in NBC or NYT particularly as it has no Google results other then the blog itself and this. I suspect RNaidu was well aware of the blog and what he/she was referring to before they asked the question, which was why they 'didn't' find it from 'Googling'. Nil Einne (talk) 11:07, 22 January 2009 (UTC)

Look at this link again:

[9]

The venom against colour

I read with interest the news item on the Indian High Commissioner’s dealings with the Australian authorities. I was a student at Deakin University in Victoria in the 80s, spent three years there, and am in a position to know the problem of racism in Australia. It has persisted over the decades with the authorities burying their heads in the sand! After all, we all remember the Ozzie reaction when it followed a white-Australia policy and when a legislator made that infamous comment ~ “Two wogs do not make a white”.  

And do I need to remind everyone that the self-confessed racist, Joh Bjelke-Peterson, nearly became the Prime Minister in 1987? Bruce Ruxton of RSL made a career out of spewing venom against people of colour and was a popular figure in Melbourne. And Dennis Lillie never minced his racial prejudices. We were all shocked when David Copolov and John Funder indulged in a shocking display of racism which came to be infamously called as Copolovian mischief in order to malign one Mr Prasad, an Indian colleague. Mukesh Haikerwal’s rise to the presidency of the Australian Medical Association did not prevent him from being beaten up by racist thugs. And I have not forgotten Darren Lehmann’s words in an ODI. It is high time some concrete steps were taken.

Seema Biswas, London, 13 February.

A question on gravity

[Question copied from Gravitation talk page.]

I was studying string theory, and a chain of effects were set into motion leading all the way back to gravity, when a concept dawned on me - Gravity is traditionally thought of as a force that pulls objects together, thus people and objects are pulled towards Earth as Earth is pulled towards the sun. However, if such a pulling force were to exist then wouldn't it cause these objects to pull in towards eachother, causing planets to collide with the sun? I realize this question may sound simplistic to physicists but I am lost. Thanks! 71.54.120.113 (talk) 03:16, 12 January 2009 (UTC)

It is indeed true that if an object A pulls on object B with a particular force, then object B will also pull on object A with exactly the same force. This is just what Newton's third law of motion says. However, unless the objects are moving pretty much directly towards each other to start with (or sufficiently slowly directly away from each other), they will not necessarily collide. In the case of the gravitational force, whose size varies as the inverse square of the distance separating the bodies, the two bodies will either perform elliptical orbits about their center of gravity, or recede from each other indefinitely along parabolic or hyperbolic paths.

In the case of the solar system, the Sun is so much more massive than any of the planets that the attractive forces between the planets themselves is negligible in comparison, and the force exerted by each planet on the Sun doesn't move it very much (even though the size of that force is the same as the size of the force exerted on the planet by the Sun). The ratio of the tangential velocities to the radial velocities of most of the planets is of such a size that they orbit the sun in elliptical paths with very small eccentricities (i.e. paths which are very nearly circles).

—David Wilson (talk · cont) 11:57, 12 January 2009 (UTC)

Imagine a cannon firing a cannonball exactly horizontally - parallel to the surface of the earth - with the mouth of the cannon being (lets say) one meter above the ground. The cannonball shoots out - and gravity pulls it gradually towards the ground until it's dropped by one meter and it hits the ground...right? Well, yes - but the earth is curved so if you fire the cannon with a bit more gunpowder so the ball moves faster - the curvature of the earth will mean that the ball has to fall a bit more than 1 meter to hit the ground because the ground has curved away beneath it. If you fire the cannonball still faster, the earth may have curved away by a few kilometers and it'll take a LONG time for the ball to fall that far and hit the ground. If you fire the cannonball fast enough, the earth will curve away from it at exactly the rate it's falling and it'll NEVER hit the ground! In fact, it's in orbit. In that case, the centrifugal force due to the cannonball moving in a circle EXACTLY matches the force of gravity - the two cancel out and the cannonball orbits forever. That's why all of those satellites stay up there in orbit and don't fall back to earth. It's also why the moon doesn't fall down and crash into the earth...and why the earth (in orbit around the sun) doesn't fall back into the sun. Orbits. SteveBaker (talk) 12:34, 12 January 2009 (UTC)

(And lest one think the cannon metaphor is a stretch, see Project HARP) --140.247.236.243 (talk) 21:21, 12 January 2009 (UTC)

I was thinking of Project Babylon - which was Saddam's space gun. A section of that beast is in the Imperial War Museum in London - I was there installing some other equipment when it arrived after being intercepted en-route to Iraq and saw the curators struggling to get this monsterous chunk of metal out of the packing case so they could put it on display. That gun would have been a simply incredible thing! SteveBaker (talk) 21:49, 12 January 2009 (UTC)

Temperature

Is there a theoretical upper limit to temperature, such as the lower limit? I understand why it's possible to have a lower limit since the kinetic energy of particles can drop to zero, but I'm not sure if there's a kinetic energy too high for particles to achieve without an infinite amount of energy. —Cyclonenim (talk · contribs · email) 13:03, 12 January 2009 (UTC)

Well it depends on what you mean exactly by "without an infinite amount of energy". Theoretically a particle can have kinetic energy tending to infinity. So, in this sense you could imagine some kind of ideal gas of particles, each with an infinitely large kinetic energy and corresponding temperature. However, if you are looking for the highest temperature possible without an infinte amount of energy, it's all going to depend on the largest amount of energy you are allowing the system to have. 163.1.176.253 (talk) 13:36, 12 January 2009 (UTC)

What gets complicated is that temperature is only really a property that means anything at 'human scales' - down at the atomic level, temperature is related to "kinetic energy" - the square of the speed at which particles are jiggling around multiplied by their mass. So as you pump in more energy - at our level of experience, things get "hotter" - but at the lowest levels of existence, they get faster. OK - so this starts to sound like a question about the upper limits of speed. We know what that is - right? It's the speed of light. So the highest temperature anything can be when all of the atoms are moving at the speed of light. However, when things start moving around close to lightspeed, all of the wierdnesses of special relativity kick in. So as you try to push atoms to move faster ("get hotter") they'll eventually start to reach relativistic speeds - and when that happens they get heavier. In fact the faster you push them, the heavier they get so that the amount of energy it takes to make the atoms get just a tiny bit closer to the speed of light goes up exponentially. So, no matter how much energy you put in - they'll never get to the speed of light - they'll just get so heavy that you can't move them anymore. Hence - there is a limit to their speed - but no limit to their mass. Since kinetic energy is velocity-squared times mass - even though the velocity is limited to not-quite-the-speed-of-light - the mass can become infinite - so in principle, there is no limit to the temperature something can be. Ultimately, there is a limit - but it's not a limit on how hot it COULD be - it's a limit on the amount of energy available to make it hotter. I guess you could imagine taking all of the matter and energy in the entire universe - except for one hydrogen atom - turning it ALL into energy - then using that energy to push that one hydrogen atom up to 99.99999999...(lots more nines)...99999% of the speed of light - and that would be the ultimate limit. But you'd have to destroy the entire universe to do it - so that's definitely an experiment that only the most evil of evil geniuses would consider performing!

SteveBaker (talk) 13:53, 12 January 2009 (UTC)

For certain types of systems with a finite number of accessible states, the upper limit is -0 K (yes, that's negative zero). Dragons flight (talk) 14:02, 12 January 2009 (UTC)

(ec) Per the anonymous poster, you need to be working in a system where there is a meaningful upper limit to the average kinetic energy of a particle. In statistical thermodynamics, the temperature and kinetic energy of a system of ideal particles are governed by the relationship

E = 3/2 N k_B T

where N is the total number of particles and k_B is the Boltzmann constant. In principle, you could assign a temperature to any particular particle by rearranging the above relationship to solve for T. To get an absolute upper limit for temperature, you could take an estimate of the total amount of energy available in the Universe and plug it in. (Put all the available energy into one particle, and it will be the hottest thing you can get.)

In practice, of course, trying to pack all that energy into a single particle is not going to be a stable situation. (The last time we put all the energy of the Universe into a small package, we got the Big Bang.) At much more modest particle energies – a few MeV, corresponding to temperatures of a few tens of billions of kelvins – there is a tendency for particles to lose energy by converting it to new particles. This is the fundamental mode of operation of particle accelerators like CERN's Large Hadron Collider.

At high energies, relativistic considerations also come into play. As the relativistic mass of the particles increases, they have a nasty habit of collapsing into tiny black holes. (See our article on Hawking radiation for a method to calculate the apparent temperature of a black hole.) TenOfAllTrades(talk) 14:17, 12 January 2009 (UTC)

Thanks for all your responses, that clears things up a fair bit :) Cheers. —Cyclonenim (talk · contribs · email) 14:49, 12 January 2009 (UTC)

I've read that when supernovae get to a certain temperature, they start emitting neutrinos rather than photons. Since they don't reabsorb the neutrinos like they did the photons, they will cool down a lot faster than they can heat up, so they just stay at that temperature. Because of that, it's the hottest anything is likely to get. Does anybody know what that temperature is? — DanielLC 20:36, 12 January 2009 (UTC)

There is a temperature, the Planck temperature, above which modern science cannot describe physically due to shortcomings involved when general relativity and quantum mechanics meet up. It is approximately 1.41679(11) × 10³² Kelvin. -RunningOnBrains 02:17, 13 January 2009 (UTC)

Supersonic wind?

I'm currently doing my best to exasperate the principal editors of "Neptune" (copyedit, that is), and I ran across reference to "near-supersonic winds". Smoke started coming out of my ears. Can a medium of sound be said move at supersonic speed? And when we say "supersonic" in such a context, speed of sound in what? And if a tree falls in a supersonic wind, does it make the sound of one hand clapping? --Milkbreath (talk) 14:17, 12 January 2009 (UTC)

Um - I think it's possible for it to be meaningful - but I guess it tells me very little about how fast the wind is because I don't (offhand) know the speed of sound in the Neptunian atmosphere's particular temperature, pressure and chemical composition. Hopefully they aren't taking about "near earthly-supersonic speeds"...ie close to 720mph?!? But this is an encyclopedia, not a popular science show. We shouldn't say things like "thinner than a human hair" or "longer than a football field" - we should provide numbers. So why not just state the actual wind speed in kph or m/s with the mph number in brackets afterwards (with a reference or two) and dial-down the sensationalism and rhetoric? This is more an issue about how you write for an encyclopedia than it is a matter of science. SteveBaker (talk) 14:40, 12 January 2009 (UTC)

Sorry, they do give a speed of "nearly 600 m/s", which is almost twice the speed a regular person means when he says that. And I do mean to stomp that sentence into the dirt. It's just that I'm having trouble getting my head around a medium moving faster than sound does in it. If you hit an F-15 in the tail with a hammer while it's going Mach 1.5, does the sound get to the nose, or is it the other way around? --Milkbreath (talk) 15:08, 12 January 2009 (UTC)

It's all relative. Sound always travels at the speed of sound in the medium with respect to the co-moving reference frame. If one says the medium itself is moving, then one has implictly or explicitly chosen some other external reference frame by which to measure. For example, a wind could hypothetically be moving at supersonic speeds with respect to the ground. Within that wind though, sounds continue to propogate relative to the inertial frame of the wind. Dragons flight (talk) 15:20, 12 January 2009 (UTC)

I guess if some of the air is stationary - and then (off to the side a bit) the wind blows a little localised gust - then it would seem like an entirely reasonable statement - but when the entire atmosphere is rotating with respect to the surface of a planet - it would be a different matter. I dunno - if you've said what the speed is - in units people can relate to (Miles per hour, Kilometer per hour - probably not meters per second) - then you've said what needed to be said. Muddying the waters by adding "nearly supersonic" is just SO unencyclopeadic...especially because the speed of sound in Neptune's atmosphere is a complete unknown to 100% of people who are likely to be interested in that sentence. You should definitely strike that clause on those grounds alone. SteveBaker (talk) 15:57, 12 January 2009 (UTC)

I agree in this particular case that the comparison with the speed of sound isn't good, but don't agree that, in general, we need to avoid phrases like "thinner than a human hair". If listing something like the diameter of a fiber optics cable results in a value that the average person can't relate to, it's quite reasonable to list the comparison with a human hair, or other easily recognized reference point, in addition to the actual numbers. I've even seen scientific journals that do similar things, like putting a penny in a pic of a computer chip to get a sense of scale. StuRat (talk) 16:25, 12 January 2009 (UTC)

I would disagree with it being useless. Yes we should have the actual numbers there too, but saying the speeds are "near-supersonic" tells you something about the fluid flow; you're going to have to treat it as a compressible fluid which behaves differently to an incompressible fluid. 79.66.104.50 (talk) 19:44, 12 January 2009 (UTC)

Eh? Not if the whole atmosphere is rotating bodily. SteveBaker (talk) 21:44, 12 January 2009 (UTC)

Nowhere does it say the whole atmosphere is rotating at these speeds; it's talking about storm systems. 130.88.52.62 (talk) 16:06, 13 January 2009 (UTC)

I'm now glad I asked about this. The links 79.66 provided let me off the hook—anybody who can write that "information about conditions downstream...cannot propagate back upstream" is more confused than I am. I and 79.66 have changed it so it makes sense now, I hope. Thanks all. --Milkbreath (talk) 00:24, 13 January 2009 (UTC)

Immunofluorescence

Hello! I really would appreciate it if someone could explain how to avoid false positives and false negatives when studying Immunoglobulin M by means of immunofluorescence. I've got an exam soon and I can't find the info anywhere. Thank you a lot to anyone whi can help

You need to provide more information to get a meaningful answer. Where is the IgM that you want to study located? In the membranes of B lymphocytes, as part of the B cell receptor? Intracytoplasmatic? Bound to antigens on cells? Are you working with cells in suspension or tissue sections or something else? What to you want to find out about your IgM? Whether it's there or not? Quantitative information? Its specificity? Anyway, some general advice: wash whatever material you're working with before adding fluorochrome-labeled anti-IgM, to remove soluble IgM. Failing to do so may result in a false negative reaction because your anti-IgM would react with the soluble IgM. If you want to measure intracytoplasmatic IgM, you need to permeabilize your cells. Depending on the assay, you may need to wash also after the reaction with labeled anti-IgM has taken place. And include the relevant controls. --NorwegianBlue ^talk 19:41, 12 January 2009 (UTC)

Controls. Axl ¤ [Talk] 20:32, 13 January 2009 (UTC)

LED light bulbs dimmable?

I just bought a fancy LED light bulb (40W of light for 1.5W of power with a crazy 36,000 hour lifespan). On the back of the package there's a warning not to use it with dimmers, automatic timers, or motion detection lights. It's the same warning on CFL bulbs. I can understand not using a dimmer on CFL lamps, but LEDs? --70.167.58.6 (talk) 21:30, 12 January 2009 (UTC)

Yes - they are correct (that's also true for CFL's). You can dim down an LED but not simply by dropping the voltage - you have to turn them on and off really quickly and rely on persistance of vision to make it look like they are dimmer. I presume the reason that simply reducing the mains power doesn't work is because there is all sorts of circuitry inside the "bulb" that drops the power down to the right voltage and such like. As the world switches over to LED's - we're going to need some better infrastructure in our homes. I have a (hugely expensive) Red/Green/Blue LED light which you can not only dim - but also alter the color to absolutely any color you can imagine. However, to make it work you have to have in internet connection to the computer inside the light! That's not such a stupid idea - for lots of reasons - but if your house isn't wired up that way - it's a major pain. It's probably going to wind up that things like lights will get their power from the wall switch but use WiFi connections for things like dimming, color shifting and turning lights off when the last person leaves the room. We are about to enter a whole new era with this stuff. SteveBaker (talk) 21:42, 12 January 2009 (UTC)

Have you done the math on how many centuries it would take for that type of light to pay for itself ? StuRat (talk) 22:37, 12 January 2009 (UTC)

It's hard to imagine a real need to implement such bulbs on a large scale. Somehow I doubt expensive LED lights that need WiFi to adjust are going to be the future of most people's interior lighting. --98.217.8.46 (talk) 22:54, 12 January 2009 (UTC)

It doesn't have to cost that much. Remember - it's using about 5% of the electricity of a conventional bulb and it'll last (essentially) forever. You can do short range WiFi and a TCP/IP stack for under $5 these days...if you sell enough. Also, I don't want that sophistication in every room in the house - so most bulbs can be completely dumb LED's. But in areas of the house where I've spent a small fortune on decorating nicely and having nice antiques and a big-assed TV screen - to spend a little extra to light it nicely is a small price to pay...and having lights turn off automatically when you leave the room would be a significant energy saving. On the other hand, the light that comes on in my closet when I open the door isn't likely to ever need to be dimmable, color-settable or anything else. SteveBaker (talk) 23:02, 12 January 2009 (UTC)

The LED light assembly must already have a lot of silicon circuitry to work at all: this includes all of the expensive parts of a microprocessor: I/O, interfaces, power suppies, and connectors. The incremental cost for just the intelligence, in high volume, is certainloy less than a dollar. For a new install, the cost of the intelligence will be less than the savings in copper you would get by running 24AWG control wiring to the switches instead of 14AWG power wire. for a retrofit, the extra functionality justifies the low absolute cost. Note that I am assuming wired control via the existing wiring: it's cheaper and more reliable than WIFI. -Arch dude (talk) 02:21, 13 January 2009 (UTC)

An LED is directly dimmable by 2 means. 1)(My favorite:) reduce the DC current flowing through it. 2) Keep the current constant, but reduce the duty cycle. Compact fluorescent bulbs are made in non-dimmable and dimmable versions, The dimmable bulbs cost nearly 3 times as much. If a non-dimmable CFL is connected to a dimmer switch and it is turned down, the bulb fails and cannot be made to light afterwards. There are now on the market LED screw-in light bulbs. I discount the teaser ones which are the equivalent of a night light, and consider the one which produces the light of a 100 watt incandescent bulb, while using less electricity than either an incandescent or a compact fluorescent bulb. At this early stage, such bulbs sell for about $80 (U.S.) to $100 (U.S.) for a 100 watt equivalent. They only draw 13 watts and have a projected 50,000 hour lifetime. Such a bulb might fail if placed on a dimmer circuit. But because such bulbs have electronic circuitry in their controls, it should be simple to provide a means of dimming it by various means, including wireless remote control, or a brightness code controlled by turning it on and off, or even brute force brightness control by Variac or electronic dimmer switches. The Evolux R allows outout of 250, 750 or 950 lumens by rapidly switching it on or off. Compatibility with dimmer switches should be quite easily attainable by clever designers if you want continuous gradations of brightness without the annoying switching on and off. Toshiba offers a dimmable LED bulb (E-60, equivalent to a 60 watt incandescent, but drawing only 6.8 watts) for $350. Imagine a world where a burglar breaks into your house, ignores the flat screen TV and silverware, and steals all the 60 watt light bulbs. I suggest waiting a few years until market pressure drives the prices down from these ripoff levels. Edison (talk) 03:20, 13 January 2009 (UTC)

Yep - I agree, they are not much more than gadgets for geeks and tree-huggers at this point - but there can be no doubt that they are the future. CFL's are at best a short-term fix - if for no other reason than the mercury inside. What makes LED lighting so expensive is that LED's run best on about 5 volts DC - and 110v AC (or worse, 240v AC) means that there is a bunch of circuitry doing power conditioning. If we were building from scratch, it would probably make more sense to do things differently - maybe use 12v for lighting circuits and provide a separate 'control' signal. But whoever breaks into the market with these things isn't going to be able to do it by selling only to new home builders. So whatever we have will end up being reverse-compatible with existing bulbs - and therefore horribly sub-optimal. That's why I suspect we'll start seeing control signals sent via WiFi. Sure it's going to cost a little more - but it's nothing compared to the cost of getting an electrician in to pull cable. The scenario where a burglar breaks in and steals the light bulbs is not so far-fetched. I run the Mini Owners of Texas car club - and we've seen a rash of people wrecking the metalwork on the fronts of MINI Coopers in order to get the headlamps out - they do thousands of dollars worth of bodywork damage to a beautiful new car - just to steal a pair of $50 headlamps. It's heartbreaking. SteveBaker (talk) 05:34, 13 January 2009 (UTC)

oh you run the Mini Owners of Texas car club now do you? A few days ago you lived in Poland. Before that, you had an advanced degree in information theory or somesuch. I think you write whatever is most convenient at the time. —Preceding unsigned comment added by 82.124.85.178 (talk) 13:14, 13 January 2009 (UTC)

Oohh! Nice violation of WP:NPA! Well, let's see I don't think I ever claimed to live in Poland...I live in Texas, actually. I have a degree in Cybernetics (with the University of Kent) and Information Theory is indeed a big chunk of what Cybernetics covers. Feel free to go to the http://www.MiniOwnersOfTexas.org web site - click on the "You can contact our webmaster here." link and see if it really does send email to the same email address that you'll find at User:SteveBaker - when you do that, you'll be able to send your profuse and heartfelt apologies to me directly. You could also check the IP address of my own web site (linked from my User: page) and compare that to the IP address of www.MiniOwnersOfTexas.org site and...oh...guess what...they are on the same computer! Believe it or not, it is actually possible to hold a degree and run a car club at the same time. And yes - if I have expertise or practical examples that help - then I do endeavor to write whatever is most convenient (and, above all, TRUE). SteveBaker (talk) 16:10, 13 January 2009 (UTC)

As with most long term RDers, I would have to come to SB's defence here. He has frequently mentioned his involvement in Minis, that he is British but lives in Texas and that he works as a programmer in an interesting variety of jobs. I don't recall reading about his degree until recently but given his work it didn't surprise me when I read about his degree. Also his user page User:SteveBaker has mentioned most of this for a long time [10]. I've never heard him claim he's Polish so I'm guessing your thinking of the wrong person. He does have a French wife I believe Nil Einne (talk) 21:56, 13 January 2009 (UTC)

Nie mam polskiego. SteveBaker (talk) 23:12, 13 January 2009 (UTC)

Why would they tell the user not to use the bulbs with an automatic timer or motion sensor? --Sean 13:42, 13 January 2009 (UTC)

I was wondering that myself. I'd guess that some such devices occasionally provide reduced voltage (right around when they switch, for example), which is bad for the LEDs. I've seen motion sensitive switches that bring the lights right on but then slowly fade off, for example. StuRat (talk) 14:10, 13 January 2009 (UTC)

Wouldn't it make more sense to put all the circuitry to convert the voltage, dim the LED by cycling it on and off, and maybe change the color, in a lamp, and plug in LED bulbs that don't do much of anything but light up ? The bulbs, being still eventually disposable, shouldn't contain such expensive electronics. The lamp could also have timer and motion sensing functions, if desired. To those who speak British English, by "lamp" I mean "a light fixture, standing on a table or the floor" (what do you call that there ?). StuRat (talk) 14:19, 13 January 2009 (UTC)

I had an early compact fluorescent bulb with a replaceable bulb and the electronics in the base. When it failed, it was the base and not the tube. (Perhaps the ballast?) What are the likely failure modes for an AC powered LED lamp? The actual LED can certainly fail, or lose brightness, but I expect the failure of a capacitor, resistor, diode etc could also put the lamp assembly out of commission. Some redundance could be built in by having multiple lamp drivers as well as the multiple LEDs seen in high brightness LED lights. Power delivered to a lamp is subject to occasional spikes from nearby lightning or from utility switching, and I would expect that the power electronics driving the actual LED are prone to premature failure from these spikes, typically before the LED itself fails from age after those claimed tens of thousands of hours. Some compact fluorescent packaging does warn against use on motion sensors, because each startup reduces the lamps life. It also warns against timers, for unstated reasons. If the timer has a mechanical switch and turns it on and off one or two times a day, I do not see why it would reduce the lifetime compared to using a manual light switch. If solid state switching is done, I can understand how there might be problems, similar to dimmer use. Incandescents do pretty well switched on and off, as in motion sensors, turn signals on cars and those old flashing theater marquees. I think LEDs should not be affected much by multiple switching on and off. Edison (talk) 16:10, 13 January 2009 (UTC)

LEDs are immune to failure from switching on and off -- the most common way of dimming an LED is to cycle it on and off hundreds of times a second, varying the relative lengths of the "on" and "off" parts of the cycle. Assuming you don't overheat it, an LED will fail by fading over the course of 100,000 hours or so. --Carnildo (talk) 23:08, 13 January 2009 (UTC)

so much for your precious physics!

I found a little hole in your physics there. I had put some frozen food into a cold pan and as I turned on the gas I noticed it was already steaming! "It can't possibly be hot yet", I thought, and sure enough, both the pan and the food were QUITE COLD TO THE TOUCH. Aha! I came to the only reasonable conclusion: I had activated physics for very warm, steaming foods by putting SUCH A COLD food into the pan that the value, which wasn't expected to be negative, actually overflowed and activated high positive heat value physics. So much for your precious physics: either hot foods steam or cold foods steam, you can't have it both ways without running into a contradiction.

I came here for advice on where to publish my findings, since the physics community will obviously continue to cling dogmatically to their ridiculous beliefs even in the face of such unambiguous evidence. I was thinking of approaching cooking journals. Any thoughts? Thanks! —Preceding unsigned comment added by 82.124.85.178 (talk) 22:33, 12 January 2009 (UTC)

Darn! You found us out - now we're going to have to teach you the secret handshake and everything!

...unless of course warm air rising out of the hot pan was meeting the cold from the food and condensation was formed in the ascending air column...but no. At this point you either join with us or we push you into the shark tank (and ours DO have lasers on their heads). SteveBaker (talk) 22:50, 12 January 2009 (UTC)

This week I brought an antique cast-iron Dutch oven, which had been outside in zero (Fahrenheit) weather into my kitchen, and I noted steam-like vapor manifesting inside it. Could this be the same phenomenon noted by 82.124.85.178? Edison (talk) 03:01, 13 January 2009 (UTC)

Since no-one's mentioned it, I'll say it's clear that cold fusion is to blame. Algebraist 03:04, 13 January 2009 (UTC)

I agree, cold fusion is the most likely explanation. (Steve could be right about it being condensation: the air inside the oven is cold so when the water vapour in your warm kitchen enters it it condenses into mist, but really, who would believe such an unlikely sequence of events?) --Tango (talk) 03:09, 13 January 2009 (UTC)

It might be the ghost of the steam from the stew my Great-Grandmother made in it in 1909. Edison (talk) 03:29, 13 January 2009 (UTC)

By any chance was that antique cast-iron Dutch oven equipped with integrated circuits? I'm thinking you let the smoke out. --Scray (talk) 04:49, 13 January 2009 (UTC)

The 'letting the smoke out' joke pre-dates integrated circuits and even the transistor. I believe it was first used in the context of the Lucas electrics company that made notoriously bad parts for British cars [11] but it could even pre-date that. SteveBaker (talk) 05:50, 13 January 2009 (UTC)

If you were working in Fahrenheit, maybe the temperature of the freezer was 0°F and then you inadvertently divided by zero and made the temperature not a number! --Anonymous, 04:51 UTC, January 13 + 0°F, 2009.

There was very little integration in my Great-Grandmother's time and locale. Edison (talk) 05:30, 13 January 2009 (UTC)

's OK...anon was talking about division - not integration. I'm sure there was plenty of division back then. :-) SteveBaker (talk) 05:50, 13 January 2009 (UTC)

I just went outside and steam issued from my mouth! I wasn't angry and no fire came out of my nostrils. It must be a manifestation of the same effect. I'll write a paper and put it on ArXiv before you and get all the credit!!! Ha to you!!!! Dmcq (talk) 09:44, 13 January 2009 (UTC)

You fools ! We can harness this phenomenon to create a perpetual motion inter-dimensional portal, use it to contact a benificent alien (but still humanoid) race with advanced technology, and begin an era of peace, prosperity and time travel for all. If only I could find my sonic screwdriver. Gandalf61 (talk) 10:07, 13 January 2009 (UTC)

Don't forget your towel! --Scray (talk) 11:40, 13 January 2009 (UTC)

Perhaps you found Caesar's last breath after all these years? --Sean 13:48, 13 January 2009 (UTC)

I'd give it up. Last week, I was certain that my rock-solid, irrefutable proof for the existence of god would win me a Nobel Prize but it was all for naught. Modern science simply isn't ready for revolutionary theories such as ours. They're too dangerous. They'd upset the established order of the powers that be. I know now how Galileo must have felt. E pur si muove! ;) 216.239.234.196 (talk) 14:17, 13 January 2009 (UTC)

That's what you think. We all submitted detailed papers on this amazing phenomenon as soon as we read the question, all the jokes are just to put other people off the scent! Grab a copy of next month's Nature, it's sure to be there (I don't know who got their paper in first...). --Tango (talk) 15:10, 13 January 2009 (UTC)

But the question on everyone's mind is: Will science ever recognize Time Cube truth as proposed by Dr. Gene Ray, the world's wisest human? A Quest For Knowledge (talk) 15:24, 13 January 2009 (UTC)

In unrelated news: yesterday I made some soup that was too hot, so I blew on it to cool it down. After that I went outside and my hands were cold, so I cupped them and blew on them to warm them up. Sounds impossible, I know, but that's what actually happened. Azi Like a Fox (talk) 22:20, 13 January 2009 (UTC)

That's easy...you had first partitioned yourself (or your breath at least) into hot and cold regions. This process takes energy (going against equilibrium and reducing entropy), which is why you felt the need to eat the soup. When exhaling, there is little to no energy transfer within you and your air (you have already established the thermal imbalance, and are now just pushing the air out, whatever state it is). The temperatures thus re-equilibrate as usual: the cooler air came out when blowing on a relatively hotter object and the hotter air came out when blowing on a relatively cooler object. DMacks (talk) 22:31, 13 January 2009 (UTC)

Readily explained by autonomic control of phlogiston glands in the oropharynx. Any sentence in a RD answer with 3 or more science-related WP links has to be true! --Scray (talk) 04:14, 14 January 2009 (UTC)

Sadly, any RD answer containing one or more alchemy-related WP links is never true! The two effects cancel out and therefore your post is surely about to vanish into a 'poof' of bits, nibbles and bytes. SteveBaker (talk) 15:15, 14 January 2009 (UTC)

Nobody mentioned sublimation (chemistry) yet? There was probably frost on the frozen food. Nimur (talk) 17:10, 15 January 2009 (UTC)

Gravitational Earth xray

I am looking for a magazine article from between 92 - 98 where they x-rayd the Earth using its own gravitational field to do it. In the x-ray there were three large oval shaped objects that they claimed were not made of normal matter. How can I find this article?Creationvger (talk) 23:03, 12 January 2009 (UTC)

I don't know what article you are talking about, but I believe you are describing Physical geodesy. Our article may be of interest. --Tango (talk) 23:25, 12 January 2009 (UTC)