Wikipedia:Reference desk/Archives/Science/2014 February 3

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February 3

How far below the horizon could I see the sun from mount everest?

I've heard the trick of being able to see the sun set twice if you lay down and watch the sun set and then quickly stand up. I also know that due to the earth's refraction we can still see the sun when it is about 1º below the horizon. Now I might be able to figure this out for myself by watching for when the sun's light no longer lights up the tallest of the thunderheads and then looking a smartphone app that shows the current sun elevation, but it's winter here in Florida so no thunderheads to help me out. I looked at the article at horizon but couldn't really wrap my head around which equation would help me out.I think it is basic trigonometry, but my brain is a bit rusty. (the motivation for this question stemmed from wondering about the visibility of partial eclipses at sunrise/sunset when the maximum eclipse is well below the horizon at sea level)  — TimL • talk 08:59, 3 February 2014 (UTC)

You could use an online calculator for calculating the distance to the horizon: [[1]]. I don't believe you need trigonometry for that, the Pythagora's theorem should be enough. OsmanRF34 (talk) 13:34, 3 February 2014 (UTC)

Although the curved hypotenuse (ie, the curvature of the earth) makes it a bit tricky. These calculations were important for battleships in the pre-radar era, as knowing how far away an enemy ship on the horizon was, gave you a clue as to how to aim your guns. Alansplodge (talk) 14:04, 3 February 2014 (UTC)

No, it's not tricky. The hypotenuse is not on the curve. Indeed, there is no curve here. There is a right angle where your view 'touches' the Earth. And you know two sides of these triangle. One of them is the radius of the Earth (one leg of the triangle). The other (the hypotenuse) is the radius of the Earth added to the height your eyes are over the Earth surface. Your are trying to discover the other leg of the triangle. OsmanRF34 (talk) 14:11, 3 February 2014 (UTC)

Quite right. I should know better by now. Alansplodge (talk) 16:11, 4 February 2014 (UTC)

Let's ignore refraction and assume a spherical Earth with radius R. If you are a height h above sea level then the line of sight to the horizon will be at an angle θ below the horizontal where θ is given by:

$\theta =\cos ^{-1}\left({\frac {R}{R+h}}\right)$

If we take R to be 6371 km and h to be 8.8. km (the approximate height of Mount Everest) then θ is about 3 degrees. The sun takes about 12 minutes to traverse an angle of 3 degrees. Of course, if you are really on Mount Everest your local horizon will be domonated by other nearby mountains, so your effective line of sight to the local horizon will probably be rather less than 3 degrees below the horizontal. Gandalf61 (talk) 14:48, 3 February 2014 (UTC)

Yes, the terrain to the east and west of Mount Everest is very high, and you can't even come close to seeing the sea-level horizon in those directions. There are other places where you'd be able to see a lot farther, even if the peaks are not as high. Looie496 (talk) 17:24, 3 February 2014 (UTC)

That raises an interesting question which the OP's question leads to: What is the highest mountain from which an ocean is visible? ←Baseball Bugs ^{What's up, Doc?} carrots→ 17:32, 3 February 2014 (UTC)

Mauna Kea comes to mind. From the top, at an altitude of about 14,000 feet, you can see ocean in all directions - provided the day is clear. Nimur (talk) 21:11, 3 February 2014 (UTC)

That's about half the height of Everest and the other tallest Himalayan peaks, so it would be a good one to test with. First compute what the answer "should be", and test it by one of you going to the mountaintop and one of you going to the shore, and compare notes via cellphone. As an added bonus to that experiment, you're in Hawaii, which is generally a better climate than the Himalaya range. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:16, 3 February 2014 (UTC)

As I recall, you can see the ocean but not the shore, because the south-eastern coast is obscured by Mauna Loa. Nimur (talk) 23:40, 3 February 2014 (UTC)

The question would be whether the team member who's on top of the mountain can see the ocean's horizon. That assumes the team member near the shore also has a clear view of the ocean's horizon. ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:10, 4 February 2014 (UTC)

Mauna Kea is the wrong answer anyway. This page by an experienced climber says that the Pacific Ocean can be seen from Mt. Aconcagua in Argentina. Its height above sea level is about 1.5 times Mauna Kea's. And this page states that it's the highest mountain that can be seen from the sea (which is equivalent to seeing the other way, of course). At 6960 m, the horizon distance using the calculator linked above should be almost 300 km; parts of the coast of Chile are less than 140 km away. So if the view is unobstructed and the air is clear, no problem. --50.100.193.107 (talk) 01:24, 8 February 2014 (UTC)

Is every death by drugs a overdose?

Couldn't it just be some sort of bad reaction, which could happen with any amount of the same drug? Without any trace of a given drug a person wouldn't die of it, so in this sense it's clear that any death by drugs is an overdose. But overdose seems to imply that the quantity was too much, not that an interaction happened. OsmanRF34 (talk) 12:33, 3 February 2014 (UTC)

I'm no expert, but I imagine that you could also be poisoned by something else being mixed in with the drug that you didn't know about, or you could do something fatally dangerous while "under the influence", neither of which could be described as "an overdose". Alansplodge (talk) 14:10, 3 February 2014 (UTC)

Paraquat was one such toxic contaminant, in marijuana. Drug dealers cutting drugs with whatever nasty chemical is at hand is also a problem. During Prohibition in the US, toxic wood alcohol was also a common contaminant in grain alcohol. StuRat (talk) 15:41, 3 February 2014 (UTC)

News reports say they're going to get going on Hoffman's autopsy pronto. That should tell us what specifically killed him. ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:32, 3 February 2014 (UTC)

You can get an embolism if you mix air with your heroin. Technically not the drug, but close enough. No idea how common it is, but pretty sure the actual heroin kills more. InedibleHulk (talk) 16:14, 3 February 2014 (UTC)

• NO, people have allergic reactions to certain drugs which are otherwise taken at a small, therapeutic dose. Surely you've heard commercials warn, "If you develop a sudden rash, notice swelling of the tongue, and have trouble breathing, stop taking fratastatin immediately, and make an appointment with your coroner," μηδείς (talk) 16:23, 3 February 2014 (UTC)

I'm trying to figure out what would be the proper dose of heroin. Although it might be that, by definition, an overdose of anything is "just enough to kill you." Like if you're highly allergic to peanuts, maybe you could survive eating a few - but if you ingest an entire container, you might be in major trouble. ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:29, 3 February 2014 (UTC)

If you are highly allergic to peanuts you are at risk of anaphylaxis from exposure to trace amounts. Sufferers given oral peanut therapy can only tolerate five peanuts a day after six months increasing exposure. Richerman (talk) 22:52, 3 February 2014 (UTC)

For recreational use, the 'proper' dose is presumably the minimum dose which produces the desired physiological and psychological effects.

Heroin is prescribed to addicts in some countries (generally under fairly restrictive, controlled, specific conditions) as part of a harm reduction strategy and/or to ease withdrawl symptoms.

Heroin is used clinically as a potent analgesic. Taken orally, it is deacetylated and enters the system as morphine. As an injectable, in the UK it is used more often than morphine for treatment of acute pain (in clinical use, the choice between heroin and morphine is down to a combination of history, training, government regulations, and differences in pharmacokinetics and bioavailability in certain circumstances). So yes, there are clearly defined 'proper' doses of heroin for a wide variety of situations. TenOfAllTrades(talk) 16:50, 3 February 2014 (UTC)

The articles on drug overdose and adverse drug reaction suggest that indeed bad things other than overdose can occur. "The term 'overdose' is often misused as a descriptor for adverse drug reactions or negative drug interactions due to mixing multiple drugs simultaneously." More links to related subjects in those articles. 88.112.50.121 (talk) 18:47, 3 February 2014 (UTC)

Like a lot of philosophical things in biology, the boundary tends to disappear when you look closely. For example, I suppose taking morphine + codeine would produce a harmful drug interaction ... taking too much opium (containing the two intermingled) would be an overdose. Wnt (talk) 23:15, 6 February 2014 (UTC)

With some drugs, other substances can dangerously amplify their effects. The most commonly cited example of this is that eating grapefruit will increase the body's sensitivity to a wide range of drugs - resulting in the symptoms of an overdose, even for people taking the correct amounts. SteveBaker (talk) 19:13, 3 February 2014 (UTC)

Pre echo removal

How can I remove pre echo from my audio recordings using a sound editing package?--86.184.57.126 (talk) 16:06, 3 February 2014 (UTC)

I don't know of a tool that does it directly.

The most obvious suggestion is to:

1. Look carefully at the audio wave-form that precedes the start of the recording and try to estimate the delay and the relative amplitude of the pre-echo compared to the true sound.
2. Duplicate the track, shift it in time and reduce it in amplitude to match the delay on the echo. The time shift will need to be very accurate to do this well.
3. Subtract the shifted, quieter version of the track from the original.
4. Play with the delay and the amplitude reduction until you're happy with the results.

I think you can do all of those steps in (for example) Audacity - which is a free/OpenSourced program...but I've never tried it.

The likely problem is that some of the mechanisms that cause pre-echo (such as audio tape print-through and groove distortion in vinyl records) may produce somewhat varying delay and amplitude throughout the recording. That might mean that you can correct this problem for short recordings - but not for long ones.

One problem with this is that if there is noise in the recording that happened AFTER the print-through happened, then you'll be adding pre-echoed noise into the recording by doing it.

Another problem with vinyl record pre-echo on stereo recordings is that the echo will not always be on both sides of the stereo image identically - and one side of the original may have echoed more strongly into the other. So cross-talk maybe a major issue here.

SteveBaker (talk) 19:03, 3 February 2014 (UTC)

What about Spectral subtraction ? Would that work?--86.182.50.230 (talk) 16:43, 4 February 2014 (UTC)

How long would it take for a cylinder of ice 2850m high and 2850m in diameter to melt?

First an explanation: This is not a homework assignment! I'm a linguistics major who graduated a long time ago :) I want this question answered for a personal creative writing project. I have attempted to solve this problem on my own but I've reached a brick wall where my knowledge and ability is totally insufficient, and would really appreciate someone who actually knows this stuff to help me out.

The problem is as follows:

The cylinder of ice is 2850m in length and 2850m in diameter. One of its flat surfaces is on rock and it is surrounded by air on all other sides. The ice starts at -45C and the surrounding air temperature is 5C. How long would it take to completely melt?

A back of the envelope calculation is all I really need, just so I can get an idea if it's going to be more in the order of years or centuries. Thanks very much to anyone who can help me with this. --87.82.207.195 (talk) 20:17, 3 February 2014 (UTC)

Whether there's any wind or sunlight on it would make a huge difference, but I think centuries is more what we're talking about. Also notice that even small impurities will tend to concentrate on the outside, after some ice melts, adding a layer of insulation that won't melt away.

The ground temperature under the ice would also play a roll. Of course, unless it had a major source of heat like volcansm or an underground stream, the ground would soon cool down to match the ice's temperature. Also, if the humidity is low, you could get significant sublimation of the ice directly to the air, without melting first.

Something else to consider is that that much ice, over years, will behave more like gelatin than a solid. That is, it will flatten out and flow downhill, just as glaciers do. The flattening out will increase the surface area and thus the melt rate, as will the inevitable fissures which form, and gullies from meltwater. So, if you hope to keep a cylinder of ice that shape for years, it would need to be in space, away from gravity (although it might even deform a bit under it's own gravity).StuRat (talk) 23:11, 3 February 2014 (UTC)

[dumb error fixed: see below] Hmmm, wind speed and rainfall would also play a major role. Anyway, the heat of fusion of water is 79.8 cal/g, the density of ice is something like 0.92 g/cc, and the volume of this thing is 2850 * (2850/2)^2 * pi = 1.82 x 10¹⁰ m^3 = 1.67 x 10¹⁶ g = 1.33 x 10¹⁸ cal = 5.58 x 10¹⁸ J. Now the entire surface of the cylinder is 2850 * (2850 * pi) + (2850/2)^2 * pi * 2 = 3.8 x 10⁷ m^2. So the time x the amount of watts per square meter absorbed has to be equal to the 5.6 exajoules (Yeah, I also looked that one up, but just to check...), i.e. 5.6 E+18 / 3.8 E+7 = 1.46 E+11. Now sunlight is defined as 120 watts/meter or more for a sunshine duration of perhaps 1200-1600 hours per year (3 to 4 hours a day) in some 5 C-ish climates on the map of Europe shown in that article. Though it is sometimes much brighter I've used this as an ad hoc average, but that's still E+9 seconds. (3.16 E+7 is a year). I'm not sure how to qualify the wind and rain heating though, which I'd expect to be more substantial. (The close observer will note that this relation doesn't hold as the cylinder gets smaller; it will go from the present volume per surface to zero. Whether that integrates to a net 1/2 or something else, I haven't tried to figure out. Also note a net 1/2 in the other direction since sunlight won't hit any more than half of it.) This still doesn't bring me to a bottom line on account of the weather variables. Hmmm, wait... suppose the area gets 20 inches of rainfall a year. It comes down at 5 C. It takes 80 C worth of energy to melt ice, so the rainfall would melt 20 * 5/80 = 1.2 inches (5 cm) of ice a year (supposing from the top down) and take, oh, 20* 2850 years to get to the bottom. The wind, well... Wnt (talk) 23:43, 3 February 2014 (UTC)

For the record, sunlight goes up to about 1000 W/m^2, though after accounting for time of day and angle of incidence, having an average flux of 100 to 200 W/m^2 isn't unreasonable. Dragons flight (talk) 06:23, 4 February 2014 (UTC)

@Wnt: I believe you miscalculated by a factor 10³, as the density of ice is about 0.92 x 10⁶ g/m³, while you seem to have used 0.92 x 10⁹ g/m³. Easy mistake to make obviously, but still, it does make a difference. - Lindert (talk) 15:26, 4 February 2014 (UTC)

Crap! I keep rushing back and forth from Wikipedia recently -- too many hasty errors lately. Thanks! Wnt (talk) 16:28, 4 February 2014 (UTC)

It's really hard to say because something that big would have a fairly drastic effect on local weather patterns - and at close to 3km tall - the top of it would be above 'the snow line' - so it wouldn't be melting at all. But there are other more complex effects going on here - the weight of the ice pushing down on the base would increase the pressure tremendously - and that changes the melting point (see Pressure melting point)...The melting point decreases with pressure until it reaches some very high pressure. Then it increases dramatically. I'm not sure if the ice would reach that higher point - but all of this would have a large effect on the melt time. Another point is that the structural stability of the material wouldn't allow it to remain as a cylinder - it would immediately collapse under it's own weight into more of a conical pile - and then flow and spread out like glaciers.

We know that icebergs that are tens of miles across take years to melt - but those have very cold water beneath them and the action of waves tends to break chunks off of them. In 1946, a 140 square mile iceberg was tracked for 17 years...but it would only have been a hundred feet thick or so - a 3km cylinder would be much harder to melt.

My gut feel is that we're talking centuries rather than decades - but certainly many decades. I agree with StuRat that this thing would rapidly turn into a bunch of glaciers flowing away from the original object - but the lifespan of those glaciers depends dramatically on where in the world they are.

From the point of view of writing fiction, I doubt any scientist would argue with you if you said it would take anywhere between 200 and 1000 years...but if you're looking for any kind of realism then forget the idea that it's a cylinder - think "ice-mountain with glaciers".

SteveBaker (talk) 14:23, 4 February 2014 (UTC)

Well, if the Gods who arranged this PR stunt had resort to a perfect thermal conductor (is such a thing possible?) they could have wrapped it every few feet while they were laying it down with cylindrical shells of the stuff, so that over the years its broad sides would display immense messages of deep spiritual significance for the priests among their descendents to spend their lives pondering. ("Buy Moka-Cola") Wnt (talk) 16:34, 4 February 2014 (UTC)

As a minor nitpick but which is also part of an important point, note that it's not totally clear to me top of the ice cylinder will be above the snow line. As our article atests and I guess SB knows, for many places it's well below the snow line. I myself climbed one Mount Kinabalu that's 4km, where frost and ice is not that uncommon but snow very rare [2] (and no I didn't see any snow), at least in modern times. In fact in some such places even frost at 3 km may be comparatively rare [3].

The key point here is the original statement said the surrounding air temperature was 5 degrees C. Where relevant, some of the above answers appear to have assumed that this referred to the average air temperature at or around sea level. If that's the case, then I would guess it's almost definite that 3km would be well above the snow line (which I think is what SB is getting). Even if it's the average air temperature at the median point or alternatively the average average air temperature I would guess 3km would also be above the snow line. On the other hand, if it was 5 degrees C average air temperatures at the top of the cylinder, it seems unlikely the top would be above the snow line, at least initially.

Of course, and the more important point here, I'm presuming as I think did others that 5 degrees C means the average air temperature at whatever point before the cylinder appeared (or assuming the cylinder wasn't there). As SB has said, the appearance of this cylinder will drasticly affect local weather patterns, not said but I guess implied by his and other answers, it's also going to affect local climate. I'm guessing the average air temperatures will be a lower even 10 km away with the appearance of this ice cylinder. So talking about the air temperature after the appearance of the cylinder is fairly confusing.

Nil Einne (talk) 21:49, 4 February 2014 (UTC)

Wow, thanks for all the replies! I hadn't considered a lot of these other issues. Given me a lot to consider. --87.82.207.195 (talk) 18:01, 4 February 2014 (UTC)

If it's for the sake of fiction - could this be a cone rather than a cylinder? A cone with the correct Angle of repose would be relatively stable - and the resulting glaciers would take a while (years, maybe) to form and expand out. A perfectly formed glassy-smooth cone would still be an impressive thing for the aliens/god/bad-guys-from-the-future/mad-scientist to have left behind - and it would remain looking pretty much exactly like that for a very long time. Sadly, I don't know what the right angle of repose would be for solid ice. We know that for snow, it's 38 degrees - but I'd expect it to be much steeper for solid ice. SteveBaker (talk) 14:57, 5 February 2014 (UTC)

I don't think that applies here, as the angle of repose is for solids, while ice of this thickness behaves as a fluid, over long time frames, in the presence of gravity. StuRat (talk) 16:57, 5 February 2014 (UTC)

Assuming the ground stays at -45C and the air at 5C, taking my lead from here and making spherical cow-like assumptions, I calculate the block will reduce in radius/height by about 5 meters in the first year. However, this rate would increase with time because heat gain goes with area but capacity with volume. It's not worth me trying to do the integation! So, I think a few (very few?) centuries might be about right. The heat transfer coefficient, thermal capacity and latent heat of ice come into it but sunshine does not. Shape is not all that important provided length changes during the year are proportionately small. Thincat (talk) 19:07, 5 February 2014 (UTC)

Oh, I should have said, I used a thermal transfer of 12 W/m²K as the reference does but it suggests a possible range of 6 to 30 W/m²K. Thincat (talk) 19:32, 5 February 2014 (UTC)

Yes - I started in on the same kind of calculation - but then abandoned that line of thinking when I realized that the critical factor in the melt rate was the presumed melting point of the ice - which changes with pressure. Since the pressure at the bottom of the object is going to be 2,850 metric tons per square meter (480psi - 2.8 megapascals) - that's just enough to start to have an effect on the melting point...which throws the calculations for a loop because the melting speed depends very sensitively on that melting point temperature. Just as with glaciers, complicated and unexpected things happen when the base of the column of ice melts rather than the surface as you might expect. But the center of the column of ice starts out pretty cold (per the OP's original statement) - which would act to keep it solid. But if the cylinder collapses into a cone - and then starts to flatten out as a fluid (as StuRat explains) - then the pressure at the edges of the (now conical) block reduces and that melt-water will re-freeze as it's squeezed out from below. This makes for an extremely complicated situation - and I'm not at all happy with doing simple math to estimate what happens. When quite experienced scientists did that for the rate of glacier melting with global warming, they got it horribly wrong for all sorts of complicated reasons - and glaciers started to vanish at a rate vastly higher than was initially predicted. I doubt we could come up with math to get the result closer than maybe one order of magnitude to the actual value. SteveBaker (talk) 14:04, 6 February 2014 (UTC)

Hmmm - from a fictional perspective, this offers some interesting possibilities. If the pressure in the center of the block melts the ice - but the edges remain solid - then you'd have melt-water migrating out of the block through cracks - and perhaps producing spectacular ice-geysers and jets of water suddenly squirting out at lethal speeds. With the water being super-cooled at this point, it would re-freeze as it fell - so you might have something like a water jet cutter or even a CryoJet which can happily make holes in half inch thick metal. I bet someone with a taste for action-adventure literature could have a lot of fun killing off minor characters that way! SteveBaker (talk) 14:23, 6 February 2014 (UTC)

How dangerous is Everclear?

Is there anything specific about Everclear, other than its strength that would make it extremely dangerous to do straight shots, or chug it freely from the bottle? I realize that the strength is more than twice that of a typical vodka, so you're going to get drunk quicker (twice as fast - is it even a linear thing?) - but aside from that, is there anything else that justifies the 'Everclear will kill you' belief that seems to be around.

The purpose of this question is not so that I may plan my own debauched drinking session. I don't think that you can even buy it, or anything comparable in my country (that I've seen). I've seen people talking about it (slightly fearfully) online, and joking about the crazy guys who shoot Everclear, is all. --Kurt Shaped Box (talk) 21:04, 3 February 2014 (UTC)

No. Alcohol is alcohol. The real danger is people not realizing the strength and drinking too much, too fast. Oftentimes people associate everclear with backyard distilling operations, in which case, contaminants like methanol, etc. can find their way into the everclear. But for the legally produced and regulated everclear, there is no danger. Justin15w (talk) 21:10, 3 February 2014 (UTC)

"Alcohol is alcohol" is not quite correct. Everclear is a very strong but consumable form of Ethanol a.k.a. grain alcohol. Wood alcohol, or Methanol, can be deadly. Of course, even consumable alcohol can be poisonous if too much is ingested. Everclear is typical added to something else, to "spike" it. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:14, 3 February 2014 (UTC)

It is my understanding, though I don't have a ref, that if you concentrate ethanol to nearly 100% (absolute alcohol), it actually is more dangerous than the same amount of total ethanol consumed as a larger volume of more dilute liquor. The reason is that, at such high concentrations, it sucks water out of your tissues on its way down, which can severely irritate your throat and esophagus. Whether EverClear is that concentrated, I don't really know.

By the way, there is another danger to lab-grade ethanol even if you dilute it, which is that, in order to get ethanol more concentrated than the ethanol–water azeotrope, it is distilled using benzene, which causes cancer. How much benzene is left, or how dangerous that is, again, I don't really know. But just because the bottle has a liquor tax stamp (in the US at least) doesn't necessarily mean it's safe to spike the punch with it. --Trovatore (talk) 21:23, 3 February 2014 (UTC)

In chemistry lessons at school, they always told us not to even think of drinking the lab ethanol - because it would kill you. I was never sure whether they actually meant it, or it was just something that they said to discourage 14 year olds from stealing it and getting drunk. Later on in life I met someone who worked in a lab, who told me that the stuff goes great with orange juice, so I dunno... --Kurt Shaped Box (talk) 21:36, 3 February 2014 (UTC)

Well, they may both have been right. If the issue is cancer, then it very well might kill you, but not so fast as to keep you from coming to the conclusion that it goes great with OJ. --Trovatore (talk) 21:48, 3 February 2014 (UTC)

School Chemistry Lab alcohol will be Denatured alcohol in most cases. APL (talk) 23:05, 3 February 2014 (UTC)

• Everclear is meant for consumption, so you don't need to worry about contaminants. But it is a wicked desiccant, as Trovatore mentions, and can lead to acute and chronic damage, along the path of Christopher Hitchens. If you leave Everclear open to the air it will absorb water until it reaches a certain weaker proof at equilibrium with the ambient humidity. Lab alcohol is often denatured alcohol, meaning it has been adulterated to make it unpalatable, and thus not subject to the steep tariff on drinking alcohol. But not all lab alcohol is adulterated, since some reaction need pure ethanol. Basically, Everclear is a vanity item. μηδείς (talk) 22:05, 3 February 2014 (UTC)

Note that there is another reason why drinking concentrated alcohol is more dangerous than drinking the same quantity of alcohol, mixed with more filler (mainly water). That is because the filler limits your rate of consumption. If it takes a gallon of beer to reach a fatal level of alcohol poisoning, most people will find it difficult to drink a gallon quickly. They might very well be able to drink a gallon of beer over the course of a night, but their body is metabolizing the alcohol during that period, so it never reaches a fatal level. Also, since the alcohol level builds up more slowly, they are likely to pass out or vomit before they reach a fatal blood alcohol level.

Now, with highly concentrated alcohol, provided they can choke it down, it's relatively easy to receive a fatal dosage quickly. StuRat (talk) 23:05, 3 February 2014 (UTC)

What, in ounces, would be a fatal LD50 of Everclear? μηδείς (talk) 01:11, 4 February 2014 (UTC)

It would, of course, be unethical to kill half your human test subjects to determine the LD50. However, the LD50 for rats, fed a 70% ethanol solution orally, is >90 mL/kg of body weight, according to [4]. From there you can convert from metric and adjust for the percentage of ethanol in Everclear (there are apparently 2 concentrations commonly sold). StuRat (talk) 01:27, 4 February 2014 (UTC)

And of course you have to be careful with applying this LD50 to humans, because rats and humans differ, sometimes dramatically, in what is toxic and why (e.g. [[5]]). Another example: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2259215/ Why isn't this wikilink to Median lethal dose showing up correctly? --TheMaster17 (talk) 10:28, 4 February 2014 (UTC)

This might be an urban legend, but I have heard stories of people drinking neat Polish vodka of similar strength, and having no immediate effect, supposedly "because osmosis means that water comes in to your stomach first to dilute it". After 10 to 15 minutes they have suddenly become very drunk and in some tellings fallen unconscious and been rushed to hospital. I have no desire to test this experimentally. -- Q Chris (talk) 11:54, 4 February 2014 (UTC)

Left as an exercise for the reader, of course, is the question of how long it takes for beverage alcohol of any sort, once ingested, to make its way from the gastrointestinal tract into the bloodstream. Most absorption of ethanol happens in the small intestine, though a bit is absorbed through the stomach lining as well. In a fasting state – that is, with an empty stomach – beverage alcohol will pass fairly quickly through the stomach into the small intestine, but even then there is a lag of several minutes between beverage consumption and a significant rise in blood alcohol levels. (You can see some real kinetic data in this study, which also shows that patients who have undergone gastric bypass surgery have a much shorter lag between ingestion and absorption of ethanol.) On a full stomach, the kinetics will be even slower. No need to resort to 'osmosis' for an explanation. TenOfAllTrades(talk) 15:14, 4 February 2014 (UTC)

Is it true that a person can become a stutterer by wilful practice?

Is it true that a person can become a stutterer by wilful practice, or is the speech disorder neurological? (Please note: this question is not to demean stutterers in any way, as I have high respect for these people. I am only asking out of curiosity.) 140.254.227.177 (talk) 21:21, 3 February 2014 (UTC)

Two words: Mel Blanc. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:15, 3 February 2014 (UTC)

Thufferin' thuccotash! Practice can also help fake various mental disorders. InedibleHulk (talk) 11:25, 4 February 2014 (UTC)

On that note, hats off to Clarence Nash for creating one of craziest, unintelligible characters this side of Taz. InedibleHulk (talk) 11:32, 4 February 2014 (UTC)

Yes. Hence the Mad character "Darnold Duck", whose quacking had to be translated. I'm just wondering if the OP meant that someone could literally develop an uncontrollable stutter. The orginal voice of Porky Pig was a guy who was a real-life stutterer but couldn't control it. Blanc's voice for Porky was totally under his control, i.e. he could turn it on and off as needed. Obviously, Colin Firth did a fake stutter very well in The King's Speech. ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:52, 4 February 2014 (UTC)

Yes, that's exactly what I meant. An uncontrollable stutter developed by wilful practice of a non-stutterer. 140.254.227.61 (talk) 14:27, 6 February 2014 (UTC)

joule heating is rii but also vv/r

so.. why using high voltage to distribute power? thanx --80.182.18.25 (talk) 22:13, 3 February 2014 (UTC)--80.182.18.25 (talk) 22:13, 3 February 2014 (UTC)

In the formulas P = I²R and P = V²/R, the value of R is the total resistance in the circuit, including both the resistance of the wires, and the resistance of the load. When one is only interested in finding the power dissipation in the wires, the formulas do not apply. Jc3s5h (talk) 23:05, 3 February 2014 (UTC)

They do apply if you use the right values, where P is the power lost in transmission, R is the resistance of the transmission line, I is the current, and V is the voltage drop only along the transmission lines, not the total voltage. 80...125 was probably confused by thinking of using the total voltage dropped across both the transmission lines and the load in their calculation for power lost. -- ToE 01:25, 4 February 2014 (UTC)

Indeed it's awkward that P = V²/R implies that the higher is V the higher is P --Ulisse0 (talk) 17:45, 4 February 2014 (UTC)

Yes, I should have noted that, in these type of problems, it is typically the power consumption of the load, not its resistance, which is held constant when considering different transmission line voltages. With twice the transmission voltage, a transformer with twice the step-down ratio will be used so that the load will still receive its rated voltage. From the load's point of view, it still receives the same voltage and draws the same current. The step-down transformer, however, receives an input of twice the voltage and draws half the current compared to the lower transmission line voltage scenario. With half the current, the I²R transmission losses are clearly halved. While that is the easiest way of looking at it, V²/R can be used as well by computing the proper V -- the voltage dropped along the transmission lines. With half the current, this voltage drop will be halved, so V²/R is similarly quartered. I²R is the more straight forward computation, but it is reassuring to see that it does not contradict V²/R as first appears.

Relevant links are Ampacity, Voltage drop, and Overhead power line#Conductors, which states: An optimization rule called Kelvin's Law states that the optimum size of conductor for a line is found when the cost of the energy wasted in the conductor is equal to the annual interest paid on that portion of the line construction cost due to the size of the conductors. (HTH. Keit would have done better.) -- ToE 22:44, 9 February 2014 (UTC)