Wikipedia:Reference desk/Archives/Science/2007 August 22

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[edit] August 22

[edit] Medicine - The Spleen

Why does it appear that males are more suseptable to accidental damage to the spleen than females? Wally3178 —Preceding unsigned comment added by Wally3178 (talk • contribs)

What makes it appear that way? Mrdeath5493 03:21, 22 August 2007 (UTC)
I would take a guess that male humans are more likely to have accidents than females, as they do more risky things. There are more likely to drive fast, try extreme sports or want to take on that dare for a thrill. Graeme Bartlett 04:02, 22 August 2007 (UTC)
(edit conflict stole my sarcastic thunder) Spleen injuries tend to be impact related. Men tend to do more stupid physical stuff. I hope that is technical enough for you. Plasticup T/C 04:04, 22 August 2007 (UTC)
Also, men are probably more likely to falsely claim spleen trauma, which I imagine is what prompted the original question. -- BenRG 11:43, 22 August 2007 (UTC)
Really? I have never heard of anyone pretending to hurt their spleen. It seems like a rather wimpy organ to pick. If you are going to lie, go for something exciting like a liver or a kidney. Plasticup T/C 16:41, 22 August 2007 (UTC)

[edit] is this right?

I'm thinking BS on this one. What could the speed at which you lower objects into it matter at all? In all cases, (I believe) you can lower it in and there's no additional tautness on the rope as you lower it even if it goes all the way down to singularity, but you're completely unable to budge it a nanometer outward.. and the effect is exactly the same whether you're moving it fast or slow. This section seems to be implying that if you go slow enough, you'll never even reach the event horizon and so no matter how much rope you play out you can always pull the guy back in. Is there any basis for this theory? --frotht 00:26, 22 August 2007 (UTC)

You're right, the article is wrong. The event horizon is a finite distance away, and if you extend more than that much rope, it will go through. You'll never see it go through, because the light can't escape either.
You can't lower an object gradually all the way to the singularity, though, because once you're inside the event horizon there's no such thing as a stationary (dangling) state. Your rope will break -- it's a physical impossibility for it not to. -- BenRG 00:43, 22 August 2007 (UTC)
You can slow it down though, and if you have a really strong (and stretchy) rope shouldn't you be able to hold on long enough for it to reach the center and 'dangle' (hang there moving very slowly downward) for a bit? --frotht 01:42, 22 August 2007 (UTC)
I just watched a documentary on super-massive black holes. It mentioned that many scientists believe the event horizon around them is fundamentally different than a regular black hole's event horizon. You can pass through the event horizon (which means a rope could pass through). Once through, the incoming matter will collide with matter trying to escape the singularity - turning it all into a scorching mess of exploding particles. So, there's no possibility of the rope reaching the singularity - but it could get past the event horizon. Of course - the documentary could have been a bunch of bull. At least I didn't see Michael Moore in the credits anywhere. -- Kainaw(what?) 02:47, 22 August 2007 (UTC)
I'd call BS on that as well, at least working under a purely GR system (quantum relativity may prove me wrong). The only significant difference between a supermassive black hole and a normal black hole (of a couple of solar masses, say) is that tidal effects near the event horizon are negligible, so you won't be "spaghettified" when you pass through it. And it's not like the event horizon is a magical wall that lets you in and doesn't let you out again, it's the boundary where all time-like and null curves (i.e. those travelled by massive particles and photons, respectively) point inwards, so there's no way you'd run into particles "trying to escape the singularity" - at best you could accelerate yourself into the path of slower-moving particles but I don't think it would be much worse than running into them out in normal space.
I'm pretty sure froth is right - the rope going through the event horizon would pull on you, stretching further and further, until either (a) it breaks just outside the horizon, or (b) it pulls you in with it. Confusing Manifestation 06:56, 22 August 2007 (UTC)
In a Kerr black hole there are two event horizons, and the inner one is also a surface of infinite blueshift -- as you approach it you see the entire future of the outside world compressed into a finite time. This would certainly fry you, and may be what the documentary was talking about. Also, if you got past that, the singularity is timelike, so you might indeed run into something emitted from it. But I doubt very much that the interior portion of the Kerr solution has physical significance, and if it does then it applies equally to black holes of all sizes.
What you said after "I'm pretty sure froth is right" is right, but I'm not sure it's what froth said. Given an arbitrarily strong rope you can dangle things arbitrarily close to the event horizon, but not arbitrarily close to the singularity. (edit: Well, not from outside the hole. Once you've passed through both event horizons, I don't think there's anything in general relativity that prevents you from toasting marshmallows on the singularity.) -- BenRG 11:54, 22 August 2007 (UTC)
So what's keeping the rope from passing the event horizon? Sure you never see it pass the event horizon (what would this even look like from the ship's point of view? would the rope just get longer and longer out into the vanishing point of the 3d perspective?) but from the end of the rope's point of view it's gettin fried by apocalyptic energies inside the black hole --frotht 02:11, 23 August 2007 (UTC)
Nothing keeps it from passing the event horizon, but there's no way to transmit tension from outside the horizon to inside. Inside the event horizon there's no such thing as a stationary (suspended) state -- the light cones point inward, and "staying in the same place" would require superluminal motion. In the Kerr solution, you can suspend an object above the singularity by a rope attached to a rocket that's inside both horizons, but not by a rope that crosses one or both horizons. -- BenRG 17:26, 23 August 2007 (UTC)
Whoa whoa whoa, you mean to say that the rope could actually pull you in with it? What if due to an extraordinarily powerful engine on your rocket ship you were hovering just above the event horizon and dangling a rope down and holding it so that it falls very slowly, and somebody down inside the event horizon tugs on the rope intermittently, sending a morse code message if you're measuring the pull on the rope? Seems impossible, yet inevitable if the rope can "pull you in" --frotht 02:08, 23 August 2007 (UTC)
If you lower part of the rope past the event horizon, the rope must either break or fall through in one piece. If it falls through in one piece, and you don't let go, then by definition you fall in too. That's all ConMan meant by "pulls you in". -- BenRG 17:26, 23 August 2007 (UTC)
Could one (in theory) orbit the singularity indefinitely while inside the event horizon, just as you can orbit it outside the EH? --Sean 13:37, 22 August 2007 (UTC)
No, inside the event horizon all the timelines move towards the singularity, so no orbits are stable. Even outside the event horizon there is a zone where no orbits are stable and you would fall in if you did not have that rope holding you up! Graeme Bartlett 22:13, 22 August 2007 (UTC)

[edit] Power used by a car

Hello,

I am trying to determine the average power used by a car in joules or watts. I know it varies from car to car and from terrain to terrain but I am trying to get an idea.

Thanks, Bryan

The power produced by the engine (in kiloWatts) is frequently stated for European cars - but in any case, simply multiply the horsepower number by 0.746 to get kiloWatts. However, that's the peak output of the engine - most of the time it's going to be a lot less. Also, if you are interested in the energy USED by the car, a typical internal combustion engine is only 20% to 30% efficient. So, take my car (a 'tricked out' 215hp MINI Cooper'S) - 215hp is 160kW when it's redlined - but at 20% efficiency, we're consuming the equivelent of 800kW of energy from the gasoline. But most of the time, the engine isn't running at full power, so 80kW at the output of the engine (and 400kW of fuel consumed) would be about right for my car. SteveBaker 01:07, 22 August 2007 (UTC)
Spelling note: it's "kW" with capital W, but "kilowatts" with no capital. All metric units named after people work that way.
The 160 kW is right, and 20% efficiency is plausible, but I don't believe the last set of numbers. The problem can be seen by looking at the other part of the question and speaking of joules, which measure energy, not power. According to Wikipedia at gasoline#Energy content, one liter of gasoline produces about 34.6 megajoules (34,600,000 joules) of energy. (Checking other random sources on the web I see somewhat different numbers, but that's in the right ballpark, anyway.) So for Steve's car to be burning fuel at a rate that produces 400 kW of energy, it must be consuming 1 L every 34,600/400 = 86.5 seconds. That's 11 US gallons in an hour. You wouldn't get far on a tank of gas at that rate.
I think a car in a steady cruising state is actually running at much less than half of its full power. If someone can find figures for the air and frictional resistance of a car at highway speeds it might be interesting to look at the energy consumption that way. But if we assume that the cruising state is actually at 1/8 power and Steve's other numbers are right, then it takes 4 hours to burn 11 US gallons, during which you might drive 240 miles, giving about 22 miles per gallon, which is in the right ballpark at least. So I suggest Steve's final set of numbers are too large by a factor of something like 4.
--Anonymous, August 21, 2007, 03:26 (UTC).
Hmmm - good point about joules vs watts - of course you're right. As to the numbers being too large...well, for my car, horsepower is about proportional to RPM. 160kW is at 7000 rpm - redline. In 6th gear at 70mph, I'm turning about 3500 rpm. So roughly 80kW ought to be what the engine is putting out. Possibly the 20% efficiency number is wrong - I got it from internal combustion engine, but if I'm off by a factor of 4 then the car would have to be 80% efficient and that's not possible for any heat engine. I'll go away an look at the numbers more carefully tomorrow - I need sleep! SteveBaker 05:04, 22 August 2007 (UTC)
<offtopic> A computer programmer...sleeping? Steven, for shame...Someguy1221 05:11, 22 August 2007 (UTC)<offtopic>
Technically, I said I needed sleep - not that I was actually going to get any! :-( SteveBaker 15:35, 22 August 2007 (UTC)
Well, the mistake here is to assume that half the engine speed means half the power. If you're driving up a hill (on a straight road, and not one steep enough to downshift), you'll step on the gas and maintain the same speed at a higher power level. Conversely, go down a hill and you may be doing the same 3500 rpm at 70 mph with your foot off the gas pedal. This shows that engine speed does not depend on power alone. Your car may develop 160 kW of power at 5000 rpm under some conditions (gear and gradient), but under other conditions you could hit the red line before it ever got to 160 kW. Heck, that's why there is a red line: because the engine is capable of developing enough power to go above 7000 rpm and maybe destroy itself. --Anonymous, August 21, 05:30 (UTC).

[edit] Toads and warts

Can a human really catch warts from handling a toad? --Kurt Shaped Box 01:36, 22 August 2007 (UTC)

These sites say no. The second says that "[a] possible source of this myth are the poison glands located on the backs of some species of toad. People who develop an allergic reaction to the secretions from these glands may get bumps that look like warts." — Matt Eason (Talk • Contribs) 03:17, 22 August 2007 (UTC)
Thanks. I thought that it was an old wives' tale - but it seems to be very deep-rooted. I remember being on a school field trip as a teen and hearing another kid being shouted at for picking up a toad. The (science) teacher was like "OMG! Put it down now! You don't have any cracks in your hands do you? Go wash them now! Don't touch your face! You'll get warts!". I know otherwise sane and rational people who just have to 'greet/salute the lone magpie' too. --Kurt Shaped Box 08:19, 22 August 2007 (UTC)
Aw, but you gotta admit — terrifying children sure is fun! --24.147.86.187 13:08, 22 August 2007 (UTC)

[edit] insuline

to maintain the sugar balance of one of my patient i would like to suggest dose of human mixtard insuline of concentration 50:50 as 20 units before breakfast and dose of human mixtard insuline of concentration 30:70 as 8 units before dinner............... so my Q. is whether using this type of combintions at same time is advisable or not? and r there any drawback of of this type of treatment? please help me..... —Preceding unsigned comment added by 59.95.16.110 (talk • contribs)

Please read the medical disclaimer. We cannot give medical advice. — Matt Eason (Talk • Contribs) 03:05, 22 August 2007 (UTC)
I seriously doubt you are treating a patient. If you are, you might consider going back to medical school.
Mrdeath5493 03:19, 22 August 2007 (UTC)
And ask the patient to wait till he completes his medical course ? ;-) -- WikiCheng | Talk 05:03, 22 August 2007 (UTC)
Per WP:BITE and {WP:NPA it is sufficient to cite the medical disclaimer, without the need to attack and insult the questioner. Those new to Wikiedia may not be familiar with the "no medical advice policy." Thanks. Edison 14:36, 22 August 2007 (UTC)

[edit] PHYSICS D/L

I am unable to download the artiicle on 'Physics': the main page is opened , pictures etc uploaded and then the phrase '1 item missing ' appears, which prevents d/l at my end! Clear the glitch if you may. ……Autistic49 04:20, 22 August 2007 (UTC)

If you mean Wikipedia, then the article works fine for me. What's your browser? Splintercellguy 04:42, 22 August 2007 (UTC)
Physics seems to be working here as well. Maybe you have a proxy server problem, if not a browser problem. Nimur 05:49, 22 August 2007 (UTC)
*Jumps on the spot*. Yup, working here too. Capuchin 09:16, 22 August 2007 (UTC)
I dunno - I think my string theory might be broken. :-) SteveBaker 15:32, 22 August 2007 (UTC)

[edit] BOTANY

Smallest chromosome number in angiosperms 2 is seen in which plant 123.108.203.82 9:48 UTC did not sign the question.

Welcome to the Wikipedia Reference Desk. Your question appears to be a homework question. I apologize if this is a misevaluation, but it is our policy here to not do people's homework for them, but to merely aid them in doing it themselves. Letting someone else do your homework does not help you learn how to solve such problems. Please attempt to solve the problem yourself first. If you need help with a specific part of your homework, feel free to tell us where you are stuck and ask for help. If you need help grasping the concept of a problem, by all means let us know. Thank you. --Sean 14:10, 22 August 2007 (UTC)

[edit] sea

why water in seas flows towards bank? are waves occur bec of collision between coming water towards bank and returning water from bank? —Preceding unsigned comment added by Prasanth prav (talk • contribs)

The reason waves come towards the shore is that they are produced in the ocean and not by the land. So waves will always be travelling towards the coast when you are at the coast. There is a secondary diffration effect where waves approaching a coast with a shelving floor will be turned around to approach more perpendicularly. Graeme Bartlett 09:54, 22 August 2007 (UTC)
I don't buy your first answer (think about a large circular island in an infinite ocean). The diffraction answer is the correct one. Water waves slow down in shallower water (especially when the depth of the water is less than about one and a half wave lengths). So if you imagine a gently shelving beach and a wave approaching it from far out at sea at 45 degrees - the part of the wave that hits the shallower water first slows down and the part that's still over deep water doesn't. So the deep water part quickly catches up with the shallow water part until they are both moving over the ocean bottom at the same depth. This makes the wave turn inwards so it's coming in parallel to the beach because that's the only way that the entire length of the wave can be travelling at the same speed. You can see this most clearly in a curved bay where a wave entering the bay bends outwards to precisely follow the line of the beach. In cases where there is no gently sloping bottom (eg where a cliff-face drops straight down into deep water), the waves crash against it at any angle they happen to be moving at. In the case of that large circular island in an infinite ocean - the waves will come ashore all around the island - including on the side where the waves are generally moving away from it! SteveBaker 15:30, 22 August 2007 (UTC)
May be the question and answer are not clear enough. In the case of the circular island in the large ocean, the island will block waves coming from the other side of the island, so on the eastern shore, there will be no waves coming from the west (or north west or south west). Graeme Bartlett 23:43, 22 August 2007 (UTC)
That's not true though - the refraction effect will wrap waves around to the back of the island. You'd expect maybe dead calm water? Nope - you still get waves. SteveBaker 00:52, 23 August 2007 (UTC)
On the OP's question, note that waves do not involve the "flow" of water. Waves move, but the water does not move with the wave (not much anyway). See Ocean surface wave and Ocean current. Pfly 04:01, 23 August 2007 (UTC)
Right. If you put a neutral-bouyancy object into the ocean, it moves with the water in a vertically circular motion. As the depth of the water starts to get close to the diameter of that circle, the circle is forced to squash down into an ellipse - until right at the edge of the beach, the water is moving horizontally up and down the beach. The act of squashing that circle down into an ellipse extracts energy from the wave and therefore slows it down. Which is the cause of the diffraction effect described earlier. SteveBaker 22:43, 25 August 2007 (UTC)
Waves carry energy. That energy is provided by winds and other forces in the open water, and is dissipated as friction at the shore. Therefore waves travel towards the shore. For waves to travel away from the shore, something would have to exert energy to move water up and down at the shore. --Spoon! 02:23, 25 August 2007 (UTC)
That's bogus. Suppose there was a planet that was all ocean with no islands - what would happen with the waves then? What you are describing is akin to arguing that sound waves get sucked into your ears! SteveBaker 22:43, 25 August 2007 (UTC)

[edit] Death by Fire

I have heard that when people die in a house fire, it is typically from smoke inhalation (that is, they can't breathe) and not from the burns / flames of the fire per se. However, if the human body is set afire / burned, what would be the specific biological reason / cause of death? What exactly would you die from? In other words, would it be organ failure, heart attack, shock, ... what does the fire do to the body that causes the death? Thanks. (Joseph A. Spadaro 08:49, 22 August 2007 (UTC))

Burns victums can have massive fluid loss, and after a while major infections. The heart would probably stop when there was not enough blood. Graeme Bartlett 10:04, 22 August 2007 (UTC)
Pertaining to death while burning, there is also suffocation. Attempting to breath flames will damage the throat and lungs to the point that the person cannot continue to breath. This may be considered organ failure of the lungs. -- Kainaw(what?) 11:02, 22 August 2007 (UTC)
Not to mention the effects on the brain.. I'm not exactly sure how this works, but think of how delirious you get when you have a 10 degree (F) fever.. imagine a 1000+ degree fever. --frotht 02:05, 23 August 2007 (UTC)
This is a bit of a circular argument. In the contemporary definition of death there really is only one answer to any question that ends with "what would be the specific biological reason / cause of death?" And that is "cessation of electrical activity in the brain" which is caused by lack of oxygen. No matter if you fell from a great height, had cancer, a heart attack or were burned alive, ultimately you die because your brain doesn't get enough oxygen. Vespine 06:38, 23 August 2007 (UTC)
That's not true for situations in which your brain is destroyed (if what's left is spread out and open to the air, it could very well have plenty of oxygen). Someguy1221 06:52, 23 August 2007 (UTC)
But your brain does not have the capacity to process oxygen out of air, only your lungs can do that, your brain can only get oxygen out of blood. What you are saying is like saying you couldn't die of thirst stuck on a boat in the middle of the ocean since you are surrounded by water, when in fact, that's probably the 1st thing you'd die of. Vespine 00:50, 27 August 2007 (UTC)

[edit] physics

what is the use of neutral wire in a circuit?

Neutral wire. Just because it's called neutral doesn't mean it actually does nothing. The Neutral and Live wires are both "live", they form the circuit. Capuchin 09:55, 22 August 2007 (UTC)
Electric current flows in a circuit, rather than just one way down a wire. This means that current flowing from a wire from a power point has to return someway. The desirable way is for the current to return in a neutral wire. The neutral wire will have a voltage near earth potential much lower than the active wire. However don't rely on this as a power point may have wires reversed by accident. In a three phase system if the currents are not balanced in the three phases, some current will return on the neutral wire. Graeme Bartlett 10:00, 22 August 2007 (UTC)
When electricity flows one way on one wire for a while and then stops we call it "static electricity." Current electricity requires a return path, which is the neutral. Household wiring normally has a "phase" wire which is at the highest potential from ground, a "neutral" which is connected somewhere near the main circuit panel to a ground, and a "ground" or "earthed" conductor, which is present for safety, to provide a return path to ground in the event there is a circuit fault, such as a frayed wiring on the phase conductor allowing it to touch the grounded outer metal shell of an appliance. Edison 14:24, 22 August 2007 (UTC)

"Neutral" means neutral with respect to ground. Properly designed, there is never a potential between the neutral wire and the person. SInce people are often connected to ground, the neutral wire is normally grounded. It is code to ground the neutral wire at point of entrance in residential and most commercial locations to ensure that it is neutral with respect to ground. In a standard 120/240 single-phase entrance, the neutral is the center tap of the transformer. In 120/208 three-phase system, the neutral is the center of the wye transformer. In 120/240, three-phase systems the neutral is the center tap of one coil of a delta transformer. In all cases, the neutral is grounded to ensure that it is neutral to people. --Tbeatty 06:47, 23 August 2007 (UTC)

[edit] Conjoined Twins

Referring to my earlier question, has there ever been a case known or documented that there were three or more twins conjoined? If that is not possible, please explain why. I am trying to sound smart to my little nephew..... thanks! --WonderFran 12:18, 22 August 2007 (UTC)

A web search for "conjoined triplets"[1] suggests there have been several cases of conjoined triplets and quadruplets.--Shantavira|feed me 13:56, 22 August 2007 (UTC)
If you want to sound really smart, I'd respectfully suggest you drop expressions such as "three or more twins". That might tend to confuse a lot of little 'uns. -- JackofOz 02:21, 23 August 2007 (UTC)
THREE twins!? That would be six conjoined kids! --24.249.108.133 03:10, 23 August 2007 (UTC)
Maybe he/she means three sets of conjoined twins? :-P Nil Einne 01:27, 24 August 2007 (UTC)

[edit] How many islands are there?

This question could be split in two, oceanic or inland, I am interested initially in oceanic islands but the other would be interesting too.

For anyone interested in the geography of islands, the following link is amusing, and is what set me off on this train of thought: http://www.elbruz.org/islands/Islands%20and%20Lakes.htm

— PhilHibbs | talk 14:13, 22 August 2007 (UTC)

I think this is another unanswerable question along the lines of Coastline of the United Kingdom - you might start off by counting the islands you can see at the scale of a 1" to 100 miles map - then discover that if you got a 1" to 10 miles map, you'd see a lot of smaller islands that you missed before. When you ran out of high-precision maps, you'd go and visit one of the islands - only to discover some very tiny islands - just a few feet across - scattered around it. Closer up, you'd find large rocks protruding from the ocean and have to conclude that those too have to be counted as islands. Where do you stop? Individual grains of sand on the beach are technically islands in that they are bits of land surrounded by water. The answer is 'fractal' - and in just the way that you can't come up with any kind of a number for the length of a coastline, I'd argue that you can't ever count the number of islands. SteveBaker 15:19, 22 August 2007 (UTC)
Still, you might like to start counting them with the help of our list of islands.--Shantavira|feed me 18:10, 22 August 2007 (UTC)
As with the coastline question, there is no problem with getting an exact number from any of several sources - the problem is that it's doomed never to be "correct". Perhaps if a minimum size of island were specified? SteveBaker 18:22, 22 August 2007 (UTC)
The tinier bits of this volcanic archipelago near Iceland form and erode on time-scales of a few days.
The tinier bits of this volcanic archipelago near Iceland form and erode on time-scales of a few days.
There's also a fallacy in assuming that islands are permanent. How many islands are there at any given instant? This is not even a question of geologic time; Jolnir and Surtsey are examples of large island formation (and total erosion) in the time scale of weeks. Nimur 18:32, 22 August 2007 (UTC)

[edit] Light Bulb Pressure

What kind of pressure is the low pressure inert gas in a standard tungsten filament bulb? Light bulb doesnt give a ballpark figure. Capuchin 15:21, 22 August 2007 (UTC)

I have always assumed it was roughly atmospheric pressure (since nothing dramatic happens if you break an ordinary incandescent lightbulb: you get neither a noticeable explosion nor implosion), but I have no data at hand to back that up. The point of the gas is to partially offset the vapor pressure of the tungsten that would otherwise boil off the filament owing to the very high heat of the filament. I've always (further) assumed that "low pressure" was just a comparative with other lamp types such as quartz-halogen lamps. In QH lamps, the filling gas is at a fairly high pressure and these lamps have been known to explode, especially upon failure of the filament (when the brief arc can overheat the filling gas)..
Atlant 16:33, 22 August 2007 (UTC)
according to these lecture notes [2], it's 0.01 - 0.1 torr. That would be for a light bulb that's actually evacuated (as used to be the usual case). Apparently, though, many light bulbs are now filled with argon and nitrogen at somewhere below atmospheric pressure; in that case the pressure probably changes a lot with temperature. --Reuben 16:45, 22 August 2007 (UTC)
The first practical light bulbs in the 1870's 1880's, with a carbon filament, had to have the vacuum pumped down to an excruciatingly hard vacuum, because any residual oxygen caused early burnout, and because the convection currents of an inert gas also buffeted the fragile filament and caused early failure, as well as cooling the filament and lowering light output. Today only small tungsten filament bulbs have a vacuum, and those over 20 watts or so have an inert gas fill. I have tried carefully venting such a modern 60 watt bulb under water to collect the internal gas and found that it is roughly 3/4 of an atmosphere, but manufacturers could provide a more accurate figure. [3] which is the site of Universal Industrial Gases, Inc., an Argon supplier says "93% argon and 7% nitrogen at a pressure of 70 kPa (10.15 psig)." This would be 69% of atmospheric pressure. When hot, the pressure would increase considerably. [4] says that tungsten halogen bulbs use several atmospheres of fill pressure. Modern tungsten filaments are a fine wire tightly coiled, which resists the cooling effect of the gas. Edison 17:13, 22 August 2007 (UTC)
Those early vacuum bulbs were a popular plot point in old movies. The good guy is trapped without a gun by the bad guy - so he unscrews a few light bulbs and at a strategic moment tosses them across the room. Aparrently they imploded with such an impressive bang that it sounded much like a gunshot going off! This idea carried on well after that kind of bulb were no longer around! SteveBaker 18:18, 22 August 2007 (UTC)

[edit] Why is warm cheese more flavorful than cold?

Just curious why room temperature cheese has more flavor than the same cheese that has been refrigerated? --24.249.108.133 15:26, 22 August 2007 (UTC)

I imagine it has to do with increased volatility of odour molecules when cheese, or indeed any food is warm. (Most of what we call taste is really smell; taste is only sweetness, saltiness, bitterness, and sourness. Oh and umami). The cold cheese may also affect the way the taste buds sense as well. Flyguy649 talk contribs 15:38, 22 August 2007 (UTC)
I find this is true of many many foods. When beer is ice cold, you taste it less than when it's a bit warmer than that. (Of course if you're drinking ice cold beer you probably don't WANT to taste it..) Friday (talk) 15:45, 22 August 2007 (UTC)
Errr.. it isn't? Or at least, it depends on the cheese.81.83.82.123 21:10, 22 August 2007 (UTC)
In the interest of science, I propose that the submitter eat cold cheese through his nose to see if it taste better. --Tbeatty 06:52, 23 August 2007 (UTC)

[edit] Swallowing toothpaste

Toothpaste (esp. with fluoride) always caution people not to swallow the toothpaste, but what happens to a person if he really does swallow some toothpaste, say, a mouthful? Thanks.

I would imagine Fluoride#Toxicology might give some information. Rawling4851 16:00, 22 August 2007 (UTC)
Also see Toothpaste#Ingredients_and_flavors near the bottom re: nausea. Many toothpastes contain detergents such as SLS that would irritate mucous membranes in the digestive tract if present in high concentrations. -- Flyguy649 talk contribs 16:33, 22 August 2007 (UTC)
At last, I discover why some toothpastes make me urge. DuncanHill 19:37, 22 August 2007 (UTC)
When I was younger no one ever told me not to swallow it. I didn't learn that until a teacher mentioned it in 3rd grade and I seem to be alright. Plasticup T/C 16:43, 22 August 2007 (UTC)
Nothing said on Wikipedia may be taken as medical advice, per the disclaimer at the top of the page. The tube of Crest says ""Keep out of the reach of children under 6 years of age. If more than used for brushing is accidentally swallowed, get medical help or contact a Poison Control Center right away." This also presumably applies to the deliberate swallowing of the product. See also Fluoride poisoning. Edison 16:47, 22 August 2007 (UTC)
Toothpaste, especially the thick pastes of most popular brands, is a choking hazard in young children, which is another reason why it should be kept out of their reach and only very small (pea-size or smaller) quantities used. Flyguy649 talk contribs 19:01, 22 August 2007 (UTC)
I don't know how much flouride is in toothpaste in relation to the flouride in those trays at the dentist, but when I was about 10 years old I swallowed a whole mouthful of delicious orange tasting flouride... the most intense stomach pains I've ever experienced before or since.... x_X --frotht 01:59, 23 August 2007 (UTC)
Far, far less flouride is in toothpaste. StuRat 02:34, 23 August 2007 (UTC)
I knew a guy who had stomach ulcers because of fluoride in the water. He drank bottled water, but the fluoride wasn't filtered out (a lot of filter companies advertise that they don't filter fluoride out like it's a benefit). Juanita Hodges 21:24, 23 August 2007 (UTC)
It generally is a benefit, in the quantity added to drinking water. If I were a betting man I'd wager that the tiny amount of fluoride added to tap water had nothing to do with your friend's ulcers. --24.147.86.187 23:49, 23 August 2007 (UTC)
Astronauts swallow toothpaste regularly. It is simply the easiest way to get rid of it in space, where water is in short supply and everything tends to float around heading for expensive electronics.
Children can develop fluorosis if their adult teeth are not in. While not the end of the world it is not a pleasant-looking condition and cannot be reversed (you can cover it up, but that's about it). --24.147.86.187 23:47, 23 August 2007 (UTC)

[edit] helium ballons

hi all, i think i know the answer, but wish to run it past the collective anyway. Our children have several of the small, cartoon character shaped, helium filled 'foil' ballons; nemo, piglet etc which have retained all their gas and ergo there shape for upto several years, but any large, round 'birthday' ballons we have bought, seemingly made from the same material, have rapidly lost their gas (dependant on temp) after only a few days. I feel that it is a marketing ploy, encouraging you to buy more of the larger ballons, but this theory falls short, when the same ploy could be used to encourage you to buy more character ballons. Has anyone any suggestions for the disparity between their 'inflation life'? thanks Perry-mankster 15:52, 22 August 2007 (UTC)

The foil balloons are made of mylar. Assuming the large ones are also mylar (and not latex like most cheap balloons), it could be a quality issue. If the mylar used for large balloons is made from lower quality mylar, it may have larger pores that allow the helium to escape. Another possibility is that the larger balloons have more seam length. Seams are likely to be the weakest part of the balloon. As for marketing, I have no idea. Flyguy649 talk contribs 16:10, 22 August 2007 (UTC)
Pre-made balloons may have a heat-sealed filling point, whereas balloons bought at florists and the like probably just use some sort of clamp; I'd guess that most of the difference in leak-down rates occurs there. Latex balloons, of course, leak through pores in the latex; remember that helium is the smallest "molecule" so it is very capable of leaking through the tiniest holes. This is what makes it valuable in leak detection: see Helium mass spectrometer.
(Yes, I know I'm using "molecule" in a rather loose way, but I wanted to capture the idea that a diatomic H2 molecule, the next most-likely competitor, is larger than a helium atom.)
Atlant 16:44, 22 August 2007 (UTC)
I wonder whether the 'character' balloons had more paint on them too? It's possible that the paint seals up whatever teeny-tiny holes the mylar might have? It's a long shot though. Mathematically, we know that seam length is smallest (as a proportion of volume or surface area) in a circular balloon - so I don't by Flyguy's 'seam length' argument unless the two classes of balloon are radically different in size (which in itself could explain everything). I like Atlant's answer best - the nature of the seal has to be critical. SteveBaker 16:57, 22 August 2007 (UTC)
Note that helium will leak through the spaces between molecules even if there isn't a hole. You can (slowly) collect helium out of the atmosphere by just pulling a vacuum on a sealed glass container. Part of the reason why people thought they had cold fusion. Gzuckier 17:25, 22 August 2007 (UTC)
If the "round" balloons are latex, there is a lot of pressure forced on the contents of the balloon because the balloon is attempting to shrink down to the original size. This gives the helium inside more incentive to escape any way possible. The mylar balloons I've seen do not stretch. Therefore, they lose helium primarily due to standard osmosis at a much slower rate. But, if both balloons are mylar, this explanation is useless. -- Kainaw(what?) 17:31, 22 August 2007 (UTC)
Yeah - it's very clear that rubber balloons leak helium in a matter of hours where mylar balloons with hold helium for at least a week or two - maybe longer. But the OP said that they were "seemingly made from the same material" - so that doesn't answer the question. (V.Cool about the cold fusion experiment though! Thanks for that Gzuckier.) SteveBaker 18:15, 22 August 2007 (UTC)
You're welcome. A guy I used to know was a physics prof whose specialty in the 80s was cold fusion debunking. Making things even more complicated is that glass which has been exposed to the atmosphere for any length of time is sort of saturated with helium, the way a sponge will be moist after you take it out of a damp environment; so even if they eliminate helium from the outside of the cold fusion reaction chamber, they still have to establish that they have de-heliumed all the glassware in the system sufficiently before detecting anything from the fusion itself. Gzuckier 16:51, 23 August 2007 (UTC)

[edit] oxidative phosphorylation

71.97.110.36 18:10, 22 August 2007 (UTC)I am trying to learn about this process. what is it and what does it do, and is it a desirable outcome? Looking at L-carnitine Fumarate- The product states:"L-Carnitine is an amino acid found in high concentrations in heart and liver tissue, where it participates in metabolizing fatty acids into energy in the mitochondria. L-Carnitine also facilitates the metabolism of carbohydrates and enhances the rate of oxidative phosphorylation". Can you explain this in an understandable statement? I am curious about this, and would like to know if this is a good thing, and is this desirable? I understand what the statement is, but not sure about the outcome?

Original questioner's email address removed - Nimur 18:39, 22 August 2007 (UTC)

Have you looked at Oxidative phosphorylation? This is a particular biological chemical reaction involved in the metabolism, or energy use and storage, by cells. L-Carnitine is a catalyst for that reaction, helping it to occur. I'm not a biochemist, but I would think that any catalyst that enhances the formation of ATP is a desirable thing; that is probably why the cells generate the L-carnitine. Nimur 18:42, 22 August 2007 (UTC)
The dietary supplement industry is built on vague statements such as, "L-Carnitine also facilitates the metabolism of carbohydrates". The question you probably need to ask is if there is any evidence that a carnitine supplement will provide health/fitness benefits. Some small studies of carnitine as a dietary supplement have been published. For example: Effects of four weeks L-carnitine L-tartrate ingestion on substrate utilization during prolonged exercise. The results of more clinical studies are described here. --JWSchmidt 22:18, 22 August 2007 (UTC)

[edit] Vehicles Submerged in Water

Say that you are driving your car and all windows are up. By some accident, your car (and you) ends up in a body of water. I have heard that it is impossible to roll the windows down (in order to escape from the vehicle). Is that true? Is it just hard to do ... or actually impossible? And why? Also -- a related question. If you are in the above predicament, what are the best survival techniques? Thanks. (Joseph A. Spadaro 19:47, 22 August 2007 (UTC))

The extreme pressure of the water forces the window against its frame. There's too much friction to overcome. Even though the electronics and mechanical parts still function, they are unable to generate enough force to slide the glass against the rubber frames. This was recently investigated by the Mythbusters. --Mdwyer 20:00, 22 August 2007 (UTC)
So, are you saying that it is physically difficult to do or physically impossible to do? If the latter ... then, once you are in that predicament, there is literally nothing that you can do? Your fate is sealed, period? And, a related question: does it matter in any way whatsoever if the window is slightly rolled down (say, an inch or so rolled down from the top) ... or that makes no difference at all? Thanks.(Joseph A. Spadaro 20:11, 22 August 2007 (UTC))
Direct link: MythBusters (season 5)#Underwater Car —Keenan Pepper 20:45, 22 August 2007 (UTC)
In such a situation, you should at least try to open up a window, or break the glass. If that doesn't work, chill. The car will gradually fill up, and once it does (doesn't have to be all the way) you'll be able to open the door. Of course, if you end up at the bottom of the ocean, your chances of survival are pretty slim..
hehe, ok next time i'm in a submerged car and the windows won't wind down i'll just chill! ;-) --Cosmic joker 21:52, 22 August 2007 (UTC)
If the car does not leak, then would the trapped air inside be buoyant enough to float the entire vehicle? Nimur 22:22, 22 August 2007 (UTC)
Temporarily, but cars leak, so the point is moot. It's enough that a car doesn't (immediately) sink like a rock, though. — Lomn 22:27, 22 August 2007 (UTC)
Some cars can float for quite a while. It was even a selling point for the VW Beetle: [5] --Reuben 22:38, 22 August 2007 (UTC)
As for survival chances - my first thought was that one could use cell phone (which probablly would be still dry) to call for help, only question is if it would be within reach ---- Xil/talk 22:49, 22 August 2007 (UTC)
Almost certainly useless, as help not on the scene already will take too long. As Keenan's link above indicates, the best survival option once you're submerged is to (1) not panic, (2) allow the car to fill with water (faster is better, so open the window as much as possible) and (3) open the door and exit when pressure permits. Faster is better because you naturally want the car to be as shallow as possible when you do exit the vehicle. — Lomn 22:54, 22 August 2007 (UTC)
Yes, if you sit and wait for help to arrive after you make the call, but you have to wait some while for car to fill with water anyway so you 1) make a call 2) wait for water 3) try to swim out. So if you manage to call help you don't find your self in middle of nowhere soaked to skin and probably injured ---- Xil/talk 23:27, 22 August 2007 (UTC)
There could be a large air bubble in the passenger compartment that may provide breathable air for quite some time (say 20 minutes). StuRat 02:22, 23 August 2007 (UTC)
As for making a call from your sinking car, how much does water weaken a cell phone signal? Someguy1221 03:22, 23 August 2007 (UTC)
I'd expect it to dramatically cut the signal strength, owing to the density of water. Being under 10 feet of water would be about the same as being under 10 feet of soil or concrete. Then there is also the issue of the cell phone being submerged in water and shorting out. StuRat 21:27, 23 August 2007 (UTC)
I'm guessing that if you manage to break the glass, you should cover your face to avoid getting blinded? Skittle 23:41, 22 August 2007 (UTC)
That's a good question- unless in very deep water for some reason, I wouldn't even try breaking the glass. It probably wouldn't kill you because it's safety glass and it would explode into pellets, but it sure wouldn't be pretty. Any better answers? --frotht 01:56, 23 August 2007 (UTC)
More specifically, side and rear windows in cars are tempered glass. Only the front windshield/windscreen is true multi-layer safety glass because safety standards require it to be strong enough to not allow you to burst through it in a crash. The fact that the side windows are tempered glass means they are susceptible to breaking if scratched or hit with a sharp object, BTW. This may be useful in the situation under discussion ;-). MacGyver would simply borrow his woman passenger's diamond ring et voila!
Atlant 12:37, 23 August 2007 (UTC)
Pretty or not, your options are highly limited when you're in the water. If the car for some reason submerges or is slightly buoyant without filling with water, you will only have a finite amount of time before you asphyxiate. And most people given the situation will panic and hyperventilate, which will of course cut down on how long you can hold on the air supply.
And if the car is filling with water, of course, time is severely limited (the car's fill time plus how long you can hold your breath), so drowning is definitely a concern. Getting rescued in either situation is not a trivial issue, and given response time plus the amount of time getting geared up, you may be out of time. If I can't get the doors open after the car starts filling/fills up, I'll take my chances breaking the windshield or a window. Sure, I may get skin/neck lacerations or even blind myself, but it beats the alternative. –Pakman044 04:09, 23 August 2007 (UTC)
If the doors won't open I'd go for opening the windows next, as they aren't likely to be submerged as quickly as the doors. Surprisingly, power windows seem to operate for a few minutes. Also, the rate at which the car fills with water isn't constant. I'd expect it to be slow, at first, as only a small part of the car is submerged, meaning only a few routes for water to get it. Then I'd expect the rate of flooding to increase, but eventually taper off, as a car almost filled with water will have few routes for the air to exit. StuRat 21:34, 23 August 2007 (UTC)
But you want the car to be submerged as quickly as possible so the pressure equalizes --frotht 22:20, 23 August 2007 (UTC)
I wouldn't say that. As long as you have breathable air, there's no hurry, and more time gives you more hope that rescuers will arrive, you can get your seat belt off, you can overcome the tendency to panic, make a plan, etc. StuRat 00:36, 24 August 2007 (UTC)
Write your last will and testament... (You did remember the waterproof marker that works under water right?) Nil Einne 01:21, 24 August 2007 (UTC)

See the following two videos recorded by Top Gear - [6] and [7]. If you end up in water start trying to open the door AS SOON AS POSSIBLE AND GET OUT AS FAST AS YOU CAN. 91.108.209.10 12:51, 23 August 2007 (UTC)

[edit] Alzheimer's Disease

My most basic and simplified understanding of Alzheimer's Disease is this: when you get very old, your mind / mental faculties fail to work 100% properly and you start to lose your memory and to forget a lot of things. That is overly simplified, of course -- but, I believe, the gist of Alzheimer's Disease. Basically, it comes dowm to losing your memory and forgetting / not remembering things. How then, exactly, can Alzheimer's Disease be a cause or reason of death? How would a person's physical body die just because, in their mind, they have become forgetful and lost their memory? Thanks. (Joseph A. Spadaro 21:41, 22 August 2007 (UTC))

Alzheimer's disease is a lot more complicated than simply becoming forgetful. See Alzheimer's Disease and Biochemistry of Alzheimer's disease. Though to answer how forgetting things can lead to death, imagine if you forget how to eat and drink (though that bit can be overcome by medical care). 151.152.101.44 21:47, 22 August 2007 (UTC)
In a nutshell, Alzheimer's is a neurodegenerative disease caused by a biochemical abnormality in protein folding which leads to accumulation of these mis-folded proteins. The exact pathological mechanism is still under investigation. -- MarcoTolo 21:53, 22 August 2007 (UTC)
Number of deaths for leading causes of death. Memory loss is a common symptom, but as the disease progresses other brain functions are increasingly disrupted, making patients more at risk for illness and death. --JWSchmidt 22:27, 22 August 2007 (UTC)
Joseph, what you describe is just the normal decline of cognitive abilities with age. Just forgetting things a bit more often than usual is really quite harmless as compared to real dementia, where forgetfulness is only the very start. Simon A. 08:38, 23 August 2007 (UTC)

I have cared for a large number of people with Alzheimer's Disease and all of them eventually passed away from an associated illness. As the illness progresses the person (and this varies enormously from person to person) becomes less and less able to use their vital functions, feeding, drinking and moving. The nutritional problems can be overcome but eventually the lack of spontaneous movement can raise the person's susceptability to chest infection caused by diminished ventilation. Of course if the hydration problem isn't properly addressed there is a likelihood of renal or bladder infection with the consequent risk of generalised septicaemia and then multi-organ failure. Witnessing this raises the vexed question between quantity or quality of life. Richard Avery 18:48, 23 August 2007 (UTC)

[edit] Quick, slightly vulgar question...

Why do pigs choose to roll around in their own shit? --Kurt Shaped Box 23:49, 22 August 2007 (UTC)

Pigs cannot sweat, so roll in mud to cool themselves, and also use it as a sunblock. In my experience, most pigs will prefer good clean mud, but many are kept in conditions which deny them access to this, so use whatever is available. DuncanHill 23:54, 22 August 2007 (UTC)
Exactly right - pigs only roll in excrement when alternative forms of cooling are unavailable (see this paper for more than you want to know about the mechanics of cooling in hogs). -- MarcoTolo 00:29, 23 August 2007 (UTC)
For more information about terrible pig habits, see Savaging. I'm always trying to get more eyes on this article to help improve it. Nimur 01:54, 23 August 2007 (UTC)
"Terrible" is an opinion, and the line "Aggressive behavior may be due to fear, discomfort, and unsanitary conditions" even implies that it is terrible human habits, not terrible pig habits, that are to blame. — PhilHibbs | talk 13:19, 23 August 2007 (UTC)
Indeed, although IANAPF I have known enough in my time to realise that such behaviour is a sign of poor husbandry. DuncanHill 13:22, 23 August 2007 (UTC)
I keep trying to find a reliable source for information about savaging in budgerigars to add to that article. I have a textbook somewhere that mentions it - but I've looked high and low for the thing today and still can't find it. Young hens in particular are known to savage their own chicks. --Kurt Shaped Box 17:05, 23 August 2007 (UTC)
On the other hand, I've seen dogs eat and roll in excrement. I can only speculate that this helps disguise their "dog smell", making it easier for them to sneak up on prey. StuRat 02:14, 23 August 2007 (UTC)
...who wouldn't notice a giant turd sneaking up on them. Someguy1221 03:20, 23 August 2007 (UTC)
They'd just think it was a visit from Mr Hankey. StuRat 00:31, 24 August 2007 (UTC)
Or a Baby Ruth bar DuncanHill 12:28, 24 August 2007 (UTC)
actually, you should see them around horses. Makes a lot more sense then. And dogs seem to like it more. --Tbeatty 07:45, 23 August 2007 (UTC)