Wikipedia:Reference desk/Archives/Science/2008 June 6

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[edit] June 6

[edit] Ballpoint pen ink

I've noticed that the ink from many ballpoint pens-- as well as from cheap disposeable fountain pens-- has a reddish or coppery-brown sheen, regardless of the ink's color. However, this vanishes when the ink dries or sinks into the paper(although it remains visible on non-porous surfaces). What component of the ink causes this metallic appearance? 69.111.189.55 (talk) 02:12, 6 June 2008 (UTC)

Well, until a chemist comes by, I found a patent for the composition of ball point ink: "An oil-based ink composition for a ballpoint pen which comprises a colorant, a resin and a solvent [of an alcohol... blah blah)" doesn't tell us much, but Ink brings up iron oxide. So for my money, oil sheen and/or iron oxide something. Julia Rossi (talk) 09:22, 6 June 2008 (UTC)
Mmmh - might be formation of dye at the surface - ie the dye might be a surfactant - inks probably contain surfactants. Also when ink liquid evaporates some dye might come out of solution - a bit like the skin on a milk pudding or something.. When it dries all the different colours are 'in the same place' so you won't notice the effect. You knew that inks (black) are made from different colour dyes (red/green/blue etc) - not all but most.87.102.86.73 (talk) 20:10, 9 June 2008 (UTC)

[edit] Huge Problem

Up until just recently, I've had a huge problem. The temperature in my bedroom was 90 degrees Fahrenheit. (Only a slight exaggeration.) I finally broke down and got a window air conditioner, and while that solved the temperature problem, now I have another huge problem. Every five minutes (only a slight exaggeration), the AC, apparently, draws too much electricity. This causes my lights to dim, among other things. And now it's starting to effect other things. For example, it has caused my computer to turn off and restart right when I'm in the middle of things. Is there anything I can do (that won't get me electrocuted) to resolve this? Digger3000 (talk) 03:35, 6 June 2008 (UTC)

Ask an electrician for help to upgrade your power, or secondly add a small UPS to your computer, so that it can withstand the power sags. Graeme Bartlett (talk) 06:01, 6 June 2008 (UTC)
Household wiring is supposed to deliver a reasonably steady voltage even when a heavy load comes on. Your description makes me worry that some part of your wiring is actually defective and unable to pass the proper amount of current; or alternatively that your wiring is overloaded and the air conditioner should be blowing a fuse or tripping a circuit breaker, but it isn't because the wrong size fuse/breaker is in place. Either of those conditions could be a fire hazard. Obviously I'm not in a position to say if there is a real hazard, but I really think you need to get an electrician in and have this looked at. --Anonymous, 07:36 UTC, 2008-06-06.
Anonymous is right. You describe a dangerous situation. See "Overcurrent". --Milkbreath (talk) 10:31, 6 June 2008 (UTC)
From my limited knowledge, I believe air conditioners are usually installed by electricians because they draw more current than normal. They circumvent the normal wiring of the house, using stronger cables.59.100.206.238 (talk) 11:15, 6 June 2008 (UTC)
Not window air conditioners. Those are just big appliances with standard plugs. --98.217.8.46 (talk) 19:58, 9 June 2008 (UTC)

I figured you might suggest a UPS. But the thing is, I do have my computer plugged into a UPS. Even so, my computer has completely lost power a few times. Not every time the power sagged, but a few times. And even when the UPS does do its job, it beeps every time the power sagged. And as annoying as that is, it'll probably be even more annoying when my house is burning to the ground. Yeesh, I should probably get that checked out, soon. Do you think it would help at all if there were fewer things plugged in in my room? There's not really much I can unplug, but I could try it. Digger3000 (talk) 11:56, 6 June 2008 (UTC)

Yes, as a temporary measure before getting an electrician to check your wiring I would definitley do whatever I could to reduce the load. -- Q Chris (talk) 13:34, 6 June 2008 (UTC)

A qualified electrician could monitor the voltage at the air conditioner outlet and at the main panel to determine the quality of the incoming voltage and the voltage drop from the panel to the outlet. I do not recommend an amateur trying to measure/correct these possible electrical problems because electricity can kill you. Low voltage at the air conditioner outlet can cause the motor to draw more current to maintain its mechanical output to the airconditioner compressor. The additional current causes the voltage seen by the air conditioner to drop, in a vicious circle until the current is so high that a breaker trips or the air conditioner motor overheats and a thermal protective device in it cause it to trip offline to cool down. Then the cycle repeats. Blowing a fuse or tripping a circuit breaker at the house utility panel may occur. The causes may be multiple, and in combination: 1)A long run of small (#14) wire from the utility panel to the air conditioner outlet. (Helped by having an electrician run a #12 20 amp circuit from the panel to the outlet. Putting in a larger fuse would be idiotic, of course). 2)Use of an extension cord to run the AC (Try plugging it directly into an outlet) 3)The circuit may be loaded down with other loads, such as the computer you mentioned. (Remedy:Get the air conditioner on its own circuit). 4)The air conditioner might be defective, inefficient or too large. Try a different one of the same size if available. Try a high efficiency one with a higher energy efficiency rating, which should draw less current, or try a smaller air conditioner. 5)The service wires from the transformer to the house might be too small, resulting in too-low voltage when the building draws high current. This is a job for an electrician or the utility, depending on where you live. 6) There might be a loose neutral connection between the utility and the house or inside the house wiring. Symptoms might be some light getting brighter when the air conditioner circuit voltage drops. A job for an electrician and the utility. 7)The utility might be supplying low voltage, due to loose connections in the service wires, your transformer being too small, a heavily loaded circuit or to your being near the end of the circuit, or to a lack of capacitor banks, or to intentional voltage reductions (brown outs) or to poor voltage regulation at the substation or along the feeder. If this is diagnosed by actual measurements, complaints to the utility, or to your public officials if the utility won't correct their deficiency,might get corrective action. If you can report to the utility that an electrician has measures illegal low voltage for extended periods (over 1 minute) at the main panel with an accurate RMS volt meter, you could demand that the set a recording voltmeter at the meter, to confirm the finding, and that they then correct it. In many US locations 114 volts (5% below 120) is the minimum legal voltage at the electric meter. This allows the voltage to drop a bit in the house wiring and still be able to operate the air conditioner at the other end of the house. Edison (talk) 13:42, 6 June 2008 (UTC)

Here's your answer. But as a stop gap solution you might just try putting it at a colder setting to make it run longer. It's the compressor start-ups that draw the most current. Or let it cool the room first, then turn it off and cool yourself with a fan for a few hours. Fletcher (talk) 14:12, 6 June 2008 (UTC)
I agree with Edison that an easy short-term solution is to put the AC on a difference circuit. Even if your electricity was working correctly you'd be blowing fuses/tripping circuits with that arrangement as you describe it. You'll either need another circuit installed or need to run an extension cord to a difference one. --98.217.8.46 (talk) 19:58, 9 June 2008 (UTC)

[edit] Another Unknown Equation

In the spirit of the question above, what's the meaning of engie's "favourite" equation? --antilivedT | C | G 05:22, 6 June 2008 (UTC)

I don't know what it means, but it's not an equation (no equals sign). Algebraist 13:27, 6 June 2008 (UTC)
It is apparently an expression for the amount of light reflected from an object illuminated by several sources. It's used in ray tracing. [1] --Heron (talk) 20:18, 6 June 2008 (UTC)

[edit] Holographic projection...

i would like to know if there is a technology confirming to holographic projection such that the projection is not made on any solid or liquid medium as in the case of Musion's 'Eyeliner foil' —Preceding unsigned comment added by 61.17.218.119 (talk) 07:02, 6 June 2008 (UTC)

[edit] Yeast and brewing

Does anyone know how to balance this reaction? C12H22O11 = C2H5OH + CO2 All the reactions I can find use glucose. But when making beer, they don't use glucose, they use maltose. I can't work out how to balance it though.

Thanks, Wikiwikijimbob (talk) 12:23, 6 June 2008 (UTC)

Don't discount the possibility that you might need a water molecule on one side or the other - on a brief look it seems to balance similarly to glucose if you add a water molecule on the left hand side. Not sure, though, but it's worth checking. ~ mazca talk 13:03, 6 June 2008 (UTC)
I'm going to second and say that you're going to need a water molecule on the reactant side and also may have copied down the formula of the original carbohydrate wrong. Carbohydrates have a C:H:O ratio of 1:2:1. EagleFalconn (talk) 14:26, 6 June 2008 (UTC)
No, that's the correct formula of maltose. Algebraist 14:30, 6 June 2008 (UTC)
The C:H:O ratio of 1:2:1 is only true for monosaccharides, and only in its most narrow meaning (discounting e. g. deoxy sugars). Icek (talk) 18:10, 6 June 2008 (UTC)
Thanks, it's much appreciated. Wikiwikijimbob (talk) 19:27, 9 June 2008 (UTC)

[edit] effect of overly large stimulus

Assuming you have a way to bypass the senses, imagine you have a microphone, a mechanical tounge, an artificial nose and a camera attached directly to your brain. What would happen if you received 100000000dB,the full light u a supernova and any other overly large stimulus which would normally devastate your receptive organs? 193.188.46.64 (talk) 12:37, 6 June 2008 (UTC)

Your guess is as good as anyone elses, it is difficult to give definitive answers to such speculative questions. Jdrewitt (talk) 13:08, 6 June 2008 (UTC)
For any realistic artifical sensory apparatus, though, it will be devastated by such a stimulus, just as an unassisted human would be. Algebraist 13:23, 6 June 2008 (UTC)
And even if it wasn't, a proportional signal to your brain would probably involve sufficient current that brain damage would ensue. Not to mention the effects on the rest of your body of being close to a supernova or a 100,000,000db noise! ~ mazca talk 13:26, 6 June 2008 (UTC)
I think the question is assuming that the artificial sensory apparatus are robust enough to cope with the stimulus however large and it is purely asking how would the brain interpret the signal (not how the rest of the body will cope). It really depends on how the sensor communicates to the brain which is too speculative since such a technology does not exist. Jdrewitt (talk) 13:35, 6 June 2008 (UTC)
Does the OP realise that the dB scale is logarithmic, and a 108dB noise would have energy immeasurably greater than that of the observable universe? Algebraist 13:47, 6 June 2008 (UTC)
(ec with algebraist)Just to put this in perspective, the entire output of the sun is around 638dBμ. Even the largest galaxies with 1012 stars still output less than 1000dBμ. I doubt that the amount of power represented by 100,000,000dB could be generated in the entire universe. Exposed to that kind of output, you are going to have bigger worries than what your sensors are made of. Sensors, you, your brain, your planet and your galaxy are all going to be vapourised. SpinningSpark 13:50, 6 June 2008 (UTC)
I think the most serious problem is that it'll cause the gravitational collapse of the entire universe. Algebraist 14:04, 6 June 2008 (UTC)
To be charitable to the OP I think we should assume the energy is just larger than what a person would normally encounter (but not so large as to destroy the universe!), and that the subject's body is protected from it, so he experiences it only through the artificial sensors. Not being a neuroscientist I really can't say what would happen; however, it seems unlikely the brain can distinguish signals at levels that would kill the physical body. I would think there is an upper limit beyond which it makes no difference how strong it is; the brain will interpret it as extreme light, extreme noise, etc. The artificial sensors would have to progressively step-down the signal so as not to damage neurons. A brighter light would have to be stepped down further, resulting in no difference in perception. But i don't know what happens at that upper limit of stimulation -- would it provoke a fight-or-flight response, a panic attack, a seizure? Fletcher (talk) 14:56, 6 June 2008 (UTC)
They would be rather poorly designed sensors if they provided enough current to damage the brain, they would reach their maximum safe output levels and that would be it. You'd see nothing but white and hear probably nothing but a whoosing sound of all the matter traveling past or perhaps a banging noise from the shockwave, if the sensors were calibrated to normal human sight and hearing. If they were calibrated for optimum observation of a supernova, then you would see the supernova, the amount of energy that the sensors receive does not have to correlate to a larger amount of energy put into the brain. Brain-computer interface may be enlightening. -- Mad031683 (talk) 16:39, 6 June 2008 (UTC)
Higher intensity of sensory input causes higher frequency of neuron firing, but no change in the action potential. The frequency is limited by the time needed to restore the resting potential, at least a few milliseconds. Icek (talk) 18:04, 6 June 2008 (UTC)
While I don't think these directly answer the OPs question, they may be interested in visual prosthesis and neural prosthetics as they describe the current state of the art. SpinningSpark 16:58, 6 June 2008 (UTC)

I was indeed assuming that the sensors where robust enough, and I just typed in an insanely huge number to stress that no person could receive such a stimulus naturally. So assuming the electronic interface communicates using normal neurons the largest signal possible will be determined by the inactive time of neurons? I was mostly interested in how would the brain change to accomodate these stimulus. How does the brain change in response to normal stimulus? Bastard Soap (talk) 20:07, 7 June 2008 (UTC)

[edit] flowers

which part of the flower is the pollen & the egg cells produced? —Preceding unsigned comment added by 96.10.123.85 (talk) 14:17, 6 June 2008 (UTC)

Have you looked at flower and plant anatomy? Those might be good places to start. Friday (talk) 14:39, 6 June 2008 (UTC)

[edit] Hypothetical Suicide only

This question has been removed due to the possibly dangerous outcomes that could amount from any answers given. Not only could the answers be seen as morally fragile, but there may also be legal implications should anyone stumbling upon the page take action with what they've heard. For these reasons I have removed the question, should anyone disagree they can talk to me further on my talk page. My sincere apologies to the OP. Regards, CycloneNimrod talk?contribs? 21:12, 6 June 2008 (UTC)

[edit] Diagnosticians

What do diagnosticians actually do and why are they necessary when there are plenty of doctors who are specialised in different fields of medicine? Thanks. Clover345 (talk) 17:48, 6 June 2008 (UTC)

There are consultants for every field indeed. But what if you don't know which consultant to refer a patient to? Many symptoms are vague: Malaise, lethargy, widespread pain.... A diagnostician specialises in signs and symptoms rather than any specific disease or organ system. In many ways general practitioners act as diagnosticians (especially in the UK and Ireland where you cannot see a consultant directly, only by GP referral). Fribbler (talk) 17:59, 6 June 2008 (UTC)
According to the entry on diagnostician, it's simply a generic term for someone who makes diagnoses, and that someone is most likely a doctor. ~Amatulić (talk) 18:02, 6 June 2008 (UTC)
Could an A&E consultant act as a diagnostician and are there diagnosticians other than GPs in the UK? Clover345 (talk) 18:11, 6 June 2008 (UTC)
An A+E doctor (any rank) is a good example of a diagnostician. As far as I know, here in Ireland (which usually means it's the same in the UK) there arn't any "diagnosticians" by title such as there are on House. Fribbler (talk) 18:19, 6 June 2008 (UTC)
Here in the U.S., "diagnostician" is a descriptive term, not a specialty.Scray (talk) 03:41, 7 June 2008 (UTC)


[edit] BACILLI MICROORGANISMS

1)HOW DOES IT LIVE?

2)WHERE DOES IT LIVE (ITS ENVIRONMENT)?

3)DOES IT THRIVE BEST ALONE OR WITH OTHER MEMBERS?

4)WHAT ASSISTS IN ITS EXISTANCE?

5)HOW DOES ONE BECOME INFECTED WITH IT?

6)(CHAIN INFECTION) HOW DO MICROORGANISMS CAUSE INFECTION AND HOW TO PREVENT ITS SPREAD?

Genisa (talk) 19:51, 6 June 2008 (UTC)

Mmmm. Tasty, tasty homework. Sorry, we won't answer these for you but we can point you in the direction. Unfortunately, I don't know enough about this topic. Regards, CycloneNimrod talk?contribs? 20:11, 6 June 2008 (UTC)
No, we cannot really answer these for you. Besides, it'll be worth your while to do a little research. Allow me to point you in the direction of a great and very informative website. [2]. Wisdom89 (T / C) 20:21, 6 June 2008 (UTC)

[edit] Largest molar mass

What known compound has the largest molar mass? 65.31.80.94 (talk) 20:49, 6 June 2008 (UTC)

Periodic table. Wisdom89 (T / C) 20:50, 6 June 2008 (UTC)
He asked for a compound. That can't be determined solely from the periodic table, can it? Ζρς ι'β' ¡hábleme! 21:04, 6 June 2008 (UTC)
Well excluding answers like macroscopic crystals and neutron stars, the answer is probably a protein. The largest one in the human body is Titin at nearly 3 million Dalton. Any advances? SpinningSpark 21:35, 6 June 2008 (UTC)
DNA. Dragons flight (talk) 22:18, 6 June 2008 (UTC)

Backelit or any other cross linked polymere or a piece of graphite a sio2 crystal ..... there are many possible canidates.--21:38, 6 June 2008 (UTC)

I think for the purposes of this challenge that we can exclude polymers, as crystals are also excluded and look for a compound with a well defined formula, and therefore molecular weight. Earlier here we were trying to identify the densest gas. Graeme Bartlett (talk) 22:54, 7 June 2008 (UTC)


[edit] Natural occurence of dry ice?

Does solid CO2 occur naturally anywhere on Earth? At high pressures, for example? Or the at -89.2C (cf. sublimation point of CO2 -78C), would CO2 precipitate from the air?

Cheers!

Aaadddaaammm (talk) 22:08, 6 June 2008 (UTC)

I have heard that the small partial pressure of CO2 means that only a tiny amount of Carbon Dioxide solidifies, even at extremely low temperatures, so any dry ice formed would be invisible. Can't remember where I heard/seen that, though. Fribbler (talk) 01:12, 7 June 2008 (UTC)
Probably not naturally, although there may occasionally be liquid carbon dioxide in Carbonatite volcanic eruptions which start from the mantle. After the sun dies however there should be carbon dioxide frost formed, if the earth survives. Graeme Bartlett (talk) 23:00, 7 June 2008 (UTC)
Even if the Earth survives, the atmosphere will probably be completely blown away, so there won't be any CO2 to sublime. --Tango (talk) 10:42, 8 June 2008 (UTC)
This chart indicates a vapor pressure of about 0.02 bar = 2 kPa at 154 K. The atmospheric partial pressure is only about 38 Pa. So even at -119°C it wouldn't solidify, for the same reason that water doesn't condense as long as relative humidity is below 100%. Icek (talk) 21:22, 8 June 2008 (UTC)