Wikipedia:Reference desk/Archives/Science/2008 July 7

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July 7

what kind of snake?

Does anyone know what kind of snake this is? I spotted it in the forest near Multnomah Falls in Oregon, United States. Shown with a US nickel. Thanks! Dar-Ape 01:12, 7 July 2008 (UTC)

Almost certainly a worm snake. See more here. --Sean 14:22, 7 July 2008 (UTC)

Well, according to our article Carphophis, the American species of worm snakes range no farther west than the eastern Great Plains. I don't think one could pop up in Oregon. I'm no herpetologist, but of all the Oregon snakes in this list yours most resembles, to me, a rubber boa. Deor (talk) 22:47, 8 July 2008 (UTC)

A Rubber Boa seems most likely. Thanks a lot! Dar-Ape 02:11, 9 July 2008 (UTC)

What percent of heart attacks go undetected each year?

I'm not talking about ones where the person dies, and they just guess; I mean, is there some estimate of how many people might have really mild ones and not know it. I read that Bo Schembechler likely had one. I suspect it's someone common in high stress jobs to just think you're having angina when in fact you're having an actual heart attack.

If untreated, would the person who had one just recover naturally, or would there still be problems? I guess if they 'slow it down" for a few weeks then are back at it, they could for a while, right? Or, would an untreated, yet mild, heart attack still cause problems later? A friend I know thinks they might have had one, though they thought at the time it was angina; they eventually went into another field that was less stressful, and any bouts with shrotness of breath left.209.244.30.221 (talk) 01:15, 7 July 2008 (UTC)

I don't know enough about the topic to comment on the rest of your questions, but I'm pretty sure that if someone dies of a heart attack, they don't have to guess: a post mortem medical examination is going to show that as the cause of death pretty conclusively. (Also, if your friend thinks they might've had a heart attack, they should go and see a doctor. Frankly, I'm a little shocked if they haven't figured this much out by themselves. I mean, exactly what does it take for them to start to consider seeing a doctor if that doesn't do it?!) -- Captain Disdain (talk) 01:48, 7 July 2008 (UTC)

I know people say this all the time, but Wikipedia will not give you medical advice. If your friend thinks he has a medical problem he ought to consult a licensed physician not a bunch of anonymous folks on the internet, brilliant though we are. That said, I doubt the statistic you are looking for exists. By definition, data is not collected on heart attacks that go undetected, so it is very hard to compile information on them. Plasticup ^T/C 02:56, 7 July 2008 (UTC)

Captain Disdain, I am not shocked at all that his or her friend hasn't "figured this out," considering my best friend's dad actually *knew* he was having one and *still* drove himself to the hospital, a very dangerous thing to do! (Don't try this at ome.) And, he'd been in denial for a couple days before, when he was having chest pains, despite his family insisting he go. We don't know how much in the past this friend had one, so perhaps he cut back on a lot of stuff, got more exercise, when when he stopped having angina after a while, forgot about it. But, that is definitely not a safe way to handle your health.Somebody or his brother (talk) 14:10, 7 July 2008 (UTC)

Up to ~40% of heart attacks are not recognized [1]. Any heart attack has the potential to cause lasting damage. Looking for that damage is in fact the easiest way to detect the signs of a heart attack in patients who had an episode and didn't recognize it. If your friend did have a heart attack, there is a good chance that an EKG would be able to confirm, and as always we'd encourage you to speak to a doctor. Dragons flight (talk) 03:37, 7 July 2008 (UTC)

Neat study. Thanks DF. --Shaggorama (talk) 04:32, 7 July 2008 (UTC)

Similiar heartbeats

Is it possible for tow unrelated people to share very similar cardiac patterns for a prolonged period of time. 69.157.226.161 (talk) 01:49, 7 July 2008 (UTC)

I would imagine any healthy people are likely to have similar cardiac patterns. Any difference from the norm usually indicates a problem. --Tango (talk) 01:55, 7 July 2008 (UTC)

The resting heart rate is similar amongst humans, though it depends on body size and shape. You're heart rate is also constantly changing depending on your current level of activity. It is possible for your heart rate to appear to match someone else's exactly, but only briefly. --Russoc4 (talk) 02:44, 7 July 2008 (UTC)

Heart rhythms are so similar that EKG machines are tuned to pick up very minor fluctuations. I have a slightly long Q wave by 2 milliseconds (usually) and it is always picked up on an EKG. So, if you aren't looking into the millisecond range for differences in heart rhythms, you'll likely see nearly identical rhythms running at different rates (ie: 70 beats a minute compared to 80 beats a minute). -- kainaw™ 04:27, 7 July 2008 (UTC)

Can vets tell what Animal species

—Preceding unsigned comment added by 98.203.9.163 (talk) 05:31, 7 July 2008 (UTC)

Depends on the animal, probably. Dogs and cats—of course. All of the ones you see are of the same species (Canis lupus familiaris, Felis catus, respectively). Cows? Horses? Probably not, unless they are a large animal vet. Exotic animals? Maybe if they work at a zoo, but even then, I doubt they know them all off hand.--98.217.8.46 (talk) 16:04, 7 July 2008 (UTC)

Hertz.

What is the difference between 50Hz and 60Hz?

Could a 60Hz supply damage a 50Hz appliance? —Preceding unsigned comment added by 41.241.32.81 (talk) 06:09, 7 July 2008 (UTC)

Hertz is a measure of frequency. In this case, it describes the number of times that an AC current changes polarity per second. It's effect depends on the appliance, but in principle yes, it could. More important is the difference in voltage that often goes with the difference in frequency. Some appliances will not work at all, some at a different speed, and some may be damaged. Modern electronic devices usually have power supplies that accept a range of voltages and frequencies (50-60Hz, 100-240V nominal). Check your appliance for a type sign. --Stephan Schulz (talk) 10:58, 7 July 2008 (UTC)

If you say the type of appliance then someone here will probably know whether it is likely to be damaged or not. Itsmejudith (talk) 11:01, 7 July 2008 (UTC)

Hertz is the number of cycles per second. The polarity changes twice in each cycle, so 60Hz changes polarity 120 times in a second. — DanielLC 17:48, 7 July 2008 (UTC)

Thanks. I was grasping for the correct word "cycle" (and failing), so I carefully changed "denotes" in my original draft to "describes" in order to be unwrong. ;-) --Stephan Schulz (talk) 21:47, 7 July 2008 (UTC)

chemitry

why are most types of glassware use in a chemical laboratory made of pyrex? —Preceding unsigned comment added by 125.60.237.218 (talk) 13:14, 7 July 2008 (UTC)

It's not always 'pyrex' though most borosilicate glasses are often refered to as pyrex.. the reason is its thermal shock resistance..

I recommend reading both the links pyrex and borosilicate glass.87.102.86.73 (talk) 13:25, 7 July 2008 (UTC)

note a lot of specialised lab glass ware will be made out of quartz, but only very specialised stuff.87.102.86.73 (talk) 13:20, 7 July 2008 (UTC)

The thermal shock resistance is true, its also the fact that borosilicate glass is even more chemically inert than regular glass, especially to things like hydroxide. Quartz is often used for things that need to be optically pure (like spectrometry cuvettes). EagleFalconn (talk) 14:05, 7 July 2008 (UTC)

Need Help Identifying Scary and Fast Bug.

Every once in a while, before I turn on the water to take a shower, a bug that looks really hairy or has a thousand legs darts out of nowhere and scares the poop out of me. It is realy, really fast and I am not around a camera to take a picture. Do you know what kind of bug this is? BTW - I live in New England, USA. --Anthonygiroux (talk) 13:17, 7 July 2008 (UTC)

Please get rid of the P word. 208.76.245.162 (talk) 13:33, 7 July 2008 (UTC)

which one 'poop' or 'picture'? Richard Avery (talk) 14:12, 7 July 2008 (UTC)

A house centipede? Deor (talk) 13:46, 7 July 2008 (UTC)

Sounds about right to me. I also live in New England and occasionally got those guys in bathrooms where there were cracks in the walls and things like that. They eat bugs so they're supposedly helpful but damned if they aren't the ugliest, creepiest creatures. And if you swat them, they fall apart into about a million tiny pieces... --98.217.8.46 (talk) 16:10, 7 July 2008 (UTC)

Hi. Ah yes, that's probably what I thought they were. I live in Southern Ontario, I've seem them around before, and they're an invasive species. Just as I suspected, the article says they are venomous and can bite, but are usually not dangerous. Thanks. ~AH1^(TCU) 17:00, 7 July 2008 (UTC)

I find centipedes are difficult to kill because they are fast, smart enough to hide behind things, and seem to know when they are being hunted. I use Hot Shot Wasp & Hornet spray, which can spray a narrow stream several feet. This allows me to hit them before they escape, and it kills them quickly. Open a window after spraying. StuRat (talk) 03:14, 8 July 2008 (UTC)

"Universe in My Thumb"

Someone told me that there is (or could be) a whole universe in my thumb. Do you know what they mean by that? --Anthonygiroux (talk) 13:19, 7 July 2008 (UTC)

I personally have no idea. Maybe it was an idiom? — CycloneNimrod  ^Talk? 13:24, 7 July 2008 (UTC)

They might have meant something like the concepts described in Parallel universe (fiction)87.102.86.73 (talk) 14:06, 7 July 2008 (UTC)

Sounds like somebody's been watching National Lampoon's Animal House. I can't find a transcript, but there's a scene where some of the characters get high, and then Pinto realizes that "our universe could be a cell in the thumbnail of some larger being?" --LarryMac | Talk 14:24, 7 July 2008 (UTC)

Both MIB and MIIB show this philosophical idea in their closing scenes. Layman's models for atoms and solar systems look quite similar but I'm sure if you said they are similar a scientist would throw a fit. So, really this seems more like a humanities question than a scientific one. -LambaJan (talk) 17:38, 7 July 2008 (UTC)

The humanities guys might talk about it a little more, but ultimately I think we could all come to the same conclusion. Plasticup ^T/C 18:21, 7 July 2008 (UTC)

There are theories about universes within universes - I believe a universe within our universe would look like a black hole. It's all highly theoretical and bordering on unscientific, though. I can't find any mention of the theory in Wikipedia, oddly... --Tango (talk) 21:08, 7 July 2008 (UTC)

We don't need Wikipedia here. What about the episode of The Simpsons that opens with the universe morphing into Homer's brain? That's where I get my science knowledge anyway, same as I get my religious knowledge from Life of Brian! :) Franamax (talk) 02:07, 8 July 2008 (UTC)

It's a pretty classic, and admittedly mind-blowing concept, especially if you're, oh, about 12 when you first come across it. (Or pretty thoroughly baked.) Anyway, there's no scientific basis for it, but the idea is that since there's a vast microscopic, atomic and even sub-atomic level of existence all around us that we cannot really perceive, there could be tiny, tiny universes anywhere. (Comic book readers may be familiar with Marvel's Microverse, which may be based on the concept, or perhaps introduced it to awed kids everywhere.) And, yes, as Delta House helpfully points out, that means that our universe could just be a speck under some unimaginably vast being's fingernail -- we could merely be a part of some much, much larger system that we will never be able to perceive or understand. Repeat until you go "Whoa. Dude." -- Captain Disdain (talk) 06:35, 8 July 2008 (UTC)

Perhaps:

To see a World in a Grain of Sand

And a Heaven in a Wild Flower,

Hold Infinity in the palm of your hand

And Eternity in an hour.

-William Blake (1709-1784)

Sandman30s (talk) 12:21, 8 July 2008 (UTC)

Ever read Horton Hears a Who! by Dr. Seuss? --Shaggorama (talk) 12:24, 8 July 2008 (UTC)

How could this be?

Tomoji Tanabe is 112 and seems to be extremely healthy. My grandmother is 86 and is in hospital sick. Higher ages seem to be more common in females, so how was this jumble caused? 208.76.245.162 (talk) 13:31, 7 July 2008 (UTC)

Tomoji is an Outlier, and furthermore, comparing two individuals' lifespan will often deviate from what might be expected. Not to be heartless, but compared to average lifespan, 86 is pretty good. Dar-Ape 14:04, 7 July 2008 (UTC)

Genetics plays a big role - we can't really say much more without knowing the history of your family's health and Tomoji's, as well as their personal habits. So many things go into this that it's very hard to pin down one thing and say, "This should make this person live longer."

However, I completely understand your need to, emotionally, with your grandmother sick like that. Sometimes, we really can't understand why anyone has to grow old and die. We can only answer like in the classic Sesame Street episode about the death of the lovable Mr. Hooper - "just because." You're in my prayers.Somebody or his brother (talk) 14:16, 7 July 2008 (UTC)

"...new life makes losing life easier to understand." - If I could", from the album In Between Dreams by Jack Johnson --antilived^{T | C | G} 23:59, 7 July 2008 (UTC)

In answer to the second question [2] is of interest Nil Einne (talk) 18:40, 8 July 2008 (UTC)

sunrise and sunset

my teacher said that we see the sunrise and sunset approx. two minutes earlier and two minutes later respectively. so daytime is extended by a total of four minutes. this happens due to atmospheric refraction of light. but, at noon, we see it as it really is (there is no early or late viewing). why is this so? —Preceding unsigned comment added by 122.50.250.178 (talk) 13:41, 7 July 2008 (UTC)

Atmospheric refraction, I think. Dar-Ape 14:07, 7 July 2008 (UTC)

Also, the apparent position of the sun in the sky is about 500 seconds behind where it actually is due to the amount of time it takes light to travel from the sun to the earth. Snell's law would probably be a good read as well, and the basis for atmospheric refraction. Note that when the index of refraction changes, the speed of light changes as well. I'm somewhat skeptical of there being no time difference at noon as the sun rarely strikes the atmosphere at 90º even at noon in most places (and even if it did, wouldn't there still be a time delay because of the change in n?). EagleFalconn (talk) 14:13, 7 July 2008 (UTC)

The time it takes light to travel to the Earth makes it look like the sun is where it was 500 seconds ago, which is pretty much where it is now. The Sun isn't moving; the Earth is spinning. — DanielLC 17:42, 7 July 2008 (UTC)

That 500 seconds is a red herring. The movement of the sun is not what causes sunrise and sunset. The relevant movement is entirely on our end. APL (talk) 18:07, 7 July 2008 (UTC)

Doesn't change the fact that what I said is true. Yes, the effect is about 0.4 arcminutes, but its still worth noting as the atmospheric refraction article also deals with travel time and how the index of refraction causes the light to bend above the horizon. EagleFalconn (talk) 21:11, 7 July 2008 (UTC)

But the 500 second delay won't increase the length of the day by any amount of time, because you have the same delay to shorten it in the morning. It only really has to do with refraction. --Wirbelwindヴィルヴェルヴィント (talk) 17:08, 8 July 2008 (UTC)

"Also, the apparent position of the sun in the sky is about 500 seconds behind where it actually is due to the amount of time it takes light to travel from the sun to the earth." The light time is accurate, but the apparent position of the Sun is its actual position. Suppose that at 00:00, two rays of light leave the Sun. One is headed for the current position of the Earth, while the other is directed towards the location Earth will be at 500 seconds later. At 00:08:20, the first ray completely misses any human eyes, while the second is detected. Notice that the path taken by the second ray is exactly the same as a line drawn between its source and Earth, so it is the the Sun's true position that is noted by observers. --Bowlhover (talk) 05:23, 9 July 2008 (UTC)

Hertz.

Could i change a 60Hz generating set to 50Hz?41.241.32.81 (talk) 15:11, 7 July 2008 (UTC)

Depends quite what you have operating at 60Hz. Read the user manual, whatever it is. -mattbuck (Talk) 15:32, 7 July 2008 (UTC)

Stores like radio shack have outlet converters for travelers to use. I'm sure you can find one on ebay or something as well. -LambaJan (talk) 17:42, 7 July 2008 (UTC)

A large 60 Hz alternator (such as is found in peakers or baseload generators) would likely be damaged if operated for any prolonged period at any substantial loading at 50 Hz. They have underfrequency relays which automatically trip them off line at a higher frequency than 50 Hz. Not familiar with the limitations on operating small alternators at reduced frequency, but I have my doubts. In some cases it might be possible to rewind a generating set for 50 Hz operation. Utilities also used rotary convertors to change the frequency, such as 60 Hz to 25 Hz and vice versa. Edison (talk) 19:11, 7 July 2008 (UTC)

The smaller gensets match the speed of the engine to the required frequency. So slowing the genset down would reduce the frequency, the trouble is the voltage will drop as well.Polypipe Wrangler (talk) 02:45, 11 July 2008 (UTC)

menigocele

why is cough impulse present in a meningocele —Preceding unsigned comment added by Dr.Rameshs (talk • contribs) 15:49, 7 July 2008 (UTC)

I presume you are referring to meningocele as in spina bifida? I'm not entirely sure, presumably due to stimulation of one or more thoracic nerve roots. The effect can be simulated too, I believe. See this. — CycloneNimrod  ^Talk? 16:21, 7 July 2008 (UTC)

Finding a positive cough reflex is diagnostic in certain types of meningoceles. I am unable to detect any websites which cover this issue. I assume it is related the raised intrathoracic pressure caused by coughing. This pressure is then transmitted to the cranium via the blood vessels and thus to the meniningocele via the cerebrospinal fluid channel. The positive cough reflex would indicate that the meningocele is filled with cerebrospinal fluid which is continuous with the normal cerebrospinal fluid circulation. Richard Avery (talk) 12:32, 8 July 2008 (UTC)

About Hedgehogs

Someone recently asked me if Hedgehogs can climb walls, since I don't know the answer I thought I'd ask here. Apparently one of our neighbours had a hedgehog in their garden recently and they wonder how it got in there, so do you think it's possible for a hedgehog to climb a 6ft (~1.8m) tall wall? Can they climb vertical surfaces at all? --Hibernian (talk) 16:01, 7 July 2008 (UTC)

I doubt they could climb something like that. However, they dig pretty well and wouldn't have any trouble making their way under a wall that isn't actually sunk into the ground, or isn't sunk very deep at all. -- Captain Disdain (talk) 16:14, 7 July 2008 (UTC)

They certainly can. I've found many sources, but the most reliable is Nature Magazine - Letter to the Editor - The Climbing Powers of the Hedgehog. It may only be an anecdote, but Nature would never have published it were there not some element of truth; Nature does NOT like to be proven wrong! -- Skittleys (talk) 17:07, 7 July 2008 (UTC)

No. Echindas climb walls; hedgehogs run really fast. — DanielLC 17:34, 7 July 2008 (UTC)

Hedgehogs are very adept climbers. Climbing up is not a problem. Getting down is. Similar to cats, their claws curl inward. So, when going up, they can dig in and pull themselves up. When going down, their toes curl under and they tumble. Strangely, many species of hedgehogs only have curled claws on the front paws. On the back paws, they have what appears to be more like toenails, not claws. As such, they grow straight outward. I used to think this was limited to the four-toed species, but I've been assured that it is in some species of five-toed hedgehogs as well. For an anecdote, I watched a hedgehog climb a four-foot tall fence made of chicken-wire and hop from the top of it onto the ground. He could have dug under the fence rather easily, but he must have decided that climbing was easier. If you read about pet hedgehogs, you'll see that it is very important that your hedgehog cage has a latched roof or you'll have a hedgehog on the loose by morning (unless you have one of those weird "I'm too cool to climb" hedgehogs). -- kainaw™ 17:41, 7 July 2008 (UTC)

Cats curl inward? --Trovatore (talk) 03:53, 8 July 2008 (UTC)

Oh yes! Got scratched by mine yesterday and boy, they don't half dig in well. — CycloneNimrod  ^Talk? 08:36, 8 July 2008 (UTC)

That would be cats' claws, I think, not cats. --Trovatore (talk) 08:39, 8 July 2008 (UTC)

Cats themselves also curl inwards, sometimes very tightly. A cat curling outwards more than demonstrated in a standard stretch would be alarming. 79.66.67.219 (talk) 05:15, 13 July 2008 (UTC)

Thanks for the info guys. I'll pass that along to them, interesting to know. --Hibernian (talk) 10:01, 8 July 2008 (UTC)

orgasms

what techniques could a hypothetical male use to increase the strength and duration of his orgasms? —Preceding unsigned comment added by Singing Cone (talk • contribs) 16:57, 7 July 2008 (UTC)

hypothetical good diet and exercise. -LambaJan (talk) 17:45, 7 July 2008 (UTC)

And as always, practice makes perfect. Plasticup ^T/C 18:16, 7 July 2008 (UTC)

Maybe it's my dirty mind, but I can't help laughing at Plasticup's username in relation to this question. 79.75.144.130 (talk) 18:33, 7 July 2008 (UTC)

Yeah, it is your dirty mind you bad boy/girl you! -hydnjo talk 02:12, 8 July 2008 (UTC)

I feel a little violated... Plasticup ^T/C 14:22, 8 July 2008 (UTC)

Odd. You should be feeling fulfilled. Matt Deres (talk) 13:41, 10 July 2008 (UTC)

At orgasm I think some discussion is listed. Also, you could find a fetish. Mac Davis (talk) 22:30, 7 July 2008 (UTC)

See Expanded Orgasm. It's about as scientific as you'll get while avoiding answering spam emails. Fribbler (talk) 23:23, 7 July 2008 (UTC)

Be watchful about becoming priapismated! -hydnjo talk 03:47, 8 July 2008 (UTC)

If poisoning occurs (with depilatory wax)

I have some depilatory wax that has instructions saying what to do if poisoning occurs. Now I thought depilatory wax was just a mixture of glucose-like compounds, which sounds harmless. What might be in the wax, and why is it poisonous? 203.221.127.206 (talk) 17:18, 7 July 2008 (UTC)

There should be a list of the ingredients on the packaging. You can then check each one for potential toxicity. It may be that there are no really toxic compounds in it but it could cause a mechanical blockage in the digestive system which would be very dangerous. Exxolon (talk) 18:39, 7 July 2008 (UTC)

A collection of glucose-like compounds would burn when you tried to heat it and wouldn't work as a wax very well. It's more likely a mixture of, well, waxes, which are lipids. Glucose is in a different class of compounds called carbohydrates. --M1ss1ontomars2k4 (talk) 23:01, 7 July 2008 (UTC)

Yeah, that's what I thought too - but check out this [xxtp://www.ehow.com/how_2109787_homemade-depilatory-wax.html homemade stuff] (chg xx to ht - spam filter), definitely glucose-like! In fact, it looks pretty yummy, you could eat it when you were done (guess you'd be spitting out some extras though) :) Franamax (talk) 23:10, 7 July 2008 (UTC)

I think that's because the sugars have polymerized into a long sticky chain. Still not technically a wax, but sticky and semi-solid enough to help with depilation. --M1ss1ontomars2k4 (talk) 00:49, 8 July 2008 (UTC)

Color and Smell changes, Why?

I have moved my question here on the advice on Dismas so it will hopefully received better responses.

-A year or so ago I wanted to know how much cum I could produce in a week, so I used a plasitc bottle every day (sometimes several times a day although the amount would be less each time) to collect it. By the end of the week there was a fair amount, but thats not why I am asking this question. The cum really began to smell rank, like some sort of industrial strength wood glue. It also turned from white to a yellowish color. What caused this, because it was scealed in a bottle and no bacterias could get in? Are there bacterias in the cum when I comes out of me? Does drinking Yakult make this problem worse? ~ ~ ~ ~ —Preceding unsigned comment added by Mud Flood (talk • contribs) 16:39, 7 July 2008 (UTC)

Changes in diet have an effect on sweat, urine, and feces, so it's not out of the question to think that diet would affect semen samples as well. Also, there was a question on one of the ref. desks a week or two ago about the smell of semen. One of the responses said that it contained compounds that are similar to ammonia, so that may be where you're getting the "rank" smell from... Dismas|^(talk) 18:36, 7 July 2008 (UTC)

Ah, thank you. However, this smell changed over time (in a sealed environment). When I cumed to begin with it smelled fine, but over a week smelled like strong wood glue. I don't think this can be attributed to diet unless there are certain compounds in the food which change over time as well. I was more wondering if bacteria or other microorganisms were at work, and if they somehow got to the cum after I ejaculated or if they were present from within me. Mud Flood (talk) 18:42, 7 July 2008 (UTC)

Personally, I don't know and think this would have received better responses on the Science desk instead of Miscellaneous. My own ideas would be that either A) chemicals in the semen are breaking down due to time, exposure to light, exposure to air, etc. B) something is reacting with the plastic container, or C) the container wasn't clean enough to begin with and something is, again, reacting. One more thing I just thought of... pre-ejaculate contains chemicals to help the sperm survive through the urethra. It basically keeps the chemicals in urine from killing the sperm. There could be something going on with that as well. Dismas|^(talk) 18:59, 7 July 2008 (UTC)

Surely something as simple as decomposition would account for the change? Organic material that isn't refrigerated tends to go bad, particularly if it isn't refrigerated. Mere contact with air and light cause things like this to degrade. Also, it's hardly a sealed jar if you keep opening it up several times a day, especially in a non-sterile environment. I mean, did you thoroughly wash your hands and your penis every time before embarking on this grand scientific experiment, for example? Did you wear rubber gloves? Are you sure the jar was sterile to begin with? Did you somehow ensure that nothing contaminated the sample before it ended up in the jar? (And bear in mind that just touching it a little with a fingertip is inevitably going to slap a bunch of bacteria in it, which, after a week of growing, multiplying and going to work, are going to wreak merry hell with the sample -- and, in fact, the same pretty much applies to the tip of your penis, so getting a completely uncontaminated sample is going to be pretty much impossible.) There's a reason why they don't store the sperm samples in labs or sperm banks in jars on countertops.

Also: Ew. Not to dis the curiosity or the act in itself (hey, if this kind of thing works for you, it's fine by me), but a jar full of week-old sperm doesn't strike me great mood-setter. If you want to know how much of it you produce, you could just measure it by emission and keep a log or something, just so you don't have to live with that, uh, wood glue smell. Let me tell you, the chances of that jar's contents ever getting any better the longer you keep it around aren't too great... -- Captain Disdain (talk) 21:53, 7 July 2008 (UTC)

I'd say its just decomposition of the compounds. Here's a question: Did you get the idea from 4chan, or did you create the idea on 4chan? :) Mac Davis (talk) 17:20, 8 July 2008 (UTC)

Personally, I'd start worrying about fluoride in your drinking water affecting Our Precious (bodily) Essence.

Atlant (talk) 17:28, 8 July 2008 (UTC)

Just in case no one else mentions it, I feel it my duty to recount one of my favorite jokes:

A young male student was caught pleasuring himself in his bedroom by his housemaster.

Housemaster; Perkins, you should not be doing that! You should save it for when you are married.

Perkins (pointing to a shelf lined with full liter jars above his bed) I am Sir, look! —Preceding unsigned comment added by 79.76.144.199 (talk) 00:17, 9 July 2008 (UTC)

Measuring Power

What is the easiest/cheapest way to measure a current of ~1 pW? Orders of magnitude (power) mentions an FM receiver as being able to have a precision as low as 10 fW. Could I build/buy a similar receiver, but not necessarily as precise? Or is there an easier way? Thanks, *Max* (talk) 19:48, 7 July 2008 (UTC).

At the risk of being pedantic, current is measured in Amps, while power is measured in Watts. It would probably help to be more detailed in what you want to do. Dragons flight (talk) 21:33, 7 July 2008 (UTC)

I meant that the power is in the form of an electric current. I want to put something in the circuit that measures the power, which is about 50 pW with a precision of <1 pW. *Max* (talk) 21:46, 7 July 2008 (UTC).

In general, people don't usually measure power, instead they measure current and voltage and derive the power involved. Which is why it would be helpful to know more about the circuit. Also, is there a time resolution involved? It's a lot easier to say that the average power over many minutes is 50 pW than to measure 50 pW with, for example, millisecond precision. Dragons flight (talk) 21:59, 7 July 2008 (UTC)

That's not exactly true. A bolometer directly measures the electric or optical power delivered through a transmission line by dissipating that power in an appropriate load impedance and measuring the heating effect the incoming power has upon the load. 50 pW is a pretty small amount of heating power, though, so you need a pretty fancy (e.g. cryogenic) bolometer to measure that sort of power level.

Atlant (talk) 17:21, 8 July 2008 (UTC)

I think you have the wrong term. Bolometers are primarily used to measure the power contained in electromagnetic radiation. I can't imagine any circumstance where you would hook one up to a power line directly and the article doesn't mention such uses. Dragons flight (talk) 17:28, 8 July 2008 (UTC)

The article is incomplete. See this PDF from Agilent Technologies [3]

Atlant (talk) 17:45, 8 July 2008 (UTC)

I don't know the current/voltage, just the power. Both are small, but I don't know how small. I do not need precise measurements over short periods of time, I just need to know whether it is operating at full power or not. *Max* (talk) 22:54, 7 July 2008 (UTC).

If you really want to measure power... measure the temperature inside a thermos, put the component in and seal the thermos as well as you can, leave it in there for a while and measure the new temperature.

Seriously though, what are you actually measuring? Power dissipated across something? More information is needed. --antilived^{T | C | G} 23:36, 7 July 2008 (UTC)

Max, I think you might need to define the question a little better. Are you talking about DC current, long-wave AC, RF AC? Antilived's first part won't help - putting a 50pW radiator inside a thermos will take an awful long time to heat your coffee. But they are right that we need to know more about the problem. If that steps across some patent you are trying to get, it will make it much more difficult to help out. Franamax (talk) 01:36, 8 July 2008 (UTC)

Radio antennas pick up radio frequency electromagnetic radiation. The voltage picked up by the antenna might be microvolts. The impedance could allow you to calculate the current and the power. Or you could work backwards, using the gain of the radio frequency amplification stages and the output voltage to calculate the input voltage, which, combined with the impedance, would give you the input wattage to an AM or FM or TV receiver. Is this what you were talking about? Edison (talk) 03:11, 8 July 2008 (UTC)

Yeah, I couldn't believe that 10fW spec for a receiver, so I found some specs and worked backward. Whadda'ya know - it's on the order of femtowatts, who would have thought en:wiki was a reliable source! And yes, frequency will be very important if the intent is to measure and calculate power (VxA) flowing through something, OTOH if the aim is to measure power dissipation, then wouldn't a sensitive calorimter be more appropriate? (Especially at these low power levels where the measuring device could appreciably distort the measurement? Just asking! )Franamax (talk) 03:28, 8 July 2008 (UTC)

Pet Budgerigars and mirrors

Does anyone know what the latest thinking is WRT to allowing a singly-kept, caged Budgerigar access to a mirror? Is it generally considered to be (by experts) a good or a bad thing now, in terms of the effects upon the bird's psychology? --Kurt Shaped Box (talk) 21:36, 7 July 2008 (UTC)

I'm no expert, but personal experience with different birds over the years indicate strongly that a mirror keeps the bird company, and combats boredom. Budgies are sociable birds. If you don't want to put in a mirror, I'd say get your bird a partner to share the cage. ~Amatulić (talk) 23:47, 7 July 2008 (UTC)

The problem seems to be (there is always debate about this on bird forums) that a single budgie can become too attached to his/her reflection and go all obsessive-compulsive - or can become frustrated and very aggressive due to the reflection refusing to 'answer back'. My inside budgie doesn't have a mirror - but he gets lots of playtime with me/general outside the cage playtime and seems relatively sane. --Kurt Shaped Box (talk) 00:09, 8 July 2008 (UTC)

I take it budgies aren't smart enough to figure out it's their own reflection ? StuRat (talk) 03:02, 8 July 2008 (UTC)

Our article on self-awareness claims that the existing evidence so far suggests that only bottlenose dolphins, apes, and elephants are self-aware (and mirrors often factor into those experiments). Meanwhile, our sun conure had a mirror for a while and never interacted with it one way or another. And "the parrot in the mirror" is a running gag in the Monty comic strip.

Atlant (talk) 17:14, 8 July 2008 (UTC)

From the mirror test article and other Internet sources, it seems that very few animals can pass the test. Even humans younger than 18 months cannot recognize themselves in a mirror. --Bowlhover (talk) 17:34, 8 July 2008 (UTC)

My friend owns an African Grey, which I have babysat for him on occasion. He has a mirror in his cage, which he doesn't seem to be interested in at all. I don't know whether he actually recognizes his own reflection as him or not - but he obviously understands that it's not really another bird. It's not scary, it's not something that he can pick up and throw, it's too smooth to scratch himself on and it's doesn't have a chewable texture, so it appears to be largely irrelevant to him. --Kurt Shaped Box (talk) 19:03, 8 July 2008 (UTC)

I've never seen a budgie that understands the concept of 'mirror'. Put one in the cage and the bird will spend all it's free time pressed up against it, beak-tapping and cooing. Sometimes the budgie will even try to feed or mate with its own reflection. It's a similar deal with cockatiels, as far as I know. I can understand why some may consider this to be unhealthy. --Kurt Shaped Box (talk) 19:08, 8 July 2008 (UTC)

If a budgie isn't psycologically capable of recognizing a mirror for what it is, why would he be capable of any psychological harm from having a mirror? Seems to me that providing a source of entertainment and company is beneficial, not harmful. When I had a budgie, he kissed and fought his mirror, but played with me when I was around, flying to my shoulder and nibbling my ear. The mirror kept him occupied at other times.

Personally, I think the folks arguing about potential harm are anthropomorphizing their pets too much. ~Amatulić (talk) 14:59, 9 July 2008 (UTC)

I think the problem is that the mirrors will reflect the bird's own personalities back at them. An affectionate bird may appreciate the mirror, as he thinks that another affectionate bird has been placed in the cage, while an aggressive bird might be stressed out, thinking another aggressive bird is next to him and he must always keep one eye open. StuRat (talk) 04:33, 10 July 2008 (UTC)

Airplane engines "opening" up

I've noticed on several flights over the last year that upon landing, a metal sheath on the engine seems to slide backwards, revealing what appears to be a grill. The planes were some Boeing model with Rolls Royce engines. Anyone know what the engines were doing? 151.152.101.44 (talk) 22:36, 7 July 2008 (UTC)

Those reverse thrust to slow the plane down. --M1ss1ontomars2k4 (talk) 22:47, 7 July 2008 (UTC)

See thrust reversal. They are used when the plane is still going at a high speed and brakes aren't very effective yet. --antilived^{T | C | G} 23:50, 7 July 2008 (UTC)

This is correct, and by the way, reverse thrust is also available on some propeller planes by reversing the pitch of the propeller (i.e. rotating each blade around its long axis so that it angles the other way). But it should be added that reverse thrust doesn't contribute all that much to a plane's ability to stop; it's the brakes that absorb most of the kinetic energy. It has to be that way, really; a plane has to be able to land safely if the engines stop running, and in that case reverse thrust would not be available. --Anonymous, 06:57 UTC, July 8, 2008.

Strips of metal hanging in unfinished buildings

In two seperate buildings under construction, hanging from the (temporary?) metal floors are dozens or hundreds of shiny strips of metal. Does anyone know what are these for? 151.152.101.44 (talk) 22:36, 7 July 2008 (UTC)

Hmm, I've worked in the construction industry in Ireland, and those strips were the remnants of metal bands used to contain pallets of blocks or bricks. They get everywhere! Fribbler (talk) 23:45, 7 July 2008 (UTC)

Could be straps that will be used to hang stuff below those floors (hung-ceilings in the level below, etc)? DMacks (talk) 02:23, 8 July 2008 (UTC)

Organic chemistry reaction

Hello; what's the expected product of this reaction? My guess was this, but something tells me I should have considered turning the hemiacetal back into a dialdehyde first. --M1ss1ontomars2k4 (talk) 22:57, 7 July 2008 (UTC)

My guess would be conversion to the 4hydroxy butaldehyde first, followed by condensation to give a hydrazone, maybe something else happens after that?87.102.86.73 (talk) 02:05, 8 July 2008 (UTC)

Note: protonation at the hydroxyl allows the condensation to occur without making the aldehyde first.

I've no idea if the resultant compound undergoes further reactions eg protonation at hydroxyl, followed by electrophilic aromatic substitution..87.102.86.73 (talk) 06:19, 8 July 2008 (UTC)

Under normal conditions the hydrazone of 4hydroxy butyraldehyde is the final product. --Stone (talk) 06:26, 8 July 2008 (UTC)

Yeah, that turns out to be correct. Thanks! --M1ss1ontomars2k4 (talk) 05:11, 9 July 2008 (UTC)