Wikipedia:Reference desk/Archives/Science/2006 August 19

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bee B-gone

I have bees in the top of my house. My exterminator is not successful in killing them. I have sprayed them with cheep store bought spray to no avail. I live in Dallas Tx. I dont know what kind of bees they are. I am too old and scaired of them to get close to them on a ladder. I dont want to use my bug man again. What can I do? Thanks 24.0.47.184 03:11, 19 August 2006 (UTC)[reply]

WHATEVER YOU DO, DO NOT RUN INTO THEM SCREAMING. — [Mac Davis] (talk)

You could import some Bee-eaters — [Mac Davis] (talk)

Telsa coils? — [Mac Davis] (talk)

Okay, I'm not helping. — [Mac Davis] (talk)

Perhaps try another, different exterminator? Are you sure they are bees and not hornets or yellowjackets? If they are either of the latter then I definitely do not recommend trying it yourself if you have any doubts because they can be very aggressive (bees are not very aggressive in general, but hornets/yellowjackets are and are very territorial, and unlike a bee can sting many times). --Fastfission 04:34, 19 August 2006 (UTC)[reply]

I recommend poison. However, depending on the type of bee, wasp, or hornet, a different poison may be indicated. If you can manage to kill one, look at it up close and compare with pics online or in a book to identify the type. A good exterminator should have identified the species, too, but it sounds like you had a lousy exterminator (perhaps literally), so he may not have done that, either. Once you've identified the species, go online and do a Google search for the best poison. Ideally, they should take it back to the hive and kill the queen, too. StuRat 05:49, 19 August 2006 (UTC)[reply]

Dont bee keepers use smoke to make the bees dopey when they are moving the hive--Light current 05:58, 19 August 2006 (UTC)[reply]

You could try smoking Hamlet cigars. (2B or not 2B TITQ)--Light current 06:10, 19 August 2006 (UTC)[reply]

Smoke makes them leave without becoming angry, since they don't blame anyone for a fire. But they would just return once the smoke clears. You need them dead. StuRat 07:50, 19 August 2006 (UTC)[reply]

Call your local fire department. Sometimes, they'll come to spray them with soapy water. At least, that's what they did one time in my house. Tito xd^(?!?) 07:53, 19 August 2006 (UTC)[reply]

What? Hes not trying to give them a bath!--Light current 07:57, 19 August 2006 (UTC)[reply]

IIRC, it destroys the beehive. Tito xd^(?!?) 08:10, 19 August 2006 (UTC)[reply]

surely its better to get a proper bee keeper to move the bees to a new hive! Bees are very useful creatures you know!--Light current 08:18, 19 August 2006 (UTC)[reply]

Yeah that it! Found on bee keeping page. Smoke em out but make sure you have a new hive readyand waiting at the bottom of the garden. THen when theyre all out, remove the old hive and destroy it.(after removing any XS honey)--Light current 09:53, 19 August 2006 (UTC)[reply]

Hive + lighter fluid + matches = no more bees --Kurt Shaped Box 10:48, 19 August 2006 (UTC)[reply]

...or house. --Fastfission 12:40, 19 August 2006 (UTC)[reply]

There is a nice recipe for napalm here. Shotgun shells can also destroy the hive. Hydrofluoric acid too. We could write a book! "99 ways to kill bees." — [Mac Davis] (talk)

Small, locally-generated EMP? I hear that putting one of those plastic Elizabethan collars around your neck to act as a reflector, then getting down on all fours, as close to the bees as possible and blowing a whistle *really* hard works. --Kurt Shaped Box 05:31, 20 August 2006 (UTC)[reply]

What's wrong with having bees in the roof? --liquidGhoul 14:24, 19 August 2006 (UTC)[reply]

BZZZZZZZZZZZ Yes I suppose theyll leave eventually and swarm to another hive--Light current 14:35, 19 August 2006 (UTC)[reply]

I usually get them out of my house (attic) by creating smoke using charcoal tablet and olibanum then throw away the nest. They usually dont come back. helohe (talk) 15:50, 19 August 2006 (UTC)[reply]

The fact that you have devised a 'usual' method of getting rid of them rather throws doubt on your latter assertion, no? :-) --Yummifruitbat 01:35, 20 August 2006 (UTC)[reply]

Sheep and goat breeding

Hi

Does anyone know if sheep and goats have been bred together in the past to give the modern breeds of sheep and goat? I know that the sheep-goat hybrid page pretty much says it's impossible, but it'd be great if they have been.

Cheers

Aaadddaaammm 05:32, 19 August 2006 (UTC)[reply]

Um no. but modern sheep are a mix of many breeds of sheep, though goats aren't as mixed. Still, they don't generally hybridise, they have different numbers of chromosomes. pschemp | talk 06:12, 19 August 2006 (UTC)[reply]

True, but consider the strange case of "Bemya" the randy rapist sheep-goat. Rockpocket 06:39, 19 August 2006 (UTC)[reply]

It aint randy no more -- apparently--Light current 06:57, 19 August 2006 (UTC)[reply]

Sea water turned Sweet

Hi,

This is regarding a Phenomenon which occurred yesterday(18/08/2006) around 10 p.m. in one of the areas in Mumbai in India. One of the guys who was having a bath in the sea, accidentally drank the seawater and to his surprise it tasted sweet. And the news spread like anything and in hours thousands of people gathered at this place to collect the sweet sea water. People started drinking the water thinking it as a holy thing, forgetting the fact that it is highly contaminated by domestic sewage and industrial effluents. They all think without exception that it was a miracle that would cure them of every known ill on the planet.

So My question is why this happened? Were there any incidents similar to this occurred ever before in any part of the world? what would be the scientific reason behind this?

If anybody can answer these questions it will be appreciated.

Thank You

When you say sweet, do you mean not salty? If so, is it possible there had been a big outflow of fresh water into the sea at that point after heavy rains. Which part of Mumbai did this happen in. Is Mumbai near the mouth of a river?--Light current 06:48, 19 August 2006 (UTC)[reply]

The're now confirming that it could be due to the heavy rains. And it is at the mouth of the Mithi River =Nichalp «Talk»= 17:14, 19 August 2006 (UTC)[reply]

I'm from Mumbai and the incident happened near the dargah of Makhdoom Ali Mahimi in Mahim. People have been attributing it to miraculous powers but from my knowledge of the geology of Mumbai, the city is known to have many underground springs just metres away from the sea shore. Prominent examples are the Bhika Behram Well at Churchgate, the underground springs that used to feed the now-filled up Dhobitalao (the springs were rediscovered when the subway construction started last May) [I have a pic of them], Banganga Tank (50 m from the shoreline), and an underground stream that is used to water Priyadarshini Park. I'm discounting water sources in the suburbs as there are plenty of lakes and rivers. So I don't think it's a miracle. Regards, =Nichalp «Talk»= 08:38, 19 August 2006 (UTC)[reply]

It would be interesting to see this scientifically proven, but I doubt it. Didn't terrorists bomb a sugar company yesterday? — [Mac Davis] (talk)

Or was it just the sugar company washing its sewers ? -- DLL ^{.. T} 18:14, 19 August 2006 (UTC)[reply]

It might have been a large amount of ethylene glycol, the chief component in antifreeze, or a similar chemical washed out from the sewers. It tastes sweet, but is also quite toxic. If so, I only hope it was diluted enough so that nobody dies. StuRat 18:48, 19 August 2006 (UTC)[reply]

Perhaps some out-of-control diabetics were bathing there and peed in the water.Their urine would have been high in sugar. Edison 03:35, 20 August 2006 (UTC)[reply]

No glare using UV

Why is it that when illuminating paper thro a plastic sleeve by UV, you get no glare, but you get glare from the sleeve when using visible light?--Light current 07:37, 19 August 2006 (UTC)[reply]

You can see the visible light that reflects off the plastic, but you can't see the UV light that reflects off because it's invisible UV. The only reason you can see the paper under UV is because the paper fluoresces, which means it absorbs UV and emits visible light. The plastic doesn't fluoresce because it's transparent and doesn't absorb the light. —Keenan Pepper 09:59, 19 August 2006 (UTC)[reply]

Of course! Why didnt I think of that? THanks alot! Any way it seems a good method of illuminating music to read without illuminating anything else! Not sure of any hazards tho!--Light current 10:02, 19 August 2006 (UTC)[reply]

I hope you're not thinking of taking one right from a lab to use as reading lamp, probably not such a good idea, unless you mean one of these cheap novelty bulbs, they're pretty much harmless--71.247.125.144 13:29, 19 August 2006 (UTC)[reply]

Dunno havent researched it yet. But a musician friend if mine has made one. It uses a bulb shaped like a normal incandescent. Not sure where he got it but its not a germicidal one-- its probably a longer wavelength 'blacklight' bulb--Light current 14:33, 19 August 2006 (UTC)[reply]

A minor note of caution—while there isn't much evidence (at this time) to support a link between long wave ultraviolet (from the 'black' lights) and skin cancer or cataracts, this type of UV is definitely energetic enough to damage collagen in the skin. This sort of damage is associated with premature aging and the formation of wrinkles. I'm not sure how much of a dose you'd get from one of those little lights, but it's something to bear in mind if you intend to sit in front of one for hours at a time. TenOfAllTrades(talk) 15:51, 19 August 2006 (UTC)[reply]

THis musician friend is about 75, so I dont think itll do him much harm. I.. OTOH, am much younger (and look it)--Light current 16:16, 19 August 2006 (UTC)[reply]

Where did the brain of the zygote/fetus come from?

Since we came into existence when the sperm hits the egg, it becomes a zygote! So the zygote developes into a fetus. Someone could say "I was a sperm once." Or, "I was an egg once," when someone else could say "No, you're really when the sperm and the egg hit to become a zygote."

Well, I really consider myself to be my brain, so I'm curios: Did the sperm have 1 hemisphere of the brain and the egg the other hemisphere, and the 2 brain hemispheres merged to become our current brain when the sperm hit the egg? (I'm thinking not, so I'm assuming maybe the brain, or what became of the brain, is 100% from either the sperm or the egg)... But which one? User:NealIRC 19 August 9:17 (UT)

Half chromosomes from sperm, half chromosomes from egg I think. Chromosomes are only the instructions on how to build a baby so all your brain is due to both parents I would say.--Light current 09:13, 19 August 2006 (UTC)[reply]

Light current is right; an initial cell is formed from the fusion of the sperm and the egg. That cell divides into many and differentiates into different structures, including the embryo and the placenta. The ~~placenta~~ embryo also divides into many structures, one of which becomes the brain and spinal cord. You may find Fetal development an interesting article. If you're really keen, look at Neurulation, but that's rather a technical article.-gadfium 09:29, 19 August 2006 (UTC)[reply]

No, the brain and spinal cord do not derive from the placenta. Just like every other component of the embryo, they derive from the inner cell mass. The placenta derives from the trophoblast. --David Iberri (talk) 01:04, 23 August 2006 (UTC)[reply]

Oops, typo on my part. I meant the embryo, and I was trying to simplify. I've adjusted it above, since it's such a grievous error. Amazing no one picked up on it until now.-gadfium 04:16, 23 August 2006 (UTC)[reply]

My god! My guess was right! I must take up biology (or is it embryology)--Light current 09:38, 19 August 2006 (UTC)[reply]

Well, it's a pretty straightforward conclusion, other than the details on how the development takes place. The sperm and the egg, being single-celled, have no brains whatsoever, and not even something that resembles a brain. Neither does the initial embryo. The brain develops much later. The instructions on how to build the brain, though, naturally come from both halves of the genetic code, as do most other things. Black Carrot 14:52, 19 August 2006 (UTC)[reply]

For most, the right hemisphere is feminine and imaginative, the left one being masculine and logical. But this has not necessarily a link with your parents' capacities :) -- DLL ^{.. T} 18:12, 19 August 2006 (UTC)[reply]

So if Im left handed and thats controlled by the right brain, does that make me a woman?--Light current 18:48, 19 August 2006 (UTC)[reply]

If, however, you are interested in where the molecules to construct the brain came from, those were first eaten by the mother, absorbed into her bloodstream, then delivered, via the umbilical cord, to the embryo/fetus. StuRat 18:42, 19 August 2006 (UTC)[reply]

Symbols on electrical appliances

Some electrical appliances have symbols on them, like an inverted triangle with an F inside, or a circle with an S, N, or D, and other symbols. I looked for a site that explains what these symbols mean but surprisingly I couldn't find any. Maybe you can help. S Sepp 13:31, 19 August 2006 (UTC)[reply]

The circle with the N inside means that it has been authorized for use in Norway. I would guess that the S and D work the same way for Sweden and Denmark, respectively. Have'nt seen the F in an inverted triangle. -N·Blue^talk 14:16, 19 August 2006 (UTC)[reply]

Agree. I think theyre all European underwriters approvals (like UL in US)--Light current 15:00, 19 August 2006 (UTC)[reply]

Are the signs any thing like this? [1]

Yes! That's what they look like. So they are certification marks. Thank you. S Sepp 19:34, 19 August 2006 (UTC)[reply]

Another Wikipedia sucess!--Light current 19:36, 19 August 2006 (UTC)[reply]

Perhaps the inverted triangle with an F inside means it's authorized for use by male homosexuals ? :-) StuRat 18:34, 19 August 2006 (UTC)[reply]

I dont get that! Are you referring to the pink triangle the Nazis used to denote homosexuals? A bit tastless methinks!--Light current 18:40, 19 August 2006 (UTC)[reply]

I specialize in tastelessness. :-) StuRat 23:35, 19 August 2006 (UTC)[reply]

I noticed. But why the F?--Light current 01:03, 20 August 2006 (UTC)[reply]

You really can't figure that one out ? It's even too tasteless to mention here. StuRat 02:58, 20 August 2006 (UTC)[reply]

Is it the same word as the slang for cigarette in the UK?--Light current 03:08, 20 August 2006 (UTC)[reply]

LOL, there ya go. StuRat 15:44, 20 August 2006 (UTC)[reply]

Which Glue in a Microwave-Convection Oven?

On cleaning my combination microwave-convection oven, I noticed that one of it's internal seals is cracked. The seal is an 120x100x0.3 mm mica plate covering the site of entry of the microwaves into the oven cavity, sited in the top wall (ceiling?) of the oven. Its function seems to be to prevent vapours from the oven from reaching the magnetron workings. The crack was probably caused during cleaning, and runs about halfway through the plate from one side to the other. The oven itself is a standard 900W microwave, and it has a convection heating element and fan situated in one of the side oven walls, with halogen grilling tubes in the ceiling. The convection temperature can be set up to 240°C. So the mica seal would be exposed to microwave energy coming through it into the oven, as well as to hot air, water vapour and hot oil droplets from the convection heating and the food. It would not be directly exposed to the infrared from the halogen tubes. My question is, can anyone suggest a bonding material which would keep the crack from spreading? It would have to be microwave-safe once cured, able to tolerate pretty hot, humid and oily conditions, and obviously not highly toxic. It need only last for as long as it takes to get a replacement seal, a week or two. Any ideas? --Seejyb 15:04, 19 August 2006 (UTC)[reply]

Don't use cyanoacrylate or anything polyvinyl acetate. — [Mac Davis] (talk)

What about a 2 part epoxy (like Araldite). I dont know the upper temp limit tho!--Light current 16:42, 19 August 2006 (UTC)[reply]

I wouldn't recommend trying to fix it, especially if you are getting a replacement in the near future. Is there a functional reason that you can't operate the device without this sheild? If so, perhaps removing it and using a temporary shield of waxed cardboard (if you are worried about steam and spattering on the magnetron housing) would work.Tuckerekcut 17:34, 19 August 2006 (UTC)[reply]

I wouldn't risk using it until you get the replacement seal. Two weeks of stove-top food, take out, and sandwiches won't hurt you, but leaking microwaves could. StuRat 18:32, 19 August 2006 (UTC)[reply]

The micro waves aint gonna leak- its the gases thatll leak to the magnetron--Light current 18:45, 19 August 2006 (UTC)[reply]

What are the microwave properties of waxed carboard? Probably very lossy! I think it could could combust. I wouldnt do that.--Light current 18:43, 19 August 2006 (UTC)[reply]

Inexpensive microwave ovens often use waxed cardboard on the superior wall, perhaps the manufacturers don't think you will clean the ceiling very often. I had a sharp brand microwave in my dormitory with one, and one of the student lounges at my school has a panasonic microwave with a waxed-cardboard ceiling. If you are concerned about cardboard in the microwave, consider that most crisping sleeves and pizza boxes (on the brands that suggest you use the packaging to elevate a cooking pizza) are made of cardboard.Tuckerekcut 19:45, 19 August 2006 (UTC)[reply]

Waxed cardboard ? What, weren't any old gum wrappers available ? StuRat 02:51, 20 August 2006 (UTC)[reply]

Waxed cardboard with a reflective metallic surface maybe. But what is required is something thats transparent to micro waves and wont ignite here isnt it? So I reiterate waxed cardboard is not a good idea (any way didnt you read the question? Halogen grilling tubes in the ceiling. The convection temperature can be set up to 240°C.--Light current 19:55, 19 August 2006 (UTC)[reply]

Hey thanks,I wasn't expecting so many replies. I'd have "instinctively" used cyanoacrylate, because the break is clean and sharp, and it "looks like the kind of job" that c-a would do nicely. I should say I was going to use it but decided to ask first! So now I won't. As to the Araldite: the 2-part epoxies soften -- I once lovingly made an epoxy turntable for my mom, when her glass turntable broke (and the replacement turntable was found to cost almost as much as a new oven -- I wonder what my seal is going to cost!). It was cast in the lid of a cake tin, and signed "from your son" on the back. After being test-microwaved for a while, the thing softened and sagged, and was palced underneath a potplant on her patio. In her case we found a ceramic pizza plate that fitted well, moulded the drive fittings from pottery clay, and it is still working. The cardboard solution bothers me in as far as using the convection oven at say 200°C, and then microwaving the stuff - I'm not sure at what stage it could decide to ignite. While pondering the issue, I have decided to try drilling small holes thru the mica, and fixing the sides together with 3 ordinary paper staples, inserted and bent by tweezers. This should prevent progression of the crack (he says optimistically!), the small mass of steel shouldn't obstruct the microwaves much, rust over such a short time shouldn't be a problem, and I'd be keeping the inner workings clean. If I manage to break the mica, I'll cut and grind a piece of glass to jam inside the duct that carries the microwaves, and hope it stays put. And if that doesn't work I'll put in cardboard and unplug the wires going to the convection and radiant heating elements (I know about working inside: "No 1: first discharge the capacitor"), using microwaves only. I'd be watching the cardboard closely, though. I'll let you know what happens. But if someone does know of a safe bonding substance, please post. (I've just thought: what about a high heat silicone sealing paste, or the stuff they use to make car engine gaskets from, or the stuff for sealing exhaust pipes? I have them all in my garage, and it need not be a strong bond, since the mica plate carries no stress - are these things toxic?)--Seejyb 20:56, 19 August 2006 (UTC)[reply]

Id be careful about using staples. THey are conductors you know! You may get arcing I think you really need some ceramic based gunk. Maybe grouting compound for tiles. Do you have any of that?--Light current 23:01, 19 August 2006 (UTC)[reply]

Ah yes, little corona sparks all over - I was thinking of accidentally making a Faraday cage if I used steel, but forgot about the arcing. I've checked in the oven now with the room lights off, and yes indeed, they do spark a bit. The mica is not much affected, fortunately. So I'll take my staples out and seal the crack with pottery clay. The clay I have should do it - the cups and plates I made turned out to be quite microwave safe. Thanks. --Seejyb 02:55, 20 August 2006 (UTC)[reply]

Ahh you didnt say you had clay. THat sounds like it might heat up with the water in it. THat may tend to either fire the clay or set fire to the oven! Who can tell?--Light current 03:14, 20 August 2006 (UTC)[reply]

Airplane's low oxygen

I was just watching on "Discoveries this Week", on The Science Channel flight attendants training. I wondered how long could somebody like Lance Armstrong or Greg LeMond with a VO₂ max of 80-95 last in normal conditions of a plane losing pressure or oxygen concentration or whatever it was. Could they just sit there? If not, how long would it take? — [Mac Davis] (talk)

If they were in a near vacuum, they might end up exploding. —D a niel (‽) 16:01, 19 August 2006 (UTC)[reply]

Not really any more than diving two or three meters causes people to implode (also a 1 ATM pressure difference). See explosive decompression and the external link at the bottom of that article. Also on the subject: cabin pressurization, altitude sickness. How a person reacts depends on what he tries to do, what the pressure is (i.e. altitude), does he have time to acclimatise, ... Weregerbil 16:40, 19 August 2006 (UTC)[reply]

I dont think thats quite right Weregerbil. I think the human body can stand more inward force that outward because the internal blood and fluid pressures can balance inward forces more easily. If you put a sucker on any part of your body ( 8-)) the blood pressure will tend to forse the tissues out and maybe rupture some blood vessels. Didnt yoo see that film Total Recall (Arnie Schwarzeneggar) and the bit where he was ejected onto the zero pressure surface of Mars. Nasty! --Light current 16:49, 19 August 2006 (UTC)[reply]

Yeah, I saw Total Recall. Hollywood is unique in that it is the only place in the universe where people explode in vacuum. See explosive decompression and the external link at the bottom of that article. The external article in particular lists real world cases of people having been exposed to hard vacuum. Weregerbil 17:34, 19 August 2006 (UTC)[reply]

That movie completely fell apart at the end. Terraforming would likely take thousands of years to complete, but our Martian friends apparently spent the extra money to do it in 30 seconds flat, LOL. Then they just "forgot" to turn it on ? Apparently 4 year olds have been running Hollywood for quite some time now. StuRat 20:58, 19 August 2006 (UTC)[reply]

Hey I wouldnt recommend it : I didnt say they would explode. Arnie didnt explode but he didnt look to well with bulging eyes, veins etc.

During this time, water vapor will form rapidly in the soft tissues and somewhat less rapidly in the venous blood. This evolution of water vapor will cause marked swelling of the body to perhaps twice its normal volume unless it is restrained by a pressure suit. (It has been demonstrated that a properly fitted elastic garment can entirely prevent ebullism at pressures as low as 15 mm Hg absolute [Webb, 1969, 1970].) Heart rate may rise initially, but will fall rapidly thereafter. Arterial blood pressure will also fall over a period of 30 to 60 seconds, while venous pressure rises due to distention of the venous system by gas and vapor. Venous pressure will meet or exceed arterial pressure within one minute. There will be virtually no effective circulation of blood. After an initial rush of gas from the lungs during decompression, gas and water vapor will continue to flow outward through the airways. This continual evaporation of water will cool the mouth and nose to near-freezing temperatures; the remainder of the body will also become cooled, but more slowly.

my bolding

From that ref of yours.--Light current 17:51, 19 August 2006 (UTC)[reply]

Ahh, but once in a while, reality prevails even in Hollywood. Remember the famous jump through space sans helmet into the airlock in 2001:A Space Odyssey? alteripse 19:55, 19 August 2006 (UTC)[reply]

Please dont Q jump!. Yes apparently that brief excursion would actually be possible.--Light current 19:58, 19 August 2006 (UTC) Sorry to burst your bubble guys, but none of that is true. Well, that's what NASA says. [2] — [Mac Davis] (talk)[reply]

We must go with NASA version. THey are the ultimate authority on this. case closed

--Light current 00:51, 20 August 2006 (UTC)[reply]

The article on The Armstrong Limit (not named after Lance) has an interesting NASA report on some chap that was accidently exposed to a near vaccum. Rockpocket 01:42, 20 August 2006 (UTC)[reply]

Complete replacement of cells

Hi all! I've tried as hard as I can to look for a Wikipedia article which talks about the time it takes for different types of organs and tissues to replace their cells completely with new ones (processes which I'm sure you've heard about, since people love saying that 'we all become completely new persons every X months' because of this...-.-), but I haven't been able to find anything remotely like that! (I don't know if this even has a name of some sort...)

I hope I'm clear about what I'm talking about: as far as I know, it takes a certain amount of time for, say, bones to replace all its old cells with new ones, and of course there are different time periods for different tissues to 'become completely new', from hours to months! (Not ALL tissues do this of course, but you'd be impressed by how many actually do!) I hope this subject isn't just spread around the articles for each organ or cell type, because this'd make for a pretty good and informative article all by itself!

I'd be grateful if you could point me to an article which talks about this, or simply check if there is indeed no article about this, so the right thing is done and it is written. Thanks in advance! Kreachure 17:10, 19 August 2006 (UTC)[reply]

Our Adult stem cell article may be a good place to start looking. Rockpocket 19:42, 19 August 2006 (UTC)[reply]

It doesn't look like there is a specific article on the subject, probably because its pretty difficult to know (in humans at least) how long it takes. However, it does say that the Olfactory receptor neurons of the nose are entirely replaced every 40 days or so in humans. Rockpocket 19:49, 19 August 2006 (UTC)[reply]

Time measurement

I was working on an article related to time measurement (Indian Standard Time) before the advent of the atomic clock. The best information I could find on wikipedia is the article Tempometer. My question is: Before the atomic clock came into existence, how did people accurately measure the precise time? (I'm interested in the era between 1800 to 1955). Regards, =Nichalp «Talk»= 17:25, 19 August 2006 (UTC)[reply]

Have you tried chronometer yet?--Light current 17:32, 19 August 2006 (UTC)[reply]

Yes I did, and the best mention there was the H4 chronometer. I'm specifically looking for an official device (if any) that the governments used to keep the time. =Nichalp «Talk»= 17:43, 19 August 2006 (UTC)[reply]

Well before atomic clocks, quartz clocks were used Im sure. Have you tried that?--Light current 19:34, 19 August 2006 (UTC)[reply]

One place you can research: [3]. And then you can tell us all about the Shepherd master clock of course :-) Weregerbil 18:55, 19 August 2006 (UTC)[reply]

This link shows a picture of the "8-day wall regulator" by Dent, at the Royal Greenwich Observatory, that was used for timing the six-pip time signal BBC radio has been broadcasting since 1924. --Lambiam ^Talk 19:49, 19 August 2006 (UTC)[reply]

By the way, Tempometer is nonsense, and I'm going to AfD it when I get the chance. Melchoir 22:24, 19 August 2006 (UTC)[reply]

The pages on timekeeping at the US National Institute of Standards and Technology are well done, not too technically detailed, and a good place to find the search item names for your favourite search engine. The British National Maritime Museum is another remarkable site, with photographs of the beautful timepieces that were made in the past. The British specifically would have made a large scientific and technological contribution to what you are researching in India, and I have no doubt that the men and women a the NMM would be glad to help you with any information you need. --Seejyb 02:42, 20 August 2006 (UTC)[reply]

In the 19th century the Greenwich observatory was the center for accurate time measurement in the world. A telescope was set along the Airy meridian (once the zero of longitude.) Observers would press a button as each designated star passed exactly through the crosshars, recording electrically on a paper chart the time. This would be compared to the expected time of traverse. The master clocks were so regulated, and electrical time signals were transmitted to the UK, to Europe, and via the transAtlantic cable to America. There was a master Time Desk, which must have inspired H.G Wells for his book "The Time Machine." The same office regulated marine chronometers.(on edit: the marine chronometers were dropped off, not remotely set!) Paris time was defined as Greenwich Time less so many minutes and seconds. Devices for sunchronizing chronometers may have inspired Einstein when he was a clerk at the Swiss patent odffice. This process was replaced in the 20th century by atomic clocks. In a great tragedy, the actual zero meridian established at Greenwich by Airy, was moved a bit, detectable by GPS devices, apparently to placate the French.Edison 03:46, 20 August 2006 (UTC)[reply]

vacuum propulsion

i am writing a short sci-fi story and it includes a ship i want to fly by zero-point energy propulsion but based on actual theories that are being looked at for future use in real life. I would like to know some of the theories for zero-point energy propulsion, non are mentioned specifically in the zero-point energy section of this site. Through talking to a physics student i have come across two. but dont worry he made sure to stress that these theories would require technology beyond what we have today, so no crackpot stuff

Firstly was the theory that somehow you could change the waves of zero-point to a lorentz variable form, because apparently its nature normally is lorentz invariable so we cannot full its effects, and through the loretz force that would carry the ship like a sail

The second and best i have heard so far is the theory that zero-point energy could make negative mass or energy that can repulse stuff, so maybe an negative matter jet that repels the ship.

any other theories?

jamie olins

You mean vacuum energy ? Hmmm!--Light current 21:10, 19 August 2006 (UTC)[reply]

yea vacuum energy, the zero point field, apparently its a huge source of electromagnetism and energy in general but we only know its there according to mainstream science, there is not that i know of any method of harnessing it yet, all we know is that its huge and its there and it arises from 3 of the four fundamental force so if we could get at it, or make its waves tangibel, we could move spaceships easily, saw something on your site about it having enough energy to bend space-time and on another site about enough to boil the oceons of the world. but the problem is that up till now we cant, but there are theories, i named a few i have heard, got anymore? -Jamie olins

Really, it would be stupid to try to "harness" zero-point energy, because it takes so much energy to try to use it. We're better off using anti-matter or nuclear fusion if we get that advanced. Check zero-point energy. You'll have to read some science fiction to get ideas for how to use it, because we don't have any ideas yet. The closest thing we have now, in physics, would be the Casimir effect. Let me correct a few things. Zero-point energy does not "arise from 3 forces," it is just the lowest energy state. Negative matter does repels things because gravity is "opposite." — [Mac Davis] (talk)

Well we cant harness it now, because we dont have the technology, but it is there and large so maybe in the future we will be able too, and according to vacuum energy section it does arise from 3 of the fundamental forces at least [we are not sure about gravity] so there are no theories even i know we have no actual method yet, non at all?

Jamie

no need for anymore replies, found a site with some theories that fit my needs on the NASA website http://www.nasa.gov/centers/glenn/research/warp/ideachev.html, the first one is the first one i mentioned, but there are other ones there, they are in the the millis hypothetical drives section

jamie

AWW. I didnt think we had sucked everything out of this topic yet! Still maybe we get more that zero points?--Light current 23:58, 19 August 2006 (UTC)[reply]

Well feel free, if you can come up with something better than a differentual pressure sail, [cohering zpe behind the sail to push it] feel free. will check back. Jamie

What about the nuclear bomb idea? You let one off every so often behind a reaction plate and you keep accelerating the craft. THis was seriously being considered (by NASA I think)--Light current 00:54, 20 August 2006 (UTC)[reply]

See Project Orion (nuclear propulsion) for our article on this.-gadfium 01:17, 20 August 2006 (UTC)[reply]

Yeah thats the one. Good idea--Light current 01:32, 20 August 2006 (UTC)[reply]

Dreams what do they mean?

I keep having two dreams. THe first is where I need to get a couple of teeth filled (big holes). The second is where I still have to finish my degree and I can never quite make it. Do these dreams mean anything? You may refer to my User page to dtermine my personality if this helps.--Light current 00:08, 20 August 2006 (UTC)[reply]

You know, I just had a dream where I, and some freinds from high school who I haven't seen in a year, had a reenactment of early Australia. For some reason we were in a huge library, and we would fight to Beatles songs. If the Beatles song changed to an upbeat one, we would all go and sit down. I don't like this idea of dreams meaning something, and even if they do, how would anyone know? --liquidGhoul 00:34, 20 August 2006 (UTC)[reply]

I do think they mean something to the individual. But i cat afford to go get psychoanalysed (again) so Im asking here!--Light current 00:46, 20 August 2006 (UTC)[reply]

It just sounds to me like you're just afraid of cavities/dentists and not being able to finish college. Now give me a dream full of cigars and then we will have some real analysis to do. :-) StuRat 02:01, 20 August 2006 (UTC)[reply]

Or, you're scared of not finishing your dentistry degree. :) --liquidGhoul 02:06, 20 August 2006 (UTC)[reply]

OR, you're scared that your dentist hasn't finished his degree! --liquidGhoul 02:07, 20 August 2006 (UTC)[reply]

Yeah but I have finished (about 30 yrs ago) and yeah Im still scared of dentists. Do you think it indicates ther may be big holes in my life?--Light current 02:45, 20 August 2006 (UTC)[reply]

Were you worried about it at the time ? Maybe your anxiety from then is still with you. StuRat 02:49, 20 August 2006 (UTC)[reply]

Yes of course but not that worried.--Light current 02:58, 20 August 2006 (UTC)[reply]

Your user page says you edited Tap Changers. Some of my best days were spent fixing tap changers. Perhaps you are worried about the cavities seen in the copper or bronze contacts of the tap changer mechanisms. Or maybe Freud was right and puns are used in creating dream images. Edison 03:52, 20 August 2006 (UTC)[reply]

No I only studied them a bit. Never had to fix one. I like puns and ragmansa.--Light current 13:28, 20 August 2006 (UTC)[reply]

I had a dream about a liquid rubik's cube, and it spawned an entire discussion on the viscosity of glass, and possible crystalline structures there of, someone even thought it was some sort of 'homework'--71.247.125.144 14:33, 20 August 2006 (UTC)[reply]

Yeah I saw that!--Light current 19:00, 20 August 2006 (UTC)[reply]

The dream are the recreation thoughts/events expirienced by the person or he has engraved those in the inner mind.ansari–202.154.255.3 15:08, 20 August 2006 (UTC)[reply]

In Freud's Interpretation of Dreams, dreams always mean the opposite of what they appear to be saying on the face of them (because they have to disguise themselves to slip past the censor, of course). So maybe he would say that your dream about college is actually a fear of what will happen when you do finish college. I don't even want to touch the part about the "filling big holes", but rest assured Freud would have a most objectionable reading, as all dreams are forms of wish-fulfillment. ;-) (I think Freud's dream theory is pretty silly, by the way, but sometimes the act of thinking through dreams, like thinking through anything else, can be a therapeutic form of self-examination.) --Fastfission 15:45, 20 August 2006 (UTC)[reply]

I can't believe you guys. Dreams don't "mean" anything. This is totally evident for somebody who controls their dreams. Dreams are just something made up by your mind while you sleep. We don't know why, we don't know how. — [Mac Davis] (talk)

It is currently unknown where dreams originate in the brain and why, and there are theories ranging from "they are meaningless" (which I find more than little suspicious, given that the proximity of dreams to conscious anxieties and desires seems more than coincidental), to "they are some form of processing" (which strikes me as being more than little vague). While I doubt the psychoanalytic approach to dreams is very sound (it is more literary than it is scientific), the idea that dreams may be the result of unconscious processes is not primae faciae absurd, nor is there a good scientific understanding of them at the moment. The way I figure, if talking about them brings up insights that are helpful, then it's not a bad activity, whether or not one can actually describe the "meaning" of dreams in any literal sense. --Fastfission 19:00, 20 August 2006 (UTC)[reply]

Yeah thats what they mean Mac:It IS your subconscious trying to tell you something.--Light current 18:57, 20 August 2006 (UTC)[reply]

I have a lot of dreams about my teeth rotting and crumbling out of my skull. I know that this is 'supposed' to mean something significant but I have no idea what... --Kurt Shaped Box 16:07, 20 August 2006 (UTC)[reply]

It means your life is crumbling away...--Light current 18:58, 20 August 2006 (UTC)[reply]

You secretly want to be a ~~seagull~~ bagel, which, of course, requires losing all your teeth as a first step in the transformation. :-) StuRat 01:42, 21 August 2006 (UTC)[reply]

OKG StuRat where on earth do you get these ideas? LOL 8-))--Light current 15:52, 21 August 2006 (UTC)[reply]

That comment was meant for KSB, who has a ~~seagull~~ bagel fetish. :-) StuRat 17:05, 21 August 2006 (UTC)[reply]

Oh sorry I thought it was you who had a pet ~~seagull~~ bagel!--Light current 17:20, 21 August 2006 (UTC)[reply]

It's your subconscious' subtle, convoluted way of telling you...your teeth are rotting out of your skull. go see a dentist :) --Bmk 00:23, 21 August 2006 (UTC)[reply]

PS: I'm sure KSB has a lovely smile, despite dire dreams. --Bmk 00:23, 21 August 2006 (UTC)[reply]

I subscribe to the idea that a dream is the post-processing for your day. What would be the evolutionary advantage to a primate, dog etc. having dreams so they can psychoanalyse themselves? It has to be something to do with your brains ability to stay fit or useful, otherwise it wouldn't occur. Also, Freud is an idiot, I haven't heard of one of his hypothesise which have been rational. All women secretly want to be men? What an idiot.--liquidGhoul 00:34, 21 August 2006 (UTC)[reply]

Why would they want to be men?. THey can have one whenever! (I happen to be available at the moment)--Light current 01:11, 21 August 2006 (UTC)[reply]

Setting aside that Freud is to psychology what alchemy is to chemistry, dreams seem likely to be something that the brain is trying to rehearse in case the scenario arises. But there can be many, many reasons that a particular situation would be subject of a dream. Peter Grey 01:31, 21 August 2006 (UTC)[reply]

I prefer to call him Sigmund Fraud. :-) StuRat 01:42, 21 August 2006 (UTC)[reply]

I think you can probably call him anything you like. He,s not going to sue. (But what about his grandson Clement Freud--Light current 01:46, 21 August 2006 (UTC)[reply]

Yeah but my point is, these are recurrent dreams (not every night but say one a week or so). so is my subconcious trying to tell me something?--Light current 01:34, 21 August 2006 (UTC)[reply]

There are any number of books out there that purport to interpret the meanings of dreams. Given that dreams are messages from the subconscious to the conscious mind using symbolic representation, these interpretations might have some validity in a general sense, because societies tend to agree on the broad meanings of certain symbols. But be very wary of assuming that such an interpretation is true for a particular dream or series of dreams, experienced by a particular person. Only the person themself can really know what the symbol means for themself, and it might be a different meaning this time compared to the same symbol in a different dream at another time. To answer your last question, yes, your subconscious is trying to tell you something. But for anybody else to tell you what it means is to assume intimate knowledge of your psyche, which only you have. JackofOz 02:50, 21 August 2006 (UTC)[reply]

Or an analyst! OK Im off to bed now to sleep - perchance to dream? (Wm Shakespeare?) %-)--Light current 02:57, 21 August 2006 (UTC)[reply]

No, not even an analyst. They might have a bit more of an insight into some of the possibilities, but only you know the answer. And you do know. JackofOz 03:11, 21 August 2006 (UTC)[reply]

Do you really think he does? I'm not convinced most people are enough in touch with themselves to know that. Black Carrot 03:41, 21 August 2006 (UTC)[reply]

Yes I do. I operate on the basis that people always have their own answers within them. They might need a counsellor or a therapist in some cases to help them sort it out from all the other stuff that's inside, but it's there. The very fact that Light current is asking questions about the meaning displays a level of self-awareness. It means that he knows the dream is not just some random meaningless visual rubbish, but something of significance. Ask and you will receive (but not necessarily from the person you asked). JackofOz 03:53, 21 August 2006 (UTC)[reply]

This may be tangential to the current discussion (who am I to say) but I have heard that dreaming about teeth problems (as I do quite often) is an indicator of physical self-consciousness (which I do suffer from at times in the waking world) and dreaming about being at school/work in a hopeless situation is indicative of fear of failure (vague, I know). Of course, I don't claim that dreams correlate well to real life, but they sure are fun to ponder. --Jmeden2000 15:44, 21 August 2006 (UTC)[reply]

Hey you could be right JM. I am physically self conscious ( but incredibly handsome 9-)) nad I do have a fear of failure because it happens so often. So i think you have cracked it!--Light current 15:56, 21 August 2006 (UTC)[reply]