Wikipedia:Reference desk/Archives/Science/2007 March 15

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March 15

Want to disinfect clothes during washing but without disinfectant smell

I have a harmless skin rash caused by bacteria. I have been to the Doc and got some ointment for it which did work and clear the rash. However it now seems to have re-occurred, which from what I've read about it on the internet is not uncommon.

I suspect it may be lurking in my clothes and sheets.

Is there any safe odourless liquid that I can add to my washing machine to help disinfect my clothes? Or for that matter, to my bath?

Ordinary disinfectant could be used, but it does make your clothes smell. Bleach may also be effective, except it damages colours.

Does anyone know of anything else that could be used please? —The preceding unsigned comment was added by 62.253.48.122 (talk) 00:19, 15 March 2007 (UTC).

• Bleach and ammonia will both effect colored clothes. A -really- hot wash would probably kill most bacteria. For maximum hotness you could try taking everything to a laundromat and washing and drying it there with the washer and dryer on their hottest settings. --Peta 00:26, 15 March 2007 (UTC)

• Washing at 60 degrees C (140 degrees F) should kill most bacteria [PubMed]. Of course you also want to make sure that the rash is not caused by allergy to laundry detergent additives such as fabric softener or perfume. Gorm 10:36, 15 March 2007 (UTC)

From personal experience I find that over many washes, 1/3 cup of chlorine bleach per washload does not visibly affect colors, yet it eliminates the bacteria which cause that "wet washcloth" odor. However, the smell (and presumably the bacteria) easily survive many cycles of hot washing and extremely hot drying. I suspect that hot wet clothing acts as a growth medium for thermophile bacteria. --Wjbeaty 19:59, 16 March 2007 (UTC)

QUATS or Quaternary Ammonium Compounds are very powerful disinfectants that have little or no smell (depending on the compound). They might fit the bill. They are often used as the anti-bacterial component in dermatalogical preparations and so are reasonably kind to skin. A common commercial disinfectant that uses quats is Zoflora, which is basically Benzalkonium Chloride and perfume. EABlair

SMD VS. through hole

Thanks for taking the time in answering my question but I guess I didnt communicate my ideas well. What i meant by "converting" is to look for an SMD equivalent of a present through-hole varistor. In my case, the maximum continuous voltage of my through-hole varistor is 275Vdc and its maximum energy is 104J. I've looked up to the internet looking for SMD Varistors with the same or even almost equivalent parameters but the maximum contiuous vaoltage that I saw was around 56Vdc and worse for the maximum energy, the highest value that I got was 1.5J. that is why I was thinking that maybe some of the parameters of a varistor would be changed when it is "converted" from through-hole to SMD. —The preceding unsigned comment was added by Gfranz G (talk • contribs) 00:36, 15 March 2007 (UTC).

SMD components are typically smaller. The size of many thru-hole electronic devices are often grossly larger than they need to be, with most of the space being taken up by packaging, and some devices don't need as high power ratings, so resistors can be made the size of a period that can handle 1/100 of a watt. However, for power devices this is another matter, power devices need a certain physical size to be able to handle large amounts of current, voltage, and dissipate power. Interesting that you bring up varistors, because where I work, we have several automotive electronic devices that are completely SMD except for the varistors, and I assume it's because they just can't make a device (the varistor) that can handle that much energy into a SMD component, and if they could, it would have poorer characteristics and likely cost more than the "bulky" thru-hole component. Atropos235 04:29, 15 March 2007 (UTC)

I really appreciate that response sir. I think you really have a good point. You've helped me alot in my research. We will just saty with the through-hole varistor that we now have. thanks!

Is Miconazole nitrate safe to apply long-term to skin?

I have a harmless(?) skin rash called Erythrasma which is caused by Corynebacterium minutissimum. I had it in my groin and axilla. It was treated with a Miconazole nitrate ointment preperation and did almost disapear, but has now re-appeared in my groin. I have by the way already seem my doctor about this.

My question is, is it safe to apply a spray of Miconazole nitrate to my skin as a preventative measure over a period of months say?

Miconazole nitrate is also the active ingrediant in a spray sold in supermarkets etc in the UK under the trade name Daktarin used to treat Athlete's foot, so it is easy to get and use.

Is it nitrates or nitrites that are carcinogenic?

62.253.48.38 00:44, 15 March 2007 (UTC)

Wikipedians may not offer medical advice, therefore you should ask your doctor (or perhaps your pharmacist) about the safety of preventative treatments. Regarding nitrates and nitrites, i'm not sure either are a proven carcinogen. However, in the presence of amines, nitrites can form nitrosamine, which is a carcinogen (at least in animal models). Rockpocket 00:51, 15 March 2007 (UTC)

I think we take it as read that no med. advice is being offered.

Let me put it another way: is there any evidence that long term use of Miconazole is harmful?

Old age memory loss

Does the first sign of old age memory loss start with for example wanting something from another room and then not being able to remember what it was you went in the other room to get, or is this problematic at any age? Diligent 01:39, 15 March 2007 (UTC)

I think it happens to everyone. -Wooty Woot? contribs 01:43, 15 March 2007 (UTC)

It's pretty clear that memory efficiency gets worse and worse as you get older - but this is somewhat compensated for by older people adopting cleverer ways to remember and recall things. I have no clue what the first sign of the very gradual process is - I doubt that there is one single thing you could use to pin it down. The specific case you mention could be a symptom. SteveBaker 06:26, 15 March 2007 (UTC)

Your doctor would be a good person to discuss this with if it is a concern in your own life or that of someone in your family. We cannot give medical advice here. Edison 22:22, 15 March 2007 (UTC)

With regard to forgetting why you went to the other room, you might want to read The Magical Number Seven, Plus or Minus Two. If you're "multitasking" (move the laundry from the washer to the dryer, on your way, get the mail from the front door and put it on your desk, passing by, put the pencils back in the cup by the phone and, oh yeah, answer the ringing phone), it's not uncommon to exceed the cognitive limit and end up in the laundry room wondering why you're there.

Atlant 11:58, 16 March 2007 (UTC)

Solar Energy

what are the advantages of using solar energy and what are the costs as a alternative fuel for petroleum? —The preceding unsigned comment was added by 69.211.138.45 (talk) 01:51, 15 March 2007 (UTC).

• I suggest you start with Solar energy and Hubbert peak theory. Basically, solar energy is free, but equipment to make it and transport it consumes resources (including usually petroleum). Solar energy is not available at night unless some sort of energy storage is available. Also, not all areas are sunny, especially during the local stormy season. On the other hand, our oil will run out long before the sun will. In human terms, the sun is inexhaustible. Not true for oil. Johntex\^talk 02:27, 15 March 2007 (UTC)

Cancer and Tumors

I was looking at the cancer article and it mentions tumors, but do all cancer include tumors? Or can you have cancer and not have a tumor? —The preceding unsigned comment was added by 76.167.159.75 (talk) 02:33, 15 March 2007 (UTC).

All cancers have tumors, not all tumors are cancers. There's a whole section at the cancer article. - AMP'd 02:44, 15 March 2007 (UTC)

Check out Tumor as well... -- Scientizzle 02:57, 15 March 2007 (UTC)

What about leukaemia? It's a cancer but there's no tumour in sight, is there? Aaadddaaammm 03:04, 15 March 2007 (UTC)

I was thinking the exact same thing. Leukaemia creates bad blood cells, and I don't think those are considered tumors. --Wirbelwindヴィルヴェルヴィント (talk) 07:28, 15 March 2007 (UTC)

glasses

if a pair glasses increase in power, does it make the wearer's eyes even smaller than before? —The preceding unsigned comment was added by 219.88.175.202 (talk) 03:01, 15 March 2007 (UTC).

The power of glasses is usually measured in diopters. People with myopia (nearsightedness) use glasses with negative diopter values; those lenses are concave, while people with hyperopia (farsightedness) wear glasses with a positive diopter value, which are convex. Magnifying glasses are of the convex type, they will bend the light to make things appear closer or larger than they truly are, which would include someone's eye behind a pair of glasses. However, when someone says an "increase in power" of glasses, it could go either way, a more positive diopter would mean a more convex lens, increasing the apparent size of their eye, or a more negative diopter which would be a more concave lens, decreasing the apparent size.

There is another factor though, the distance of the lenses from the person's eye. As you notice with a magnifying glass, when you pull the lens away from the object under study, the image increases in size, and the opposite holds true with a concave lens, so a new frame for the lenses could also change the apparent size of the eye to an observer.

Read up on Optics, it's an interesting topic and you can do some neat experiments. Atropos235 05:01, 15 March 2007 (UTC)

If you mean, does it gradually physically change the shape of the wearer's eyes and possibly make his or her eyesight get worse, the answer is, as far as I know, no. Clarityfiend 07:01, 15 March 2007 (UTC)

is there a way to make glasses make my eyes still bigger but with the same power?

capacity of an electrical circuit

This is probably a ridiculous question, but bear with me, i don't think i'm very good at electricity.

As i understand it, each circuit in a house has a certain limit as to how much electricty can be pulled from it (15 or 20 amps or whatever i guess?). In other words, no matter how many receptacles you install on that circuit, you're always going to have to work within that limit, there's no way around it.

Assuming that all is right, here's where i get confused. I have always been taught not to plug too many things into a single outlet, because otherwise they'll catch fire and it'll be armageddon and so on. I can't see how this is the case, though, if what i said above is true. If there's the same limit on the capacity of the circuit whether you have one outlet or a hundred, why should it matter how many outlets my stuff is plugged into? They all go to the same place, right? How is plugging twenty things into one outlet (assuming the power strip or whatever is rated for it) less safe than spreading those things out amongst two or three outlets on the same circuit?

Have i been taught wrong or is there something i'm missing?

FYI: The reason i ask is, in my bed room i only have one receptacle. This is very annoying, because between all my computer stuff and my TV stuff and lamps and hair-straighteners and phone-chargers and so on i (obviously) have way too much stuff to fit into it, not to mention it's very inconveniently placed (which forces me to use extension cords, blah blah). So i'm debating trying to get somebody to install a new receptacle or two for me.

A much easier (and cheaper) option, though, would be to make use of our drop ceilings and just run an extension cord up there leading to like a $40 APS BackUps thingie on the other side of the room, so i can plug my 'puter junk in, and then leave a power strip plugged into the other outlet in the receptacle for the TV and stuff. My mom advises against it, though, due to the above too-much-stuff-plugged-in-makes-a-fire reasoning.

Opinions? ~ lav-chan @ 04:28, 15 March 2007 (UTC)

The 15-20 amp limit you mentioned is usually determined based on the gauge of wiring used in the house, which is then enforced by the appropriate selection of a fuse or circuit breaker. Older houses often used thinner wire that can only handle a continuous 15 amps safely, while newer houses will commonly have heavier gauge wire that can take 20. More to what you're saying, yes, theoretically it would be safer to plug 10 devices that each draw 1 A into a circuit than one 15 A device, but there really should be no danger because if things get unsafe (at least within the walls of the house) the fuse/circuit breaker will interrupt power.

However, just because the house won't catch itself on fire, doesn't mean that poorly designed devices plugged into the house can't. Computers and phone charger cords in my experience don't really cause much heat (unless they are confined in a small space with almost no airflow) like an ancient (50's) space-heater we have does, where the cord probably could singe stuff if it was left on for a long time. Some lamps can be poorly made, thin lamp cord + high wattage lamp could get hot, but anything made this decade should be fine, especially if it has a UL symbol on it.

In short, using a power strip is OK, just don't cover it up under blankets or dirty clothes, let it get some air. Atropos235 04:47, 15 March 2007 (UTC)

The U.S. Consumer Product Safety Commission estimates that about 3,300 residential fires originate in extension cords each year, killing 50 people and injuring about 270 others, and recommends against using them in place of permanent wiring,[1] as does Underwriters Laboratories[2] and the United States Fire Administration[3].—eric

Fundamentally, there's no difference between plugging many appliances into many different outlets (assuming those outlets are on the same circuit), and plugging the same appliances into a single outlet using a power strip. There's a least two reasons why extension cords tend to be more dangerous, though.

First, the thickness: The required thickness of a piece of wire, whether it's an extension cord or Romex installed in your walls, is determined by the current through the wire, and the thermal environment of the wire. The more current you put through a wire, the more heat it generates. The thinner the wire, the more its resistance, so the more heat it generates for a given current. The wire must stay cool enough that it doesn't melt or burn its insulation, or anything else nearby.

Permanently installed wiring is hidden in the walls, where the code writers assume that it is fairly well insulated thermally. This means that it will take only a little bit of heat to get the wire very hot, so it's important that the wiring generate very little hit. Typical houshold wiring is 14 gauge, fairly thick. Whoever designs the extension cord assumes that it will just be sitting out in free air, so it doesn't matter if it generates more heat, because the environment will keep the extension cord cool. A typical extension cord is 16 or 18 gauge; higher gauge is smaller, so that's thinner.

Second, and possibly more important, extension cords are more subject to mechanical damage. Permanent wiring is safely behind drywall, but extension cords tend to get stepped on and abraded.

I'd get an electrician to run a new outlet. They might be able to just run armored cable in the suspended ceiling, like they do in commercial buildings, in which case it would be fairly cheap. Modern building codes tend to require multiple outlets on multiple circuits in many rooms (especially kitchens etc.), which is very convenient. If you don't run a new outlet, it's probably safer to run the extension cord in the ceiling than under a rug. 24.91.135.162 11:28, 15 March 2007 (UTC)

That's helpful (all three of you), thanks. ~ lav-chan @ 18:58, 15 March 2007 (UTC)

One factor in addition to basic amperage the circuit can carry is power quality. When plugs are plugged into extension cords I have seen power quality problems due to the higher resistance in the ground path. The more plugs there are in series the worse it is. Outlets generally seem to have more solid connections. Edison 22:17, 15 March 2007 (UTC)

Penguins and white bears habitat

Why polar bears live only in Arctic but not in Antarctic? Why penguins are confined to the Southern Hemisphere and are absent from Arctic?Fo63 04:37, 15 March 2007 (UTC)

And while we are at it, why are kangaroos found only in Australia and not on the North American plains, and why are gila monsters found in North American deserts but not Australian? Gee, maybe we could generalize the question to "why is every species where it is instead of a similar environment on another continent?" The answer is historical contingency [4]. alteripse 05:09, 15 March 2007 (UTC)

Basically, if you are a cold-weather animal and you evolve at the North Pole, you have no way to get to the South Pole without crossing the insane temperatures of the Equator to get there...and vice-versa. But in any case, there are very significant differences between the two poles. For one thing, you can get from warmer weather climates to the North pole by walking and swimming short distances - so a group of warmer-climate bears could gradually move further north, evolving the adaptations needed for severe cold. But the antarctic is a long way from any other continent - far too far for a land animal to swim. Birds, on the other hand, could have flown there - then evolved to lose their flying ability - which might interfere with efficient swimming or something. Fully evolved penguins are like ducks though - they can happily bob around on the water without needing to expend effort to avoid drowning - so Penguins could have been blown off course and over to the antarctic at some time in the past. SteveBaker 06:21, 15 March 2007 (UTC)

And penguins are pathetic. The only reason they aren't extinct is that there are no predators (such as bears) there to eat them

Dear anonymous. I think you will find that penguins are awesome. Yours sincerely, Capuchin 13:33, 15 March 2007 (UTC)

Yes! They are indeed awesome. Ungainly on land, granted - but underwater they are graceful, fast, highly effective. And in any case, Penguins do indeed have predators - Leopard Seals, Killer Whales and other birds that steal their eggs - to name but three that I know off-hand. SteveBaker 15:04, 15 March 2007 (UTC)

Don't forget the Penguin's biggest enemy: Batman. Clarityfiend 17:10, 15 March 2007 (UTC)

You can see how birds evolve into penguin, see Great Auk. 202.168.50.40 23:26, 15 March 2007 (UTC)

Or indeed, the Great Auk can tell you that we did, kind of, have penguins in the northern hemisphere, or very like. The penguins are still around, unlike the great auk, because we couldn't get to themoriginal research... Skittle 23:48, 15 March 2007 (UTC)

Has there been any research in the effect of visual cues on the perception of temperature?

For instance, let's say I have a red tube, and I have it cooled to a low temperature. And then I have a blue tube, and I have it cooled to the same temperature. And then I ask random people to touch the red one, and record the apparent temperature on a comparison scale. Then I have a separate group of random people to touch the blue pipe, and record the apparent temperature. Have there been any tests like this, in order to test whether preconceived notions about colors (red = hot, blue = cold) affect the perception of the temperature? And of course, the experiment could also be reversed, with the tubes heated instead. Thoughts? --Ķĩřβȳ♥ŤįɱéØ 07:02, 15 March 2007 (UTC)

Good question. A search of PubMed reveals a study that appears related, but not using your exact experiment. PMID 1155649 reports that "hot/red, warm/yellow, cool/green, cold/blue" associations are a learned trait and thus have a cultural, rather than a evolutionary or physiological, basis. Rockpocket 07:42, 15 March 2007 (UTC)

I agree - it doesn't seem likely that evolution could get us "red=hot" because only things that are literally 'red-hot' would look like that - and in nature, only stuff like lava flows is ever that hot and I doubt that enough early humans ever got close enough to lava (and survived) to have any evolutionary pressure. Like a lot of colour "meanings", it's highly cultural. We're more likely to have evolved "Red==Ripe & Delicious", "Green==Unripe or Leaves, avoid", "Blue==Severely mold-infested!" SteveBaker 14:49, 15 March 2007 (UTC)

I don't know whether there would ever be an evolutionary advantage to associating colours with temperatures. Humans have resonable enough temperature sensors that it seems unlikely to me this would have any real advantage. I.E. even if there there was some learned association, I doubt there would be an evolutionary reason an inate ability will be favoured evolutionary wise Nil Einne 15:10, 15 March 2007 (UTC)

I guess the more interesting question is whether all human cultures make the same basic colour/temperature associations. If so, there may indeed be some inherent element, a bit like Chomsky's theory of universal grammar. Rockpocket 18:10, 15 March 2007 (UTC)

Science Magazine

Hello I've been reading New Scientist for the past two years and really like it. Now that my subscription has come to an end I'm considering trying a different magazine. Unfortunately individual editions are not available for purchase where I live so I'd have to buy a subscription straight away. I was thinking maybe trying Scientific American. Could you recommend general scientific magazines, which one(s) do you think are better for a non-scientist who likes to read about science? Thank you 81.242.185.120 11:15, 15 March 2007 (UTC)

IMHO, Scientific American is at about the same technical level as New Scientist - but it's less like a newspaper and more like a typical science journal compared to New Scientist. I think you'll like it. The biggest problem for me when I switched was that New Scientist is weekly - Scientific American is only monthly - which left me frustrated because I had nothing to read. Neither New Scientist nor Scientific American are 'peer reviewed' - which makes them a little less reliable than other scientific journals - but since peer review takes time, it means they can carry the breaking stories months sooner than their competitors. If you are ready for something a little more 'hard core' (and peer reviewed), you might want to check out Nature (Monthly, very well respected, peer reviewed, but harder reading than Sci-Am or NS) and Science (Weekly, peer reviewed and more "newsy" than the others - also harder reading than Sci-Am/NS). Those are the only journals that come to mind that cover a broad spectrum of the sciences - most others specialise in one field or another. I suggest you visit a library (they usually have back-editions of these magazines) - or perhaps a book store or good magazine stand - they should have Scientific American...and maybe Science. SteveBaker 14:41, 15 March 2007 (UTC)

How do you find the focus of SA compared to NS? I've never really read SA but I feel NS (which is British) provides a resonably international focus and often wonder if SA is as good or has too much of an American focus. It's probably primarily the name that makes mean doubt SA tho which doesn't really make sense I guess Nil Einne 15:05, 15 March 2007 (UTC)

I don't really see much of a spin or other bias in SA. My threshold for that kind of stuff is usually low, especially on anything labeled "Scientific", but I'm an American, so what do I know. Atropos235 00:41, 16 March 2007 (UTC)

Spin is one consideration, but I was thinking more on their coverage in terms of research, political issues etc. Nil Einne 12:51, 16 March 2007 (UTC)

As a minor correction, Nature is also weekly. Dragons flight 17:03, 15 March 2007 (UTC)

I wouldn't recommend a subscription to Science or Nature to someone who has been reading New Scientist without them looking at it in their local library (or wherever else) first. The articles in them are usually very high-level, and even someone experienced in one field would be baffled by some of the other fields they cover. Scientific American is a nice choice, often authors that publish papers in the other journals write a more user-friendly, approachable article for SA, so yes, while it is not peer-reviewed, the articles are not themselves novel, instead based on research first published elsewhere. Weekly vs. monthly...that's up to you. On a personal note, I've had a subscription to SA since 1998, and through a combination of a few people giving me gift subscriptions and me buying them, it won't run out until 2012. Atropos235 19:27, 15 March 2007 (UTC)

I personally prefer Scientific American over New Scientist and Discovery. [Mαc Δαvιs] (How's my driving?) ❖ 20:57, 15 March 2007 (UTC)

I think he means Discover there. --Anon, March 15, 2007, 23:30 (UTC).

Yep. I was thinking about the channel when I wrote that. [Mαc Δαvιs] (How's my driving?) ❖ 00:19, 16 March 2007 (UTC)

Could you actually give reasons and explanations for what you prefer about it over the others? Otherwise you've just given your preference, which is facinating but doesn't really help the person make a decision. Skittle 23:37, 15 March 2007 (UTC)

I would, but I can't say why. I just like SA better. Discover is too thin too. [Mαc Δαvιs] (How's my driving?) ❖ 00:19, 16 March 2007 (UTC)

So no feeling at all then why SA is better then NS? Nil Einne 12:45, 16 March 2007 (UTC)

Scientific American's articles are written at a level high enough for someone who has a better-than-average knowledge base to enjoy. Magazines like Popular Science are really off-putting to me because the articles contain no skepticism whatsoever, and they're written to be just that, popular, not informative. On the other extreme, the Science and Nature journals are extremely thick (intellectually). Don't get me wrong, they're great for journals, and that's where you'll find all the cutting edge stuff, and it's a great reference if your library has a bunch of the previous issues (I actually just dug an article out of Science for a project), but it's not really for reading through. SA is the happy medium for me, where I can pick up an issue and read it cover to cover, understand, and enjoy it. For a weekly science fix, I like the Nature podcast and Talk of the Nation - Science Friday (on your local NPR station on Fridays). Atropos235 00:38, 16 March 2007 (UTC)

Oh, NOVA...another weekly fix. Not really a magazine...but it can be very interesting. -- atropos235 ✄ (blah blah, my past) 04:19, 16 March 2007 (UTC)

I thought Nature and Science were out of the question? Those are journals, not magazines. For TV shows I also recommend Scientific American Frontiers, which you can watch on PBS or the iTunes music store, or http://pbs.org along with NOVA. [Mαc Δαvιs] (How's my driving?) ❖ 06:50, 16 March 2007 (UTC)

Nature and Science are sort of hybrids. They have magazine type parts (editorial, news, book reviews, job listings...) and straight journal articles. The vast majority of academic journals have nothing but the journal articles. You would probably enjoy the magazine sections, but I think that is less than half of the pages. ike9898 17:44, 16 March 2007 (UTC)

Veins

Are bodybuilders veins that become visible (like in their arms by their bicept) because of the muscle pushing on the vein or do the veins actually get thicker and bigger?

It's a combination of the muscles being a firmer base for the veins and the bodybuilder having less body fat to mask the veins. Anchoress 18:40, 15 March 2007 (UTC)

Note that the veins do actually get larger as well. More muscle = more tissue which requires nutrients and oxygen = more blood required = bigger tubes. TenOfAllTrades(talk) 19:18, 15 March 2007 (UTC)

Vasodilation may be a factor also, I bet you get pretty warm injecting steroids working out. Rockpocket 19:45, 15 March 2007 (UTC)

The veins do get bigger too. I've no personal experience with body building but when I was a regular climber the vasculature on my forearms clearly got bigger and more visible. This was true for my climbing friends too. None of us had the 'pumped up' look that body builders get, in fact you probably wouldn't notice the extra muscle on a climber until they used it. Now I'm in sedentary middle age the veins on my forearms have shrunk back to a more normal size. EABlair

How Do E-Mail, FTP, Newsgroups and Message Boards, Mailing Lists, Chat Rooms, and Instant Messaging Work?

Not sure about the bodybuilding question. Your second question I can answer. Internet e-mail is basically an easy way of transferring messages between computer systems. Modern e-mail systems typicall use SMTP for the protocol. FTP stands for File Transfer Protocol, and it is a way to transfer files between computers easily. FileZilla is a popular FTP client. Newsgroups are a way of getting "news", whether text or binary, from a central server. NewsLeecher is one client I can think of top of my head. Internet message boards are basically places to discuss. Mailing lists are basically lists of e-mails which are used by e-mail programs to massively send to all e-mails. Chat rooms on the Internet are in the form of Internet Relay Chat, an Internet protocol. IRC basically allows real-time communication on public servers. Instant messaging same thing, except proprietary servers with extra features. Sorry if I missed stuff, quick response. Splintercellguy 18:27, 15 March 2007 (UTC)

about algae growth

normally if an aquarium placed outside of the house, the water turn to become green.. this is because of the algae growth.. algae grow with the sunlight and a proper temperature.. well my question is will the algae grow eventhough there is the sunlight but the temperature isn't proper for the algae..

There aren't too many temperatures where algae won't grow, except solid ice, or boiling. --Zeizmic 22:00, 15 March 2007 (UTC)

Coffee Question

(split from above question by Atropos235)

and another question will a coffee moleculs can be break or separated after the plain water mixed with the coffee powder.. and what are the chemical or nature way to separate back the moleculs..

thanks for the time and patients sir/madam..

Er, well for starters, coffee grounds do not consist of a single type of molecule by any means. They are a mixture of all kinds of organic compounds, which probably interact with water in different ways. -- mattb @ 2007-03-15T20:49Z

You might start be reading about solutions, the chemical name for the special type of mixing of molecules in coffee. Some of the chemicals may be in suspension, while others are chemically dissolved. Molecules in solution can not be easily separated by physical means (this is why the coffee liquid goes right through the coffee filter! However, the coffee grounds do not dissolve, and therefore can be separated out (i.e. they stay behind after filtering). Hope this gives some pointers towards the answers you seek. Nimur 20:54, 15 March 2007 (UTC)

Since you ask about coffee powder, it is possible you mean instant coffee, which dissolves in water? If so, in the powder, each grain of powder is made up of lots of different sorts of molecules, because coffee is made of more than one type of molecule. It is a mixture. In the powder, these molecules are held to each other by various bonds. Each grain of powder is solid. When you mix this powder with water, the water molecules (which are moving around, because water is a liquid) will bash into the solid grains of coffee. This will cause the molecules on the outside of the grain to break off and float around in the water; these molecules are said to be 'in solution'. Eventually, if there's enough water for the amount of coffee, all the molecules that made up the solid coffee powder will be in solution. So the molecules do not break, but they do seperate from each other. You can seperate the coffee molecules from the water molecules by evaporating the water away, although a small number of the coffee molecules (responsible for the coffee smell) will also evaporate. You could solve this problem by first evaporating off the smell molecules, condensing them and storing them, then evaporating off the water to leave the solid coffee behind, to which you could readd the smell molecules. And that, greatly simplified, is how they make instant coffee in the first place! Skittle 23:31, 15 March 2007 (UTC)

It is relatively easy to get pure caffeine from tee or coffee using acid-base extraction followed by recrystallization. Cacycle 05:27, 18 March 2007 (UTC)

Loss of memory caused by aging

What are some of the clever ways old persons use to overcome the effects of their gradual loss of memory? 71.122.101.15 19:36, 15 March 2007 (UTC)

Constant social interaction seems to be important. I'm sure you can find numerous scientific studies which support this idea. Nimur 21:33, 15 March 2007 (UTC)

Forgetful people in general have lots of tricks. Lists and daily calendars are widely used, as well as personal organizers which alarm to remind of appointments. Pill minders (boxes with compartments) help keep track of whether medicine has been taken. There are electronic beepers which can be used to find important objects. Then there is the old trick of checking whether the toothbrush is wet. One common trick is putting a note where it will be seen: on the refrigerator or inside the front door, with a reminder. Some phone message systems allow you to prerecord a phonecall to yourself with a reminder. Edison 22:13, 15 March 2007 (UTC)

Technology

I can't think of any way technology has improved product safety. Can anyone help me? I can only think of ways technology's made things more safe for workers. Also, I don't really understand the control system article. A question I have is to "Describe the stages of a control system you have studied." I have to specify the input, process and output (each is worth 2 marks). I haven't studied a control system so I don't know what the article is talking about. For the thermostat example at the control system article, I would guess that the input would be whether the room temperature is lower than the temperature the thermostat is set at (A) or not (B). Would the process be to turn the heating on (A) or to leave it as it is (B) and the output be (A) more heat to the radiators or (B) be no heat to the radiators? Thanks, My Username is... 20:10, 15 March 2007 (UTC)

As for the product safety issue, wouldn't seat belts count? Airbags? Dismas|^(talk) 20:12, 15 March 2007 (UTC)

Yeah, they would! The only thing I could come up with was making edges round but that's always been done (except on knives!) Thanks, Dismas! My Username is... 20:14, 15 March 2007 (UTC)

I don't really understand the question, but I'll have a go. How about using technology to test donated blood for infectious diseases? Blood is the product, the technology is used to make it safer... Aaadddaaammm 20:31, 15 March 2007 (UTC)

For the thermostat example, I think it would go a bit more like this (I'm kind of assuming it's analogous to a function in programming):

• The input is the value of the actual temperature (measured by a thermistor or thermocouple)
• The process is comparing the input temperature to the setpoint temperature
• The output is the signal sent to the heating/cooling equipment to adjust the temperature

— Matt Eason ^{(Talk • Contribs)} 20:35, 15 March 2007 (UTC)

Every day, engineers and scientists make your life safer and you probably don't even know it. Bridges, highways, automobiles, electric lighting, cell phones, textiles, medicine, ... you wake up each day without electrocuting yourself, poisoning yourself, getting crushed, ... Yikes. I don't even know where to begin. Think of anything you do, and then think about all the ways that you might die by doing it. You can guarantee that somebody else has thought of a technological solution to make sure you don't.

Regarding Control Systems, think about the last time you were in a car. The driver presses the brake pedal. This is the input. The car's hydraulic system senses the pedal, applies the brakes in a controlled, safe way to slow the vehicle without flipping over or crashing. This is no easy task! Applied too rapidly, the car would swerve and you would slam through the front window. Applied too slowly, the car will keep going and hit whatever you tried to avoid. Somewhere in the middle is a safe, controlled braking time. This process may involve mechanically calibrated pipes or hoses, a master cylinder, and electronic and computer assisted control such as ABS. Finally, the output is a mechanical clamping of the wheel (the brake shoe), and the safe slowing of the vehicle.

I suggest you think about all the things you use every day. Every little task is very simple, but imagine what it takes to make it so simple. THAT is technology, and it is everywhere. Nimur 21:04, 15 March 2007 (UTC)

Thanks for all your help I understand it now (I think!) My Username is... 21:16, 15 March 2007 (UTC)

Additionally mass production has reduced hugely the amount of goods that are of differing quality. Consistency and reliability are huge. As things are made not in small batches but by the millions the process is so well honed that there is minimal wastage (as that drives up costs) and maximum repetition quality. Technology has also allowed for things such as computer-model testing of quality/safety features. Measuring using lazers has helped make sure that the quality of huge products (such as ships/planes) are made to a degree of accuracy that is almost mind boggling. Automated control of production and automated stress/safety testing has led to an increasing in qulaity and therefore safety. Of course many will argue that because mass-production is so popular the real quality is now found in batch/small scale production. This shouldn't be taken to mean that unautomated-production = higher quality, rather that maintaining quality over millions of units is harder than over just 100s. Hope this helps ny156uk 21:55, 15 March 2007 (UTC)

Is that more because people equate quantity with reduced quality; people's desire to possess something unique?

Accidental electrocutions have been reduced in number by the requirement that all bathroom and kitchen outlets where an appliance might be close to a tub or sink be protected by Ground fault circuit interrupters which was a simple concept borrowed from the utility industry. Edison 22:02, 15 March 2007 (UTC)

Product: Shaving Razor

Technology: Safety Razor

202.168.50.40 23:16, 15 March 2007 (UTC)

As nimur has already mentioned, there are many, many ways in which products have been made safer by technology. If you think about it, the product of food, was made safer by one of the early technologies of fire... Nil Einne 09:17, 16 March 2007 (UTC)