Wikipedia:Reference desk archive/Science/2006 July 9

From Wikipedia, the free encyclopedia

Humanities Science Mathematics Computing/IT Language Miscellaneous Archives

The page you are currently viewing is an archive page. Whilst you can leave answers for any questions shown below, please ask new questions at one of the pages linked to above. This will insure that your question is answered more quickly.

< July 8 Science desk archive July 10 >

Contents 1 Hatred between gulls and moonpies 2 What's the best.. ? 3 Running MAC apps on a Windows box 4 Physics 5 Hallucination 6 Does twisting add strength? 7 Laptops needing harddrives 8 Bumblebee stings 9 Spinach 10 sun-oriented structures

[edit] Hatred between gulls and moonpies

The above question inspired me, how can anyone hate a marshmallow filled dessert? They're just so delicious, it boggles the mind--152.163.100.74 01:04, 9 July 2006 (UTC)

I blame the Jews. --George 01:06, 9 July 2006 (UTC)

Well, I am a Jew, and the idea of a marshmallow filled dessert sounds pretty gross to me. - MSTCrow 01:11, 9 July 2006 (UTC)

Moonpies? Try a pav instead. BTW, what is it with gulls and maglevs? Grutness...wha? 01:51, 9 July 2006 (UTC)

I think it's the gulls and magnetos that are the real enemies. User:Zoe|^(talk) 03:07, 9 July 2006 (UTC)

Useful advice: If a gull won't eat it, you probably shouldn't be eating it yourself. --Kurt Shaped Box 10:55, 9 July 2006 (UTC)

Yep. But the reverse does not apply. Gulls eat all sort of shit that isn't safe for humans. JackofOz 00:44, 12 July 2006 (UTC)

It always makes me wonder just how strong a gull's immune system actually is. They seem to be able to consume even the most putrid of matter without becoming ill - in fact they seem to thrive on it. Fun fact: gulls will not eat quorn (the one time I threw some to them, one bird ate a small piece, immediately horked it back up, looked at it suspiciously, then started protesting very loudly both to me and the other gulls), which leads me to believe that there is something very, very wrong with it. --Kurt Shaped Box 00:51, 12 July 2006 (UTC)

[edit] What's the best.. ?

Whast's the best place/method on the internet to find lots and lots of free high quality pr0n?--Question1 02:57, 9 July 2006 (UTC)

I'll give you a hint: it has nothing to do with the Wikipedia reference desk. Sorry. —Keenan Pepper 03:14, 9 July 2006 (UTC)

LOL - but you have to give him credit - he tried to ask it in sort of a scientific-sounding way. --Bmk 03:34, 9 July 2006 (UTC)

If you're using Google Image, did you remember to turn SafeSearch off? That step is key. —Keenan Pepper 05:29, 9 July 2006 (UTC)

There's even a pron redirect. I thought it was a taipow (no, no redirect for that). DirkvdM 09:24, 9 July 2006 (UTC)

www.google.com -- Koffieyahoo 01:45, 10 July 2006 (UTC)

go to www.discretesex.com or www.jonsvids.com =) many many free videos that lead to sites with even more free videos =))) -PitchBlack

[edit] Running MAC apps on a Windows box

Is there any way to run simple, terminal programs written for the MAC on a pc? Is there a virtual machine, or a compability layer or an emulator or anything? Oskar 06:43, 9 July 2006 (UTC)

I'm confused. The title says Mac apps, the question refers to terminal scripts. Which is it? OS 9 or OS X? If OS X, terminal scripts are sh or bash scripts. bash can be run on Windows (somehow I assume you are not using Linux) if you get Cygwin. Or maybe I misunderstand your question, what is it you want to run? There exists an OLD Mac 7 emulator, "Executor"... --GangofOne 07:33, 9 July 2006 (UTC)

The new Macs are 80x86 based, so they're pc's in a sense, but that's probably not what you meant. DirkvdM 09:27, 9 July 2006 (UTC)

[edit] Physics

This IS a homework question, but id really appreciate if someone could explain HOW to do it (I've looked in the textbook and can't find the appropriate method) 'A runner, starting from rest, speedsup uniformly to a velocity of 6.0 m/s in 4.0 s. continues at this velocity for another 10s. and then slows down to a stop in 2.0s Draw the velocity time graph for the runner (done that) and determine how far the runner has travelled (This is the part I'm stuck with). Help is appreciated as i do need to study for the exam tomorrow. Thank you in advance.

Break the calculation into the three parts, each of which has a different acceleration (in one case, the acceleration is zero). Use s = u . t + (1/2) . a . t² (can't remember what formula this is, but you should have been taught it more recently than I was; it's one of a set of three). In fact, this formula makes more sense if you realise that your task could also be expressed as "give the area under the graph", but I don't remember being taught that. Notinasnaid 07:50, 9 July 2006 (UTC)

Ah found it. See Equation of motion#classic version. The first three of the "classic" equations shown are so important you will be expected to remember them and use them during any exam. Notinasnaid 07:57, 9 July 2006 (UTC)

Ok I think I understand now thanks all.

you have a graph of velocity vs. time, so just take the area under the graph. Just look at the units, m/s * s = m. That's visually what the mathematics/calculus is doing. -Kyle

[edit] Hallucination

What is the specific name of hallucinatory effect of seeing animal or other creatures heads on a person (drug influenced or otherwise)—The preceding unsigned comment was added by 70.69.221.200 (talk • contribs).

The closest I can find in the OED is zo'oscopy: a species of hallucination in which imaginary animal forms are seen.--Shantavira 14:45, 9 July 2006 (UTC)

What a wonderful word. That's why I love the OED. Perhaps you could use this as the basis for a more fantastical neologism, like monstroscopy; or a more specific neologism, like zoocephaloscopy: a hallucination in which animal heads are seen; more specific yet, circumcorporeal zoocephaloscopy: hallucination in which animal heads appear around a body—pretty close, eh? Bhumiya (said/done) 23:07, 9 July 2006 (UTC)

Or even chimeroscopy, that of seeing hybrid creatures, perhaps. Confusing Manifestation 01:17, 10 July 2006 (UTC)

[edit] Does twisting add strength?

Is a twisted structure stronger than a non-twisted structure of the same basic shape? If built from the same materials, on the same scale, would this be stronger than this? I have a special fondness for spiral architecture and I was wondering if there's any actual advantage in it. Intuitively, I would think so, but I'm no architect. Thanks! Bhumiya (said/done) 15:05, 9 July 2006 (UTC)

You seem to be talking about compression strength, so I would say no. There might be an advantage in making wind load more consistent, by not presenting a single flat surface which can act as a sail, but I suspect the cost savings of making a rectangular box would allow for enough overdesign to compensate for this. Spiral shapes do help in ropes under tension, to secure the strands together and ensure that the force is distributed evenly to the strands. In architecture, however, I suspect it's purely for aesthetics. StuRat 17:05, 9 July 2006 (UTC)

.

Not sure it's stronger for it, but you might like to see this famous example of twisting. The folk stories of "how" this happened are charming (Chesterfield). --Dweller 10:25, 10 July 2006 (UTC)

[edit] Laptops needing harddrives

Why do laptops still use harddrives? Would miniSD's allow for a more compact design and eliminate the point of failure that is inherent in spinning drives?

For some applications – some portable music players come to mind – the durability and lower power requirements of solid-state storage do make that option more attractive. However, the price per gigabyte of storage is still much higher for solid state memory compared to spinning hard disks. A hundred gigabyte solid-state drive would cost thousands of dollars. TenOfAllTrades(talk) 16:21, 9 July 2006 (UTC)

I think you're right, and shortly we may start to see laptops without hard drives. We may eventually see the same thing in desktop computers, but the weight and size of hard drives is less of an issue there, and cost is more of an issue, so it may take a while. The heat and noise of hard drives is also a negative which will be fixed by going to SD cards. StuRat 17:10, 9 July 2006 (UTC)

Most hard drives have a data transfer rate much higher than even the fastest SD cards, if I'm not mistaken. Sum0 17:31, 9 July 2006 (UTC)

The reason is a limitation on miniSD and related technologies: they all use flash memory, which has a limited number of write cycles. Unless you are using an operating system designed to be used on flash memory, the repeated use (for instance, virtual memory, temporary files, and atime updates) will wear it down too quickly. A hard disk drive can be written to many more times than flash memory (and, in fact, the main factor on wearing it down would be either the bearings failing or stiction). Some modern systems are being designed with flash memory in mind; for instance, the OLPC project laptops (see $100 laptop). --cesarb 18:01, 9 July 2006 (UTC)

Write cycle limits are a problem but they are improving all the time. They are also getting better at fault tolerance so they will continue to work without interruption as cells go bad. Price per GB is also improving constantly. Samsung is working on viable solid state disks for small laptops and tablet PCs, as seen in this somewhat dated article Arstechnica. The key benefits to solid state disks are high g-force tolerance (translated: drop-proof) and low energy consumption (around 5% of platter type disks). In short, they aren't out yet but be on the lookout for this technology, it has the potential to dramatically improve portable computing.

[edit] Bumblebee stings

I'm puzzled by the evolution of this. Since the use of the sting kills the bee, surely the first bees to develop this mutation should by definition have not survived to pass on the advantage? --Dweller 19:14, 9 July 2006 (UTC)

Worker bees, the ones most likely to sting, never reproduce anyway. See: honeybee life cycle and bee sting. Dragons flight 19:21, 9 July 2006 (UTC)

Then how have they evolved at all? --Dweller 19:48, 9 July 2006 (UTC)

There is only one breeding female per hive, the queen. Most of her children are infertile worker bees that do the grunt work and protect the hive. So basically, the queen evolved the ability to create an army of sterile slaves to protect her own genetic heritage. Dragons flight 19:57, 9 July 2006 (UTC)

I think you misunderstood my (second) question. Since the workers cannot breed, how do they evolve? --Dweller 20:07, 9 July 2006 (UTC)

'They' don't, they're all the same species, but the Queen that produces more effective worker bees, is more likely to live long enough to reproduce, where as a queen that produces ineffective worker bees, isn't as likely to live long enough to reproduce--71.249.9.254 20:13, 9 July 2006 (UTC)

From what I remember from the article, the use of the sting only kills when used against mammals, not other bees, wasps, etc. Emmett5 20:15, 9 July 2006 (UTC)

(bringing it back here) Not sure I buy that... a tiny freaky mutation in an individual might help its survival and therefore "protect" the mutation. But this individual is hardly going to make much of an impact on the survival chances of the queen. --Dweller 20:21, 9 July 2006 (UTC)

Because queens make the workers, mutations in her can allow her to create more effective workers. Hence workers evolve through evolution in the queen. Dragons flight 20:25, 9 July 2006 (UTC)

Evolutionarily speaking, you can think of a hive as a single organism. The worker bees are like legs or organs of the queen, except they are physically distinct. It's sort of like asking why a macrophage (white blood cell) engulfs foreign bacteria, when doing so is fatal to the macrophage. It's not autonomous; it's part of its organism (i.e. you). Likewise, a worker bee is part of the hive organism because it does not reproduce. This idea taken to its extreme is called the gene-centered view of evolution. --Ginkgo100 ^{talk · contribs} 20:54, 9 July 2006 (UTC)

The fact that queen bees have smooth stingers and can sting mammals more than once without dying supports this view. The queen has evolved to survive, while the workers have evolved to be useful to the queen. Crazywolf 21:06, 9 July 2006 (UTC)

1. I'm not even sure bumblebee bees have hives. 2. Honey bees' stingers can repeatedly sting another insect, so I would imagine that most threats to bees come from other predatory and/or thieving (of their honey) insects, so it didn't make much sense to bother if the occassional bee happens to come across a mammal with much tougher and elastic skin and ends up kiling itself. - MSTCrow 21:34, 9 July 2006 (UTC)

1. Bumblebees do have hives, but they are small and do not resemble the honeycomb hives of honey bees.

2. Bumblebees' stingers are the smooth ones. Honeybees do have barbed stingers. And while honeybees are able to sting other instects in certain circumstances withuot dying, they have many predators which are not insects, see the predator section of honeybee.

It seems that the bumblebees evolved in a more individualistic fashion, what with their non-self-lethal attacks and ability to mate with non-queen females, and the honeybees evolved more as an organism, as described above.Tuckerekcut 01:37, 10 July 2006 (UTC)

If i remember correctly, Dawkins' The Selfish Gene makes a very elegant explanation for how hive communities evolve and why it makes evolutionary sense (from a gene-centered perspective) for drones and workers to sacrifice themselves for the good of the Queen. Rockpocket 04:54, 10 July 2006 (UTC)

Although I haven't read The Selfish Gene, Dawkins is exactly who I was thinking of when I wrote my response above. :) --Ginkgo100 ^{talk · contribs · e@} 19:58, 13 July 2006 (UTC)

As stated (finally), onoly honeybee workers have barbed stings - all other bees and wasps (including honeybee queens) that have stings can use them repeatedly. Even yellowjackets, which have very weak barbs, have not yet reached the point where their stings are suicidal, but they're headed in that direction. There is no dilemma, either, as others have noted: if a mutant female who produces sterile daughters ULTIMATELY leaves more fertile offspring as a result of their assistance, then that mutation will spread, as will any mutations that make her daughters more effective at keeping their mother alive and allowing her to produce fertile offspring. It doesn't even require a "gene-centered" model. It's called an evolutionarily stable strategy. Dyanega 02:08, 12 July 2006 (UTC)

[edit] Spinach

How come eating raw spinach makes my teeth feel funny? Does it have some kind of astringent? —Keenan Pepper 20:39, 9 July 2006 (UTC)

Not sure if this is the reason, but spinach does contain oxalic acid. --Ginkgo100 ^{talk · contribs} 20:59, 9 July 2006 (UTC)

Yes, the blame is usually put either directly on oxalic acid which supposedly slightly etches the surface of the teeth, or the gritty texture is attributed to oxalate crystals leaching out of the damaged plant cells. Femto 21:10, 9 July 2006 (UTC)

Cool, I know what that is. Thanks! —Keenan Pepper 21:47, 9 July 2006 (UTC)

So, in a way, it's bad to eat spinach because it etches your teeth? Dismas|^(talk) 01:44, 10 July 2006 (UTC)

Just swallow it without chewing. Or get someone else to chew it for you.  freshofftheufoΓΛĿЌ  05:02, 10 July 2006 (UTC)

Such as a cooking pot. Note he was talking about raw spinach. I'm not sure if that is healthy to eat anyway. DirkvdM 09:01, 10 July 2006 (UTC)

Is this anything like the funny feeling I get on my teeth when I eat a pear? (which is why I don't) DirkvdM 09:01, 10 July 2006 (UTC)

I get that feeling whenever I eat barbed wire. --Dweller 10:17, 10 July 2006 (UTC)

So, for the million dollar question...is the spinach damaging my teeth or helping it? I read that spinach is high in magnesium and magnesium is helpful to tooth enamel.

[edit] sun-oriented structures

i am currently building a labyrinth based on thee design of the labyrinth at chartre cathedral. one aspect of the design is the suggestion by one author, richard "feather" anderson i believe, that the entrance should be oriented to face the rising sun at the summer solstice. i would appreciate help in determining the significance and meaning of the eastern orientation and whether there are other examples.

thank you for your consideration and attention.

bruce haggerstone

As stated in the instructions, please don't put your e-mail address on this page. That's begging for spam. --George 22:45, 9 July 2006 (UTC)