Wikipedia:Reference desk/Archives/Science/2007 December 22

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December 22

Natives and booze

Why didn't natives of North America have fermented alcoholic beverages (except pulque)? It puzzles me because some groups such as the Iroquois had more than adequate supplies of readily fermentable materials like corn and maple syrup. If you've come across any literature on the subject please do point me to it. Thanks! 74.12.208.131 (talk) 00:47, 22 December 2007 (UTC)

The theory I've heard is that nomadic tribes weren't big on alcohol because the long time associated with the distillation process made travelling prohibitive. The agricultural revolution allowed people to settle down and wait for their booze. This is just what I was told by a teacher years ago! (Admittedly, he was a very intelligent teacher whom I respect greatly -- but it wouldn't be the first time someone was misinformed by the public education system.) 99.245.89.152 (talk) 14:59, 22 December 2007 (UTC)

North American Native Americans were mostly agricultural and settled -- at the very least those with corn were. I don't know why fermented alcohol was not used. I know corn is commonly distilled into spirits today, but perhaps it doesn't ferment into something you'd want to drink? I can't recall ever hearing of "corn beer". Pfly (talk) 19:05, 22 December 2007 (UTC)

Corn whiskey. It has to actually be distilled, though, which the native americans might not have known how to do at all. Someguy1221 (talk) 21:24, 22 December 2007 (UTC)

No idea about the North American ones but according to Alcoholic beverage "By the time the Europeans reached the Americas in the 15th century, several native civilizations had developed alcoholic beverages. According to a post-Conquest Aztec document, consumption of the local "wine" (pulque) was generally restricted to religious ceremonies, but freely allowed to those over 70 years old. The natives of South America manufactured a beer-like product from cassava or maize (cauim, chicha), which had to be chewed before fermentation in order to turn the starch into sugars.". It's easily possible there may have been more but a lot of it was lost due to the destruction of large parts of Native American culture after the arrival of the Europeans. Oh and perhaps other stimulants such as coca and tobacco were a substitute for alcohol for some of them? (They also had other stuff like Cacao of course) Nil Einne (talk) 07:57, 23 December 2007 (UTC)

Isn't there some genetic problem with Native Americans and alcohol metabolism? Might this have dissuaded them from routinely producing alcoholic drinks? SteveBaker (talk) 14:19, 24 December 2007 (UTC)

Are you thinking of Alcohol flush reaction? This predominantly occurs in East Asians and after reading the article, isn't that common in Native Americans. In any case when I first thought of this I dismissed it as at best a minor cause at best since it doesn't seem to have stopped the Japanese, Koreans or Chinese from producing alcohol. Nil Einne (talk) 10:57, 25 December 2007 (UTC)

Ok, thanks. If anyone comes across any published work about this please let me know. 74.12.208.131 (talk) 02:06, 25 December 2007 (UTC)

There are some studies that find associative correlations with certain genetic polymorphisms and alcohol dependence in American Indians, such as PMID 12505800, PMID 15274051 and PMID 15722961 but there is nothing mechanistically demonstrated (yet). I don't know for sure, but there may be something of interest to you in Deadly Medicine: Indians and Alcohol in Early America by Peter C. Mancall, Cornell University Press, 1995, ISBN 0801480442. Rockpocket 02:31, 25 December 2007 (UTC)

I can't remember the name at the moment, but the Cherokee had an (admittedly very mildly) alcoholic beverage. IIRC it was made from corn. Vultur (talk) 00:34, 28 December 2007 (UTC)

Appearance of reflected laser light

Some time ago I used a laser interferometer at work to make fine measurements, and recently I've been using a home-grade laser level in some household projects. In both cases I noticed the same thing: Where the light emitted by the laser strikes an object it puts a red spot (or a thin line), but instead of a uniform solid red spot I see what appears like a very finely mottled spot. For example, the laser level is aimed at a wall in my house, so I can affix a shelf to the wall. The spot of laser light isn't a smoothly uniform red spot, but appears mottled or "grainy" in some way. What causes this? 71.112.136.40 (talk) 03:10, 22 December 2007 (UTC)

See speckle. --Trovatore (talk) 03:12, 22 December 2007 (UTC)

LED when it's blown off

What happens when an LED is dead or blown off?..Will it make a short across the line by closing or may it open and give a break in the line?..How do we overcome or predict such problems and be sure about the condition how led's behave?...I often end up with blowing LED or making LED to glow with less intensity by using improper resistance.so please tell me how can we calculate the amount of voltage that the led takes if 'x' resistance is added to it's VCC of say 5V?...Thanks —Preceding unsigned comment added by Balan rajan (talk • contribs) 11:06, 22 December 2007 (UTC)

An LED can short or open. A short will often quickly become an open because of heating. (It's been my experience that they are usually found dead open.) See Light-emitting diode#Failure modes.

A diode will drop a more-or-less fixed voltage once it is forward biased (see Light-emitting diode#Considerations in use). You have to look at the specification sheet for your diode to find out what that voltage is. The specs will also show maximum current. Choose a current near the low end of the range, and calculate a voltage divider with the calculated drop across the resistor at that current and the given drop across the diode at that current. Say the diode drops 1V at 20 ma. The resistor will have to drop 4V at 20 ma, making it 200ohm. I'd put a small linear pot in place of the resistor and crank for desired light output, checking the result against the calculation so as not to stress the diode long-term. Shield your eyes. --Milkbreath (talk) 13:48, 22 December 2007 (UTC)

Adding to Milkbreath's point, LEDs pushed far beyond their ratings will ultimately end up "failed open" because the bond wire that connects the exposed side of the LED chip to the lead frame is a very, very fine wire and it will blow like an electrical fuse. LEDs can also fail shorted, but they can only remain in that state if the rest of the circuitry is still properly limiting the current.

Atlant (talk) 00:29, 24 December 2007 (UTC)

Over here we use the term :'blown up'. blowing off is a completely different thing. --TreeSmiler (talk) 00:56, 25 December 2007 (UTC)

Is Nitreous Oxide for real in automobiles?

We have seen in many racing games like the ones from EA-NFS series which repeatedly introduces the nitreous oxide upgrades for it's cars in the In-game option. So is this nitreous oxide really existing?.If so then how can we get such a boost of power?.Immediate accelaration wouldn't damage the spare parts in the car like the gear shaft or the flywheel for eg?.I have never seen such cars fitted with such things around anywhere here. Also i heard it has the risk of exploding at some circumstances if mishandled. So what is this all about?.... —Preceding unsigned comment added by Balan rajan (talk • contribs) 11:10, 22 December 2007 (UTC)

Our article on nitrous oxide should give you some information. --Ouro (blah blah) 11:42, 22 December 2007 (UTC)

We acutally have a whole article on Nitrous systems. Yes, nitrous can wreak havoc with engine parts - this image shows an engine piston which has been cracked and dented by the pressures created when nitrous is used. When heated, nitrous oxide decomposes to release oxygen, and this extra oxygen allows the fuel to burn harder. It's only used in very high-end racing cars (commonly dragsters, which need all the acceleration they can get), because it is expensive, damages the engine, and most people have no need for the kind of acceleration provided by NO₂ anyway (a turbocharger or supercharger would be far more effective anyway - Nitrous just squeezes the last bits of acceleration out of the fuel). Laïka 12:33, 22 December 2007 (UTC)

Just a nit -- nitrous oxide is N2O, not the far more corrosive NO2. NO2 is a major pollutant and contributor to lung damage; N2O they give you to breathe on purpose (mixed with oxygen of course) at the dentist's office. On the other side of the coin, N2O is explosive under certain conditions. --Trovatore (talk) 23:05, 22 December 2007 (UTC)

Science/Sound waves

Hey Steve, thanks for the reply! I have another question for you- Why is it that the speed of sound is very different in water than what it is in air? Does it have anything to do with the intermolecular forces or intermolecular attraction between the water and air molecules? —Preceding unsigned comment added by GK ROCKS (talk • contribs) 13:46, 22 December 2007 (UTC)

While Steve ain't here for the moment, I can still direct you to our speed of sound article, which has a good introduction, middle part, and ending. --Ouro (blah blah) 14:16, 22 December 2007 (UTC)

What is this insect?

http://i194.photobucket.com/albums/z313/ebmorran/bug.jpg I live in Toronto, Ontario, Canada. We found this (dead) insect in our mailbox today. It's a bit over an inch long. Can anyone tell me what it is? —Preceding unsigned comment added by 99.245.89.152 (talk) 14:57, 22 December 2007 (UTC)

Looks like a Grapevine beetle. There's a good picture here. Matt Deres (talk) 15:31, 22 December 2007 (UTC)

Yup, seems to be it. Thank you! —Preceding unsigned comment added by 99.245.89.152 (talk) 15:42, 22 December 2007 (UTC)

Woo-hoo, my first bug ID! 'course it helps living in SW Ontario... Matt Deres (talk) 17:43, 22 December 2007 (UTC)

Wholemeal bread

Ignoring economies of scale, should wholemeal bread be cheaper to produce than white/brown not-wholemeal bread? --[[User:Seans Potato Business|S[[File:[[File:--223.186.79.214 (talk) 18:07, 16 September 2011 (UTC)Example.jpg

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--223.186.79.214 (talk) 18:07, 16 September 2011 (UTC)--223.186.79.214 (talk) 18:07, 16 September 2011 (UTC)$Insertformulahere$]]]]eans]] Potato Business 14:59, 22 December 2007 (UTC)

The short answer is that that wholemeal bread costs more to make. Here's a more detailed answer below:

Wholemeal is more commonly known as Whole grain. Since we're ignoring economies of scale, I won't figure in the cost difference between whole wheat and bleached, or other type of wheat flour. The process of making bleached flour is more expensive than to make whole wheat, due but due to its greater demand, bleached flour is cheaper to buy. And additionally whole grain flour is more expensive to store, due to it being susceptible to Rancidification. But we won't factor that extra cost in for this question.

It is actually simpler to make bread from flour that has been processed (such as bleached flour) than whole wheat flour. This is due to the fact that the whole wheat flour contains a lot of Cellulose (sometimes called Dietary fiber) from the outer shell of the wheat kernel. This prevents much of the inner starchy Endosperm to be easily broken down during the process of making the bread dough. In white bread this is not a problem, since all of the dietary fiber has been removed, making it so that the dough is more quickly turned into a form in which it can be ready for baking.

Besides the cellulose issue, there's also the issue concerning Gluten content. Gluten is the protein found in many grains, and it is what makes bread dough "sticky" when it is kneaded. The kneading process breaks the flour particles down, releasing the gluten protein from within the wheat flour particles, and then as the protein molecules start adhering to each other, this produces the stickiness. The more gluten present in bread dough, the stickier it is. When it is baked, this stickiness will be what binds the bread together, creating a firm loaf with pleasing texture for the typical human palate. Different types of wheat flour have different levels of gluten present. It depends on what kind of wheat one is using, as well as additional factors that are described in the article on Flour.

If you've ever eaten whole wheat bread that is dry, crumbly, and texturally unappealing, it is because it was prepared in such a way that the cellulose was not broken down in the dough, and/or there was not enough gluten present before it was placed into the oven to bake. This is the biggest reason that whole wheat bread is not as popular as white - it takes more preparation to make it as appealing to the palate of the typical consumer.

So, how does one take whole wheat flour and make it so that the cellulose is broken down, thus creating better quality bread? There are several considerations to take into account. First, you have to have good quality whole wheat flour. By that I mean, it must be considered to be at least as good as "bread flour", which contains at least 11% gluten. To achieve this, the flour must come from a high-gluten wheat, it must be ground in a mill that will break down the cellulose to a very fine texture, and the dough must be properly prepared to allow further breaking down of the flour to allow the gluten to be able to be freed when it is kneaded.

This last step is important. The best way to prepare whole wheat bread is to combine all the ingredients - except the yeast - and then to allow the dough to sit for at least 24 hours before adding the yeast and preparing it for baking. This 24 hour period allows the cellulose to be broken down further, releasing the gluten. When the dough is first made, it should be mixed and kneaded, and then as it sits, it should be kneaded every 8 hours. This also helps the breakdown process. After the 24 hours is up, bring the dough to a temperature that will optimize yeast growth (30° - 37° C, or 86° - 99° F), add the yeast mixture (yeast, water and sugar, which has been allowed to "start"), and then knead the leavened dough two or three more times before baking.

There are plenty of bakeries who try to short-cut this process, and you can immediately tell by sampling their product that they produce an inferior quality whole wheat bread. A good quality loaf of whole wheat will be firm, moist and have a nice flaky crust - however, it will never be possible to achieve the same level of quality as a very good white bread loaf. That's the trade-off of good health, I suppose. Now, as to how much all these extra steps will cost, I'll leave that to you to figure out. I will, though, include a recipe that I have used myself to make quite good loaves that I sold to customers when I did this sort of thing:

Whole Wheat Bread (three 2-pound or four 1.5-pound loaves)
12 cups unsifted whole wheat flour
1/2 cup raw sugar, honey or molasses
1/3 cup cooking oil or melted shortening
2 Tablespoons salt
5 to 6 cups milk or potato water - if fresh (raw) milk is used, scald first)
2 packages (Tablespoons) of bakers yeast
1 teaspoon sugar

Mix well and let stand overnight 24 hours, kneading every 8 hours, at room temperature. Bring the dough up to a temperature of around 90° F (you can place it in the oven with the setting on Warm). When the dough is warm, mix the yeast and sugar into one cup of water that is between 86° - 99° F and allow it to rest undisturbed in a warm place for about 10 minutes until the yeast begins to work (it will be frothy). Add the yeast to the dough and knead. Allow it to rest for 10 minutes. Now the dough must be kneaded constantly for at least 10 minutes. Do not add flour during the kneading process, even though the dough will become very sticky and almost soupy. If kneading by hand grease may be added a couple of times to the kneading board and one's hands, but not flour. Put the dough back in a covered pan and set in oven to rise at a temperature of 80° to 85° F for one hour, or until it doubles in bulk. Remove the dough and knead constantly for another 10 minutes. Divide the dough into loaves, but let it rest while you grease the baking pans. Shape the loaves so that you tuck the ends in neatly and then lay the loaf into the pan so that the fold of the dough is on the bottom. Lightly grease the top of the loaf with shortening or margarine (not butter, as it will dissipate). Set the loaves in the warmed oven to rise for 15 to 20 minutes at 80° to 85° to allow them to rise to not quite double. Then raise the temperature of the oven to 325° and bake for 70 to 80 minutes. I used to add a cup of coarsely ground (cracked) soy beans to the dough, which gave the bread an added texture, and provided addictional amino acids for people who were vegetarians. If done right, the end product of this recipe will produce nice, firm, moist loaves. -- Saukkomies 07:50, 23 December 2007 (UTC)

two slits, QED and light

I'm trying to write a gentle math-less explanation of quantum electrodynamics (or quantum field theory, somewhere in between really, it's mainly based on Feynman's QED book). The problem is, I'm doing so after a series of lectures that were just as gentle and light on mathematics, so I may understand certain things, but I don't have the rigorous education required to know for sure whether my intuitive understanding is actually correct. Since I do need to write about it, I'd like to ask you if I've understood the basic ideas.

As I understand it a photon traveling from A to B does so, not in a straight line, but along all paths (each with an associated probability amplitude). These amplitudes can be represented as arrows, where the length of each arrow is (about) equal, and it's the angle of the arrow that increases as the length of the path increases (I think this is Feynman's way of saying that amplitudes are represented by complex numbers, right?). I understand how this means that paths in a small neighbourhood far away from the shortest path cancel each other out, whereas paths in the neighbourhood around the shortest do not, as much, and therefore the closer a path is to the shortest path, the more it contributes to the probability function of the foton's location, which thus becomes essentially a sharp peak along the shortest line from A to B. I also understand that when the foton passes through a narrow enough slit, the probability function on the other side of the slit will spread out like a handfan (mimicing a wave passing through a slit).

The thing I'm uncertain about, and that I would like to see affirmed is the reason for the wave character of the probability function/wave function. If I want to explain the double-slit experiment in these terms, it isn't enough that the slits spread the wave function out, the peaks of the waves also need to come from somewhere. The way I understand it now, is that as the paths I talked about earlier are lines in spacetime, not just the path of the foton varies slightly around the shortest path, the speed of the foton also varies slightly around the shortest path in space-time, ie. the maximum speed. Each foton has a small probability of traveling a bit faster than lightspeed or traveling a bit slower, just like they have a small probability of deviating slightly from the shortest path (so far I'm just paraphrasing Feynman). This makes the probability function of the foton a tiny blob around the point that travels in a straight line at lightspeed, or a fuzzy circle, spreading out, if we don't know where the photon ends up. Is it this 'blob' that creates the peaks in the probability function, that corresponds to the peaks in EM waves in the classical model?

Is there anything to criticize about this view of things (feel free to nitpick, I can always add footnotes, to say I cheated a bit to simplify). risk (talk) 19:08, 22 December 2007 (UTC)

The first thing to understand about the path-integral approach to wave mechanics (the one where you have a particle taking all possible paths) is that it's not specific to quantum mechanics. You can formulate classical wave theories (linear ones, at least) in the same terms. With the exception of the use of the word "photon", what you've written above is essentially classical, and a good part of QED (the book) is classical as well, including the whole discussion of reflection, refraction and diffraction. A photon taking all possible paths doesn't just mimic a wave, it is a wave. I think Feynman comes on way too strong with the claim that light is made of particles and not waves.

The path-integral approach has advantages and disadvantages over the wave-equation approach, and one of the disadvantages is that it's not easy to see where the wave-like behavior comes from. One way to understand the connection is to think about triple, quadruple, quintuple... slit experiments, and how you'd calculate the pattern on the screen. It should be obvious that you just add contributions from each slit. Now add a second barrier in front of the first one, and put slits in that as well; now you have to add contributions from every pair of slits in the two screens (a total of nm terms if there are n slits in one screen and m in the other). As the number of barriers and the number of slits goes to infinity, the barriers effectively disappear, and the pattern on the screen is a sum of terms for every possible path between the source and the screen. -- BenRG (talk) 21:06, 22 December 2007 (UTC)

parkinison's disease [specifically dyskinesia ]

Medical question removed

You should consult her doctor about this problem, as the reference desk guidelines prohibit us from offering medical advice. Someguy1221 (talk) 21:48, 22 December 2007 (UTC)

radioactive decay

Quote: "Thus, the number of nucleons modulo 4 is preserved across any decay chain." - what does that mean? Is the word modulo being used correctly? Checked the modulo page but still don't understand this sentence. --Seans Potato Business 22:17, 22 December 2007 (UTC)

It just means except for differences of whole number multiples of 4, the number of nucleons is maintained throughout a decay chain. I haven't looked at the disambig page, but it satisfies Merriam-Webster's (2000 edition) definition of modulus (1 c) "the number (as a positive integer) or other mathematical entity (as a polynomial) in a congruence that divides the difference of the two congruent members without leaving a remainder" It's certainly a more concise way of putting it, if not the most easily understandable. Someguy1221 (talk) 22:23, 22 December 2007 (UTC)

And funnily enough, it just hit me that it's completely and utterly incorrect, as radioactive nuclei can emit individual protons, neutrons, or whole other nuclei. Someguy1221 (talk) 22:36, 22 December 2007 (UTC)

Yes, but the nuclei that decay by those processes all have tiny half-lives, so they never occur naturally. All natural decay chains obey the mod 4 rule. —Keenan Pepper 19:30, 23 December 2007 (UTC)

Except spontaneous fission, that is. Other than SF, the longest half-life of any modulo-4-changing decay is bromine-88, which has a half-life of 16 seconds and a 7% beta-delayed neutron emission branch. —Keenan Pepper 19:56, 23 December 2007 (UTC)

Cystus

Cystus: Is there another name for this garden flower, please? Vernon White ^{. . . Talk} 23:16, 22 December 2007 (UTC)

Do you mean Cytisus? --Heron (talk) 23:21, 22 December 2007 (UTC)

I think it is German for Cistus. DuncanHill (talk) 00:58, 23 December 2007 (UTC)

Thanks for this. Yes meant "Cistus". The old British text I was quoting used "Cystus". Vernon White ^{. . . Talk} 20:28, 23 December 2007 (UTC)

What species of bird is this?

I found this little guy sitting on a wire fence on the side of Mount Albert, Auckland, and I was wondering what species of bird he was. I want to say swallow, but I'm probably wrong and I'd like to be sure. Thank you! 211.30.58.79 (talk) 23:55, 22 December 2007 (UTC)

I'm not familiar with the birds of New Zealand, but that's definitely a swallow. My guess is welcome swallow. Matt Deres (talk) 02:35, 23 December 2007 (UTC)

I tried a full search where plenty of people put plenty of pics and tag them : flickr "http://www.flickr.com/search/?w=all&q=New+Zealand+swallow&m=text". See for yourself!-- DLL ^{.. T} 11:12, 24 December 2007 (UTC)

Memories from young age

Is there a limit to how far back one can remember in their life? I have a memory that I'm sure is not false that occurred when I was 1 and half, is that farther back than normal? Imaninjapirate^{talk to me} 23:59, 22 December 2007 (UTC)

It would very from person to person, but it typically somewhere between 1 and 2, probably more towards the 2 end. Until a certain point, a child does not distinguish between him/herself and everything he/she can perceive that is not him/herself. It's only when that realisation dawns that memories of the "outside world" start being collected. It's quite possible to have a memory from the age of one and a half, although most people don't. -- JackofOz (talk) 00:22, 23 December 2007 (UTC)

Haven't there been some wierd psychological theories on "memories from the womb" having some significance? Seems utterly silly to me, but...Someguy1221 (talk) 00:31, 23 December 2007 (UTC)

I can believe that verbal coding is the key to retrieving most memories, so the acquisition of language would therefore limit the reach. Persons who are advocates of Repressed memory speak of "body memories;" not sure what they are. I have heard people tell of memories of persons or places which would place the memory before age 2, while others say nothingcan be remembered before age 5 or 6. Might have to do with verbal intelligence. Animals (specifically elephants and pigeons) have demonstrated long term memories, so words are not always necessary. I certainly believe adults could remember things from age 1 1/2 years, but experiments have shown that memories are suggestible: college students could be convinced they remembered seeing a Donald Duck costumed character in a visit to Disneyland, but no such character ever appeared there. I have very clear memories from age 3, and more vague ones dating back to a time when the age or date was not clear, but was very likely before 2. Edison (talk) 01:11, 23 December 2007 (UTC)

(Fixed your link. --Anon, 04:37 UTC, December 23.)

Hi. I think I have memories from, like, a few months after birth, however I'm not going to describe them in detail because I consider it personal info. Anyway, I have far more memories from say, when i was 1 or 2 than from when I was 0. However, most of the memories have rusted, and for some of the memories as much as half or maybe all of it is false. For example, one memory that I think may be false was when I supposedly saw Jupiter and Saturn closely in the sky as big and bright as the full moon. That's next to impossible. I have other memories of going to bed, doing math, reading a book, looking in the mirror, watching TV, eating, talking, etc, from as far back as 3 or 2 or even 1. However, I don't think a lot of people would be able to recall their actual birth for various reasons. I think that memories may be partially the result or one's parents telling them about when they were little, thus adding supposedly "memorised" detail to the memory. I think it helps when you're trying to recall long-ago memories if you have a photographic memory. Some people even claim to have memories of previous lives, although there isn't really any real proof. I even remeber some of my actual dreams from my early childhood, but only in vague detail. As you age, it is easier to forget your memories of early childhood, as they rust more and more. Hope this helps. Thanks. ~AH1^(TCU) 01:56, 23 December 2007 (UTC)

It's not in his page, but ISTR Isaac Asimov claiming to remember his own circumcision. My own memories don't go back before about the age of about two, but I know several people who have no recollection of their own childhood, so there's obviously a lot of latitude from person to person. For my own part, I see no reason why our memories could not stretch back to within the womb at least theoretically or (more likely) from birth - our brains are designed to retain knowledge after all. Consider this - a child of two has already memorized several words and phrases, even if they cannot articulate them as speech; obviously their noggins are already soaking up memories of some kind. Matt Deres (talk) 02:52, 23 December 2007 (UTC)

Isaac Asimov described his earliest memory when he was about 59; like most of the others mentioned here, it was from when he was 2 years old, not a few days. This is in Chapter 4, Section 2, of In Memory Yet Green.

I have only one memory of this early period of my life. It is the vague impression of a book. I recall sitting in a chair, turning the pages of a book, and loving it. Then I seem to recall wanting the book again, and looking about for it vaguely, but not finding it and wondering where it was.

Years later, I told this to my mother in an effort to place the memory and she said, "I remember the book. You were two years old at the time and you loved it."

I said, "But where did it go? I remember turning the pages and then I couldn't find it."

"Sure," she said, "because every page you turned you tore out."

--Anonymous Asimov fan, 04:37 UTC, December 23, 2007.

I have a memory from when I was probably around 18 months old. I know this because my father was in the Air Force and we moved around a lot when I was little, so that the details of my memory describe a place where we lived between when I was 12 months to 18 months old (my mother verified the details of this later). The memory was of laying in a crib in a room with an open window, looking out to a back yard and a forest beyond. No real events took place - it was just the impression of the place. -- Saukkomies 08:00, 23 December 2007 (UTC)

The memory I have is from a few different times on one day. I was ,according to my mom about 1 and a half, and I first remember the lady at the daycare telling me to put away a toy truck, but I ignored her. We then went for a walk on bike tracks outside the daycare and I all of a sudden saw my dad. He was working on building some new road. I suppose I remember this because it was the first time I found out my parents had a life outside of my house. Imaninjapirate^{talk to me} 17:20, 23 December 2007 (UTC)

My earliest memory: I was lying in my cot one night. I decided to push my eiderdown off to feel what the cold was like (although I'm doubtful I reasoned all this out in words - and I should explain this was in an unheated room in the 1950s). I must have fallen asleep, because when I woke up again later that night I was warm. Someone had put the eiderdown back over me while I slept. 80.0.124.1 (talk) 23:36, 23 December 2007 (UTC)

What you say about a general recollection, but not specific, of something is where I think one needs to look, too, when considering earliest memory. My earliest memory of a specific event of several minutes in length, not just a "snapshot," which I know when it happened was when I was 6 - I'd gotten my first hearing aid shortly before, and we were on vacation in Florida. I heard the squawking seagulls from the bathroom window of our motel, and I asked my mom excitely why the birds were so close!

But, I can recall general thingswalking around the block to my great-grandmas, a story I made up about one stuffed dog with a pattern of flowers on his back (rolling in a flwoerbed on the way there), and so on, from well before then. I even baguely recall my great grandpa, the husband of the one who lived near us, who died when I was 3 and a few months. However, that may be tied to my mom telling me about him or looking through pictures.

I think the one at 6 shows the ability to grasp an entire scene and all that is going on, and describe it in pretty good detail. That may vary from person to person, but I dont' think it comes till a bit later, like 4-7. Other memories may be snapshots - the story I made up about the stuffed dog, or yours about the truck - but without much background. Others may be generalities that I recall becuase they "often happened" and are recorded in there because nothing of major import occurred, but the repetition ingrained them.Somebody or his brother (talk) 01:22, 24 December 2007 (UTC)

My earliest definitely datable memory is my 4th birthday. But like John Prine said, "often remembered / so many times that my memories are worn" — I suspect that most of my early memories by now are really memories of remembering and telling of those early events. I have many holes in memory of events, even of my teens. —Tamfang (talk) 03:42, 24 December 2007 (UTC)