Wikipedia:Reference desk/Archives/Science/2013 January 26

= January 26 =

Opel truck
What's the maximum number of people that can squeeze into an Opel Blitz truck? Thanks in advance! 24.23.196.85 (talk) 01:38, 26 January 2013 (UTC)


 * The German article (de:Opel_Blitz) has technical specifications, including maximum weight, and sizes, for various truck models. Those should help you set some reasonable bounds.  Nimur (talk) 01:45, 26 January 2013 (UTC)


 * It has no specs for any of the WW2 models -- and those are the ones I want to know about. 24.23.196.85 (talk) 02:03, 26 January 2013 (UTC)


 * If you're wondering about the ability to move soldiers in WWII, the answer is "how desperate are you?". If you're not worried about things like "safety" or "keeping the truck working next week", you can fit a rather incredible number of people on one truck.  On the other hand, for routine operations, a good rule of thumb is that one truck can carry one squad of soldiers with full equipment. --Carnildo (talk) 02:17, 26 January 2013 (UTC)


 * Thanks! And would 12 soldiers be a squad?  The article says it would be. 24.23.196.85 (talk) 03:42, 26 January 2013 (UTC)
 * Its supply carrying capacity is more important than its infantry carrying capacity. 3 tons. There are space for 10 seated facing each other in the back, from seeing one.--89.101.197.30 (talk) 14:25, 26 January 2013 (UTC)


 * Echoing 89's comment, supply capacity really is a far more interesting number than troop capacity. The WW2 German Army was, on the whole, very poorly mechanized.  Our Horses in WW2 article notes that a standard German infantry division had about 250 trucks (and 2,500 horses) for about 20,000 troops.  While you can put troops in those trucks, you obviously can't put anywhere near all of them in, and that leaves your division moving at foot speed -- de-emphasizing the troop-carrying capabilities of the truck.  The Panzergrenadier divisions were well-mechanized (and far more closely resembled the majority of British and American infantry units in that regard), but there weren't many of them. &mdash; Lomn 15:54, 26 January 2013 (UTC)


 * For me personally, troop-carrying capacity is more interesting -- my actual question was whether a total of 12 French Resistance fighters could fit into an Opel Blitz, and whether there would be any room left for a few concentration camp escapees to share space with the dozen Maquis on board. 24.23.196.85 (talk) 04:55, 27 January 2013 (UTC)


 * I'm sure that in an extreme need, you could fit that many people into the truck. It wouldn't be comfortable - but it's clearly possible.  The thing about vehicles of that era is that they typically had very low horsepower compared to modern vehicles.  That German article says that the 1945 version produced 73.5 hp and weighed 5,500lb.  Compare that to a comparably heavy, modern Ford Explorer (280hp, 5,000lb!) - and you can see that despite weighing a little more, the 1945 Opel has less than a quarter of the power-to-weight ratio of a modern 'people carrier'.  Put 15 guys in there (let's say 150lb each - maybe 200lb with weapons & packs...3,000lb total) and the truck now has maybe a sixth of the power-to-weight of a modern truck.  The German wikipedia article says it has a maximum payload of 7,200lb - so the frame and suspension could easily manage even 30 people.  Of course your Opel must be a yet older model - so I'd expect similar weight but even less horsepower...but it would be nice to know those two figures to be sure.


 * But with such an awful power-to-weight ratio, instead of 0-60mph in 12 seconds(ish) in an Explorer - your acceleration in a heavily loaded 1945 Opel is going to be 6 times worse! In reality, it wouldn't ever reach 60mph - but if it could, it would take a minute and a quarter with foot mashed to floor to get there!  So what would happen would be that the thing would have very poor performance - you'd probably have to drive it in a lower gear, keep your speed around 30mph and go up hills at walking pace in 1st gear - and you might have to have the guys get out and push on a really steep road...but that's how trucks were driven back then.   But in low gear, I'm sure it could manage.  If the people would physically fit in there - I'm sure it would carry them OK.  In times of great pressure, I'm sure our brave Maquis would be happy to hang on the outside - lay on the roof, etc.  SteveBaker (talk) 16:21, 27 January 2013 (UTC)
 * You can seat two guys in the cab, ten in rear seats, and anyone else has to squaton the floor between the seats in the back. Of course, at slow speed, you could cram 20+ guys in the back, three or four in the cab and 10+ hanging on to the outside. There are some funny world war ii pictures of this type of thing around.--89.101.197.30 (talk) 20:54, 27 January 2013 (UTC)
 * So, 20-25 people would fit in just fine, at the expense of greatly reduced speed and acceleration (which is fine by me, and can actually help to build dramatic tension) -- is that right? 24.23.196.85 (talk) 00:41, 28 January 2013 (UTC)
 * It the 1945 truck specifications aren't too different from the pre-1945 version, then yes. To be clear about the performance thing: On a smooth, level road, top speed is determined overwhelmingly by atmospheric drag...but acceleration is all about mass - so in the best conditions, the overloaded truck might be able to get up to a reasonable speed eventually.  However, on a rough road or when going uphill, the mass is again important.  Another thought is that those old vehicles had really bad brakes - and deceleration (just like acceleration) is determined mostly by the amount of weight it's hauling around.  So if you ever did get it going fast, it would be really poor at braking.  If you make the thing too top-heavy, there might also be a roll-over risk when cornering hard...the ability to corner fast also depends greatly on the weight of the thing.  SteveBaker (talk) 13:08, 28 January 2013 (UTC)
 * Thanks, I'll keep all this in mind. FYI, the scene I have in mind takes place during an escape from Natzweiler-Struthof, and I'm pretty familiar with the terrain there -- the ground rises quite a bit when going away from the camp (with a corresponding fall on the other side of the hill), and the road is quite winding, though the terrain does level off farther out.  So all these factors can make the difference between getting away clean or crashing and getting recaptured -- perfect for my purposes (bwahahahaha!) 24.23.196.85 (talk) 06:00, 29 January 2013 (UTC)

Nutrition facts of cooked chicken
Wikipedia article on Chicken (food) and Nutritiondata have different data. Our article says 100 g of cooked chicken contain 26 g protein, Nutritiondata says the figure is 31 g. From where will I get a reliable and accurate nutrition information? --PlanetEditor (talk) 04:48, 26 January 2013 (UTC)


 * Those are close enough that both could be in the normal range. The breed of chicken, how the chicken is raised and cooked, whether it's white meat or dark, whether the skin is removed, etc., could all account for the difference. StuRat (talk) 05:03, 26 January 2013 (UTC)


 * What StuRat said. Checking the website that is the source for the data in the Wikipedia article has hundreds of different variations on cooked chicken, and it isn't readily apparent which specific entry the Wikipedia data is drawn from, but given the variation likely, it doesn't seem impossible that both sets of data are correct, for any given value of "chicken".  -- Jayron  32  05:07, 26 January 2013 (UTC)


 * Not to mention that two chickens will not necessarily be identical, so the amount of protein in them would be different (for example, if you were more muscular than I, you'd likely have more protein). Those numbers are from different sources, which likely took the mean of the protein content of many chickens, so if different chickens were used to calculate the numbers, you'd get different values.  Bramble  claw  x   05:09, 26 January 2013 (UTC)


 * the nutritiondata page specifies Chicken, broilers or fryers, breast, meat only, cooked, roasted, the usda page which is the source for the wikipedia table says 28.93 gm for Chicken, broilers or fryers, meat only, roasted; that reduces the difference to 7% (don't know which particular chicken entry of the multiple varieties given in the usda page was the source for the 26). Considering that the nutritiondata number is only precise to 0 decimal points, i.e. 3%.... as we used to say in biology lab, "within 10% means it's the same". Gzuckier (talk) 07:32, 26 January 2013 (UTC)


 * Here's an entry from NutritionData.com which seems to match our Wikipedia article: . However, our article giving the protein value down to .01 gram seems a bit silly.  Perhaps technical limitations prevent rounding different nutrients differently in the same table, or they just thought everything should be rounded the same as a style issue. StuRat (talk) 05:17, 26 January 2013 (UTC)


 * Thanks everyone. Another question, which part of chicken contains maximum amount of protein? --PlanetEditor (talk) 05:31, 26 January 2013 (UTC)


 * I'm going to guess that also varies by chicken. The obvious answer is "the muscles" (which have lots of the proteins actin and myosin) as opposed to "the bones" which are made largely of calcium phosphate and collagen (which I suppose is also a protein).  Bramble  claw  x   05:35, 26 January 2013 (UTC)


 * Looking through the NutritionData.com charts, it looks like the breast. I'd guess that's because other parts, like the back, wings and thighs, contain a larger percentage, by weight, of bone.  They probably should compare the various pieces without the bones, to remove this bias. StuRat (talk) 05:54, 26 January 2013 (UTC)


 * Not just formed by bone, but indeed chicken wings, thighs, and legs, all contain a significantly higher proportion of fat (in the edible parts) than chicken breast. Source - those nutrition labels they force them to stick on the packages in the UK. Whether the difference is made up mostly by protein or not, I wouldn't say for certain, but I would guess it's likely. --Demiurge1000 (talk) 06:22, 26 January 2013 (UTC)


 * It says 64 grams of cooked chicken is water. Slight differences in meat dryness probably change protein per 100 g alot. Also, don't go overboard with the protein eating, it is possible to eat too much. Sagittarian Milky Way (talk) 03:53, 28 January 2013 (UTC)

Rain = snow depth
What would be the equivalent snow depth of 2 inches of rain? In other words, if 2 inches of rain fell as snow, how deep would the snow be? --TammyMoet (talk) 17:31, 26 January 2013 (UTC)


 * It depends on how wet/dry the snow is. 10 inches of snow to 1 inch of water is the common rough estimate. &mdash; Lomn 17:41, 26 January 2013 (UTC)


 * (ec) As noted in snow gauge, the 'rule of thumb' ratio often used in comparing rainfall to snowfall is 1:10&mdash;that is, one inch of rain is roughly the same amount of precipitation as ten inches of snow. (In reality, however, a whole bunch of ambient factors affect the density of snow.  3 to 5 inches of really dense, 'wet' snow may melt down to an inch of water, whereas it might take 30 or more inches of really light, fluffy snow.) TenOfAllTrades(talk) 17:43, 26 January 2013 (UTC)


 * Also note that snow compresses after it falls. So, it will become steadily more dense, the longer it sits on the ground, eventually becoming ice, with almost the same density as water.  This is especially true of snow which is compressed by the weight of snow above it, or where people or cars pass above it. StuRat (talk) 17:53, 26 January 2013 (UTC)


 * Cold snow is drier, due to absolute humidity. Sagittarian Milky Way (talk) 18:14, 26 January 2013 (UTC)

Thank you all! (Currently breathing a sigh of relief that the rain we had last night wasn't snow.) --TammyMoet (talk) 20:08, 26 January 2013 (UTC)


 * Note that you generally get far less moisture falling as snow than as rain, since you only get snow when it's cold, and cold air holds much less moisture to begin with. However, the snow might seem like more, both because it takes up more room, and because it sticks around, versus rain which usually goes down the nearest drain, soaks into the ground, or evaporates, in short order.   StuRat (talk) 20:31, 26 January 2013 (UTC)


 * See Snow which has some references. And no, snow, of a single season, does not become ice. Snow that does not melt in the summer may eventually turn into glaciers. If the snow has become ice in a single season then it is due to partial melting and later refreezing. CambridgeBayWeather (talk) 19:14, 27 January 2013 (UTC)


 * You apparently haven't seen a road after cars have driven over snow a few days. Solid ice results, unless salt is used. StuRat (talk) 04:50, 28 January 2013 (UTC)


 * In fact, during the Battle of the Bulge, it only took one day of tanks driving over snow-covered roads to turn the snow into ice -- despite constant plowing, salting, etc. 24.23.196.85 (talk) 07:12, 28 January 2013 (UTC)
 * In my immediate experience ten days ago (on the South coast of England), a day of lighter-than-usual pedestrian traffic on town pavements ('sidewalks') can be sufficient to turn 3 or so inches of snow into uneven ice. I walked most of 5 miles into work (buses and other vehicles proving unable to cope on inclines) in the near-virgin snow quite easily, but walking a mile to the railway station that evening was far more difficult. {The poster formerly known as 87.81.230.195} 84.21.143.150 (talk) 14:45, 28 January 2013 (UTC)


 * I'm talking about paved roads in Yellowkinfe after months of vehicles passing over them. CambridgeBayWeather (talk) 14:47, 28 January 2013 (UTC)


 * Perhaps the low temperatures in Yellowknife prevent the snow from melting and refreezing as tires compress it, and thus delay ice formation there. StuRat (talk) 07:54, 29 January 2013 (UTC)

Formal term for re-mapping of a set of values to other values.
Hi,

Please help me find the above technical term.

Quantisation is the proces of remapping values to a smaller set of values (many-to-few), but what is the term where the number of values in the set remain the same, but the data points change value? (edited, sorry the following is an example of the sought after term, not quantisation, so the example is:)

There data points at the start are: 1, 3, 5, 7, 9. Some of the data points values are changed by some algorthym or process, or so that they align with some other value set, and the resultant values are 1.5, 3, 5, 6, 8 respectively.

This is not quantisation, as the number of data points has not been reduced. Only the values of each data point have been realigned to a new set of values.

What term could describe this?

Thanks, Dale. — Preceding unsigned comment added by Califauna (talk • contribs) 20:16, 26 January 2013 (UTC)


 * Not an an answer, but the first case, where you remap data to a smaller set, is known as "hashing", at least in computer science. In the second case, I'd simply call it "remapping".  StuRat (talk) 20:27, 26 January 2013 (UTC)


 * In mathematics this sounds like a function. Ulflund (talk) 22:01, 26 January 2013 (UTC)


 * Yes, although when applied to data points I think the term transformation is more widely used. Looie496 (talk) 01:03, 27 January 2013 (UTC)

Thanks for the above. All excellent. — Preceding unsigned comment added by Califauna (talk • contribs) 03:58, 27 January 2013 (UTC)