Wikipedia:Reference desk/Archives/Science/2016 August 31

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

August 31

What fruit or vegetable is the healthiest?

Ie: widest range of vitamins and minerals or other things available. JoshMuirWikipedia (talk) 09:55, 31 August 2016 (UTC)

Kale - according to this scoring system. http://d3n8a8pro7vhmx.cloudfront.net/foodday/pages/8873/attachments/original/1393950515/Vegetable_Ranking.pdf?1393950515 Wymspen (talk) 10:22, 31 August 2016 (UTC)

It's going to depend very much on how you score things. For example, while high in micronutrients, kale lacks much in the way of the macronutrients fat and protein, which are dietary requirements, so would not be a good choice as a sole food. Avocados contain fat, but not much more protein. Protein is difficult to find in fruits and veggies, but perhaps edamame (immature soybeans) might qualify as a "vegetable", and it also contains some fat. Also, if one fruit or veggie was your sole source of nutrition, you might even suffer from a sodium deficiency, unless you ate something like edible seaweed, that contains salt. So, the inevitable conclusion is that no one fruit or veggie is sufficient alone. StuRat (talk) 13:05, 31 August 2016 (UTC)

That's interesting, I was just reading the other day about Bowman–Birk protease inhibitor, an anti nutrient found in soybeans which prevents absorption of proteins. This is what inspired the question, as I was wondering if there were any systems taking into account these factors. JoshMuirWikipedia (talk) 12:54, 1 September 2016 (UTC)

If you consider turnips, along with its "greens", you get a much better balance of nutrition (than kale), especially in regard to essential amino acids:[1] 2606:A000:4C0C:E200:F853:9A57:8459:1F05 2606:A000:4C0C:E200:F853:9A57:8459:1F05 (talk) 19:48, 31 August 2016 (UTC)

What automobile is the best? --47.138.165.200 (talk) 20:48, 31 August 2016 (UTC)

For hauling fruits and vegetables? ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:39, 31 August 2016 (UTC)

I always thought it was bananas for some reason, but I don't believe any fruit is a complete food. I've also read several times that kimchi is rated as "the healthiest food" but while it's mostly cabbage, it's not "unprocessed" vegetable. Vespine (talk) 23:25, 31 August 2016 (UTC)

Healthy but stinky and looks like blood with vegetable pieces in it. It must be an acquired taste. Sagittarian Milky Way (talk) 00:26, 1 September 2016 (UTC)

Like sauerkraut only a lot worse? ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:15, 1 September 2016 (UTC)

Sauerkraut is often placed among the wurst. StuRat (talk) 01:23, 1 September 2016 (UTC)

And the boy wins a cigar! ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:34, 1 September 2016 (UTC)

Sturat, usually your puns just make me groan, but I will give you this one, very good!. Did you pay Bugs for the setup? ;) I grew up eating sourkraut (and bigos which is literally wurst among sauerkraut) and love some good kimchi, I've never heard it described as resembling "blood". Vespine (talk) 01:35, 1 September 2016 (UTC)

See "Overall Nutritional Quality Index".—Wavelength (talk) 00:36, 1 September 2016 (UTC)

• Milo Yiannopoulos appears very healthy; although he's admittedly dangerous. But as he's not running for president, we can't say. μηδείς (talk) 21:36, 1 September 2016 (UTC)

Plus, I should clarify, he does not identify as a vegetable. μηδείς (talk) 21:41, 1 September 2016 (UTC)

Q: Why doesn't Elton John eat kale?
A: Because he's a rocket man.
--Shirt58 (talk) 04:16, 4 September 2016 (UTC)

Enthalpy of nuclear reactions

Nuclear binding energy of common nuclides: ⁵⁶Fe is marked out specifically. (⁵⁸Fe and ⁶²Ni have marginally higher binding energies but are not produced in large quantities in stellar nucleosynthesis, unlike ⁵⁶Fe.) Double sharp (talk) 06:14, 1 September 2016 (UTC)

How does the the concept of enthalpy of reaction apply to the case of nuclear reactions? What specific aspects occur in this case compared to chemical reactions?--82.137.11.210 (talk) 19:09, 31 August 2016 (UTC)

Small atoms tend to give off energy when combined into larger atoms, up to a point (for example, hydrogen combines to create helium in the Sun). See nuclear fusion. Large atoms, on the other hand, tend to give off energy when they split up, such as radioactive isotopes of uranium, etc. See nuclear fission. Somewhere in the middle, say around lead, you get rather stable atoms which are at the lowest nuclear energy state. StuRat (talk) 19:25, 31 August 2016 (UTC)

The nuclear analogy for bond dissociation energy (which can be used to calculate the enthalpy of chemical reactions) is nuclear binding energy--Jayron32 20:32, 31 August 2016 (UTC)

The middle is hardly at lead. Iron would be far more accurate, with an "iron peak" in the middle of the first-row transition metals of very stable nuclides. Double sharp (talk) 06:12, 1 September 2016 (UTC)

Lead is actually the heaviest element whose radioactive decay has not yet been observed experimentally. (following observations of slow decay of bismuth) See isotopes of lead; it is believed to undergo decay with an extremely long half-life. Wnt (talk) 22:15, 1 September 2016 (UTC)

Better yet, check the footnotes in lead. Calculations suggest that the half-life of ²⁰⁷Pb cannot be lower than about 10¹⁵² years, and is probably longer. (The lower limits of orders of magnitude for the other isotopes are 10³⁵ years for ²⁰⁴Pb, 10⁶⁵ years for ²⁰⁶Pb, and 10¹²⁴ years for ²⁰⁸Pb.) Evidently, there is no hope in observing this decay now. Double sharp (talk) 04:21, 4 September 2016 (UTC)

See Wikt:middle. I was using def 2: "The part between the beginning and the end", not the exact midpoint. That's why I said "Somewhere in the middle", as opposed to "exactly in the middle". StuRat (talk) 17:13, 2 September 2016 (UTC)

Iron is generally regarded as being at the peak binding energy among elements. Lead, however, is so not-prone to nuclear fission (and has such a high "Z") that it was used to make the radiation case in nuclear weapons where a third "fast-fission" stage was not wanted. Big Ivan, Khrushchev's demonstration of Soviet thermonuclear potency, had a lead radiation case to keep the yield lower than the 100 megatons or so it was theoretically capable of (and the fallout plume less deadly and large) if the radiation case had been made of natural uranium.

There may also be examples of an 'island of stability' among isotopes of elements heavier than plutonium which are related to how the binding energy of a given nucleus relates to its mass in the heavier nuclei and other more esoteric factors such as quantum tunneling. Tentative proofs of this in the superheavy elements beyond the lanthanide/actinide elements (notably, isotopes of Darmstadtium and Seaborgium) have been claimed by US and Russian researchers (who collaborated on such research). loupgarous (talk) 20:22, 2 September 2016 (UTC)

Iron has sometimes been used for radiation shielding as well, though this tends to be for very-high-energy accelerators. There is a trade-off between increasing density (which you see with higher atomic numbers) and the binding energy curve, though, so lead is actually better at shielding normal radioactive materials, and iron only gets used when operating at very high energies when any fission at all is completely unacceptable. Even uranium can be used to shield more radioactive materials! Double sharp (talk) 04:21, 4 September 2016 (UTC)

The more impressive thing about superheavy elements (element 104 onwards) is that they exist at all. If you blindly applied the liquid drop model, you would expect that any nucleus with more than 103 protons would fission before the nucleons could even arrange themselves into nuclear shells. That this doesn't happen shows that shell effects have intervened, so that there is now a "fission" barrier and the nucleus cannot simply roll down the metaphorical hill. When you think about it that way, the added stabilisation comes as just a very nice bonus. The longest-lived superheavy isotopes are expected to be ²⁹¹Cn and ²⁹³Cn, with half-lives of about 1200 years. The problem is making them. If electron capture becomes significant again as a decay mode near the middle of the island, we could reach these isotopes, but detecting them would be a problem when you're sitting around waiting for long-lived single atoms to decay. And even if we figured out how to make macroscopic quantities, 1200 years is still not really acceptable as a half-life for most civilian purposes (the only two radioactive elements that have civilian uses are thorium and uranium with billion-year half-lives, not counting bismuth with its quintillion-year half-life). It is also mighty inconvenient that this happens at copernicium because that element is expected to be a gas at room temperature, as you would expect for eka-mercury. But we will probably be able to think of some way to use it if we can make it in large enough quantities. (Also, I think we've carried out a very successful question hijacking...) Double sharp (talk) 04:31, 4 September 2016 (UTC)

How can dogs sniff packaged drugs?

Do the drugs leak through the plastic? Is it impossible to package drugs without leaving traces everywhere? Or is it simply a case of drug mules poorly executing the whole thing through? Llaanngg (talk) 23:12, 31 August 2016 (UTC)

It's hard to believe but it literally takes just molecules of "stuff" for a dog to be able to sniff it. Mythbusters did a great segment on dogs and tried LOADS of stuff to fool the dogs and they didn't manage to do it, including putting drugs in packages washed with solvents and covered in dirty nappies. In the last segment, one of them got into a proper re-breathing self contained hazmat suit, went through a decontamination shower and had something like 30 minutes to go hide in a forest, the dog still sniffed him out. It's just uncanny how good their sense of smell can be. Vespine (talk) 23:37, 31 August 2016 (UTC)

(ec) Dogs have an AMAZINGLY sensitive nose, capable of detecting trace amounts of compounds that even the best human-made technology cannot replicate. Sadly, Wikipedia's coverage of this is woefully inadequate, per Dog anatomy#Smell. this article covers some of their ability. Dogs can reliably detect odors in the parts per trillion range, which (as noted in that article) is roughly equivalent to being able to taste 1/2 teaspoon of sugar dissolved in an olympic-sized swimming pool. Dogs can smell the trace amounts of body odor you leave behind when you walk through an area. Dogs can even track the direction you have moved by detecting the difference in concentration of body odor left behind as you've moved past an area. The amount of drugs left on the outside of a package, transferred by the hands of the people handling said drugs, is easily detectable to a dog. --Jayron32 23:44, 31 August 2016 (UTC)

It's not obvious, but even things like hazmat suits are not perfectly impermeable. And given how sensitive dogs noses are, as pointed out by Jayron and Vespine, even a wrapping material that is "impermeable" insofar as humans can tell, it may not seem that way to a dog. Someguy1221 (talk) 00:03, 1 September 2016 (UTC)

Maybe the dog just smelled something that didn't belong, that being the hazmat suit. StuRat (talk) 01:20, 1 September 2016 (UTC)

It's been a while, but I think the dog was given a shirt Adam (the guy in the suit) had worn to "sniff out". That doesn't "disprove" the dog didn't just sniff out the hazmat suit, I don't think they had other people in hazmat suits going in different directions, that would have been a better control.. Vespine (talk) 01:31, 1 September 2016 (UTC)

Agreed. StuRat (talk) 03:38, 1 September 2016 (UTC)

I can relate a personal experience about the ability to sense "a few molecules", in this case the sense being burning skin from capsaicin. I cut up a habanero pepper, which is by no means the hottest pepper, being careful not to touch it. However, I then rinsed the knife off with water, then made the mistake of swiping the blade with my right thumb and forefinger, as a finishing touch. Almost immediately I felt burning and realized my mistake. I then washed my hands with soap and water, but that had the effect of spreading the burning to my left hand. Later on, I was being careful not to touch anything with my right hand, figuring it had the most capsaicin on it. However, I scratched my eye with my left hand, and then my eye started to burn. So, if you figure how much the capsaicin must have been diluted at each transfer, it couldn't be many molecules that made it to my eye, yet I sure could feel them. StuRat (talk) 03:38, 1 September 2016 (UTC)

The original case and the case above both have a lot to do with the difference between hydrophobic and hydrophilic. If the substance happens to be hydrophobic, then washing with water doesn't do anything to dilute it really. Soap can be more effective, but it may take quite a bit. And the other thing about hydrophobic substances is that they can move through many plastics as if they weren't even there. To take an arcane example, it is actually practical to label what probe was used on a Northern blot after you have put on the appropriate probe and used a heat sealer to confine it in a plastic bag. You simply take a strongly hydrophobic lab marker and write on it straight through the plastic, and the "ink" goes straight through to the blot; even though the water-based probe solution (more so in former times) was strongly radioactive, no trace of contamination would be detected on the tip of the marker. A simpler example though is if you make the mistake of putting on most types of plastic lab gloves to reach into a small container of xylenes; you may be feeling a (very faint) "high" in seconds, the solvent having soaked straight through gloves and skin alike. The key here is that plastic is just a tough matrix of fibers soaked in plasticizer; it's almost better to think of it as a film of liquid. Creepy aspect of that is that I think stuff like bisphenol A has a much easier time getting into you than you like to think. Anyway, the point here is that the volatile organic compounds dogs learn to recognize will be soaked into the plastic at a concentration at a concentration roughly equal to what they are at the surface of the drugs themselves. An interesting test would be to see whether drugs, placed into a plastic container that is wrapped in hydrophilic material like cotton cloth and placed into a larger container of water, would evade the dogs. But then some would probably wick through the cloth... hmmm... bet some home tinning equipment might do it, if there is no stray plastic lining poking out where the can is sealed... there must be a whole technical database about such things somewhere... Wnt (talk) 11:48, 1 September 2016 (UTC)

Next time you get chilli pepper on your hands or face, remove it with a fatty substance like cream or butter. Water will just make it worse if anything. SpinningSpark 15:19, 1 September 2016 (UTC)

Amount coffees per pound of beans

Espresso#Brewing says 7 g per shot, so that is around 65 cups of coffee per pound of coffee. That doesn't sound right. Am I making a stupid maths error? Anna Frodesiak (talk) 23:55, 31 August 2016 (UTC)

Your maths is good. --Tagishsimon (talk) 23:57, 31 August 2016 (UTC)

How is maths not plural? Sagittarian Milky Way (talk) 00:22, 1 September 2016 (UTC)

In Canada we always said "math". "Maths" is the second least roll-off-the-tongueish word ever right after "wasps". Anna Frodesiak (talk) 00:49, 1 September 2016 (UTC)

Try "lisps". StuRat (talk) 01:17, 1 September 2016 (UTC)

She thrusts her fists/against the posts/and still insists/she sees the ghosts. --Trovatore (talk) 03:09, 1 September 2016 (UTC)

"Crisps"? "Fifths"? "Sixths"? Double sharp (talk) 06:10, 1 September 2016 (UTC)

Squirrels (per Isabella Rossellini) and strengths are by far the hardest American words to say. μηδείς (talk) 21:32, 1 September 2016 (UTC)

SMW: Mathematics is one of your favorite subjects, right? "In English, the noun mathematics takes singular verb forms. It is often shortened to maths or, in English-speaking North America, math.", emphasis mine. This is somewhat an accident of history, based on the Latin, as described in the etymology section of our article. SemanticMantis (talk) 16:22, 2 September 2016 (UTC)

Mathematics isn't plural but who knows what maths is? It sure looks plural.

But it's not so why do they go out of their way to make math sound as plural as possible? Sagittarian Milky Way (talk) 17:50, 2 September 2016 (UTC)

Because it derives from 'Mathematics', not 'Mathematic'. The US version without 's' is very strange and found in almost no other English speaking countries. Akld guy (talk) 04:41, 3 September 2016 (UTC)

There's American English, and there's the rest of English, the "rest" being roughly identifiable with British English. "No other countries" doesn't count; all those countries together add up to about half the native speakers that the US has. --Trovatore (talk) 19:29, 4 September 2016 (UTC)

Isn't the point of abbreviation to avoid effort? (of saying many syllables)? Maths rolls off the tongue like "the sixth sick sheikh's sixth sheep's sick" Sagittarian Milky Way (talk) 19:47, 4 September 2016 (UTC)

Google says 120-140 cups per kilo of coffee. I buy underground coffee by the kilo for a home espresso machine, and while I don't count the number of cups I make from each bag, and i usually drink double shots, that number doesn't surprise me. Vespine (talk) 00:04, 1 September 2016 (UTC)

120-140 cups per kilo?? Astonishing. Is it strong enough? Or as Jasmin said in Bagdad Café, "...that is brown water." Anna Frodesiak (talk) 00:34, 1 September 2016 (UTC)

Well, keep in mind they're very small "cups". It would take quite a few of them to make a cup. --Trovatore (talk) 00:56, 1 September 2016 (UTC)

A "shot" of coffee is an esspresso, MOST people add milk to make a latte or a Cappuccino to make a whole "CUP", depending when and where you are. Vespine (talk) 01:01, 1 September 2016 (UTC)

In Italy, your "shot" is just un caffè (or caffè normale if you want to further specify). Cappuccino is for breakfast; ordering it after noon is a good way to get pegged as a German tourist. Caffellatte is also for breakfast, but at home; you wouldn't normally order it outside. --Trovatore (talk) 01:13, 1 September 2016 (UTC)

Another thing I learned living in Melbourne (the town that invented "deconstructed coffee"), there are fewer more pedant than coffee nerds. Origins aside, you won't find a snobbier coffee culture than Melbourne, and a "latte" or "strong latte" is pretty much the standard way to drink coffee here. I personally drink my coffee long black, but i am not a coffee snob. Vespine (talk) 01:22, 1 September 2016 (UTC)

The first time I ordered coffee in Melbourne I had no idea what the hell was going on -- "long black", "flat white" and so on. I ended up ordering a hot chocolate because I at least knew what I'd be getting. Shock Brigade Harvester Boris (talk) 03:58, 1 September 2016 (UTC)

Strange prices

Coffee beans here in China wholesale at around $5 USD per pound. Single espresso shots here are sold for at least $2.25 USD each. Is this in line with international prices? Anna Frodesiak (talk) 03:34, 1 September 2016 (UTC)

Yes, the markup on coffee at places like Starbucks is truly amazing, and even K-Cups for home use have an incredible mark-up (although the company that makes them, Keurig, did find there is a limit, when they introduced their 2.0 beverage maker, which no longer allowed cheaper third-party cups, and ran into massive customer and retailer rejection). But I suppose the markup isn't much worse than for soft drinks, which can cost $3 in a US restaurant, but only cost maybe a nickel or dime to make. StuRat (talk) 03:47, 1 September 2016 (UTC)

Customer: "I'll have a small coffee with cream."

Cashier yells to barista: "I have a short, full fat, single here !"

Customer: "Hey !"

StuRat (talk) 03:55, 1 September 2016 (UTC)

Not a bad joke. :)

The best coffee joke to date imho was eddie murphy: "I like my coffee like I like my women... Anyone else want a big ass coffee?" Vespine (talk) 04:53, 1 September 2016 (UTC)

I always go with "I like my coffee like I like my women... Frigid and bitter..." --Jayron32 13:19, 1 September 2016 (UTC)

Holy moly. So, that is around $150 into the register for a $5 bag of beans. French fry shops do not sell a $1 potato for $30. Competition makes them sell a $1 potato for $3 or something, right? So, what is it about coffee? Anna Frodesiak (talk) 03:59, 1 September 2016 (UTC)

In the wholesale market, the kg of potatoes also cost just some cents, and they sell a small portion of it for $1.5 or $2. Obviously, you are paying for all the services, space, transport, energy, and so on too. Llaanngg (talk) 04:22, 1 September 2016 (UTC)

I see. So, is there a standard buy for x and sell for y for restaurant food? I've heard that petshops do buy for 1 and sell for 3. What about durables like washing machines? What about other categories of goods? Anna Frodesiak (talk) 05:10, 1 September 2016 (UTC)

Googling for restaurant food markup suggests that an average of 4x (300% markup) as a typical ballpark. DMacks (talk) 05:30, 1 September 2016 (UTC)

Standard brewed U.S. coffee calls for 15 grams of ground beans for an 8 ounce cup. My standard morning mug is neatly twice that size. If I brew at home, which I do most days, the coffee bean cost is not so much, but I am using about four times the seven grams of coffee described above. But when I buy a coffee at Starbuck's, which I do every week or two, I realize that I am buying much more than ground beans and hot water. I am paying for the disposable cup and lid, the wooden stirring stick, the half and half (or other creamers), the regular sugar, the raw sugar, the diet sweetener, the cinnamon, the chocolate, the sleeve so my fingers do not get burned and the carrying case if I order several. Also, I am paying toward the highly visible, high foot traffic commercial lease of the shop, the salaries and fringe benefits of the baristas, the sales tax and all corporate taxes, the gas and electric bill, the liability insurance, the wi-fi costs, the clean restrooms, the free parking spaces, the security guards, the corporate advertising, the stockholder dividends, and the salaries and fringe benefits of all the levels of local, regional and national management plus the enormous wealth of the CEO. It all adds up. Cullen³²⁸ Let's discuss it 05:43, 1 September 2016 (UTC)

That accounts for a lot. Here, things are cheaper, like, workers, rent, cups, etc. The price is same. Anna Frodesiak (talk) 07:04, 1 September 2016 (UTC)

User:Cullen328, you forgot the high pressure coffee machine and its maintenance. And now I am disappointed that my Starbucks doesn't have security guards :-). --Lgriot (talk) 14:14, 1 September 2016 (UTC)

Recent-ish article giving the shop owner's perspective here. TL;DR version: "It’s actually the facilities that cost the money, far more so than the ingredients." Shock Brigade Harvester Boris (talk) 13:27, 1 September 2016 (UTC)

I've often seen things like this [2] which suggest that many retail goods sell for about double the wholesale cost. Expensive durable goods in markets with effective competition and consumer choice, like washing machines, will generally have a smaller markup, e.g. retail for ~1.3 times the wholesale cost [3]. Dragons flight (talk) 09:04, 1 September 2016 (UTC)

A cup of coffee may have a large markup, but it is still only a few dollars of gross profit. Washing machines and other high-value items may have a smaller percentage markup, but the gross profit is much greater than a coffee so fewer need to be sold to cover overheads. SpinningSpark 15:06, 1 September 2016 (UTC)

Note that restaurants have high-markup items, like beverages, anything made from potatoes, and things like the Bloomin' onion (frying also lowers the cost, as it's quick and cheap). They also have low-markup items like most entrees and salads. It's interesting that the unhealthy foods tend to have a higher markup, because the raw ingredients are cheaper. Ideally (for profitability) a location would only sell the high-markup items, but even people used to the unhealthy American diet still complain when they are fed nothing but fries and drinks, with no protein. As for why the markup is less on foods with more expensive ingredients, people are far more willing, and able, to spend $3 for 10 cents worth of ingredients than they are to spend $300 for $10 worth of ingredients. StuRat (talk) 13:44, 1 September 2016 (UTC)

Thank you all for the valuable input. Anna Frodesiak (talk) 07:00, 2 September 2016 (UTC)