Wikipedia:Reference desk/Archives/Science/2016 March 6

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March 6

white substance in the kidney in picture on wikipedia

what is the name of the white matter inside the kidney which is found in the article (kidney) on Wikipedia (here). There is no information about it there. There is an image which describes the parts of the kidney and I can not see it there. 93.126.95.68 (talk) 01:12, 6 March 2016 (UTC)

Do you mean the pic of the pig's kidney, here: Kidney#In_other_animals ? StuRat (talk) 01:25, 6 March 2016 (UTC)

Yes. 93.126.95.68 (talk) 02:24, 6 March 2016 (UTC)

In the image you and StuRat link the white material is the ureter. The tube of the ureter fans out inside the body of the kidney to collect the urine produced by the nephrons, this is clearly seen in the diagram of the kidney in the same article. Richard Avery (talk)

Renal pelvis. --TammyMoet (talk) 09:16, 6 March 2016 (UTC)

I think in general the kidney starts off with a rich blood supply to be filtered at the outside, and gets lighter as you go further in to tissue that is more structural, with little functional demand for blood flow and more extracellular matrix. So the renal pyramid, for example, is redder at the base, whiter at the tip, as it gets more and more large tubules packed together, with a loose interstitial material. But I think the white shade you're looking for begins at the minor renal calyx and continues on from there. There is also renal sinus space. In these regions fat makes up a portion of the tissue - you can see at [1] how white a region with fat can be. I think the urothelium is not really that dark either. Fat and collagen (to form tough ducts) are both just accumulations of stored material, essentially, with relatively low metabolic needs. Wnt (talk) 18:24, 6 March 2016 (UTC)

Questions instead of hypotheses

Can an experiment be carried out in the same way that Mythbusters do it: by asking a question and then performing the experiment? Since middle school I've had to come up with hypotheses for lab assignments that tasked me with finding what happens for various things. Strikes me as superfluous. — Melab±1 ☎ 02:45, 6 March 2016 (UTC)

They're trying to teach you how to think like a scientist. ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:55, 6 March 2016 (UTC)

Mythbusters does seem rather unscientific. One error they make repeatedly is assuming that since they can't do X, then it isn't possible, without considering that they might not have had the right set up. StuRat (talk) 03:08, 6 March 2016 (UTC)

Yes you could, but usually experiments are made to check a theory, rather than the "what happens if I electrolyse water and then spark the resulting gas" type experiment. Quick answer in that case involves a cross parent. Greglocock (talk) 03:33, 6 March 2016 (UTC)

On the other hand, most of the work on catalysts has been by massive numbers of experiments as the theories about how catalysts work were sketchy at best. Pharma work has also been heavily dependent on massive numbers of experiments. In short - this is a very complex question. Collect (talk) 03:45, 6 March 2016 (UTC)

It's pretty easy to extend "asking a question" to "forming a hypothesis"...just try predict the outcome of the experiment before you do it based on some kind of pre-known set of facts and rational thought process. For Greglocock's example, one could say "I heard that the formula for water is H2O, so I think that electrolysis will give me hydrogen and oxygen gases...if so, they'll burn when I spark them". If they don't, I'm probably making some other gas instead. For Collect's example, one doesn't need to know how something works to perform experiments that probe the the cases where it works. "This catalyst works on compound X, and compound Y is similar to X, so I think it will work on Y also." If it doesn't work, there's something about Y as compared to X that prevents the catalyst from working. Both cases one has a basis for thinking something will work a certain way rather than going in blindly. And if it doesn't, one learns something about one's underlying assumptions and an obvious route of what to study next to figure out more ("future work", in the scientific-method parlance). DMacks (talk) 04:09, 6 March 2016 (UTC)

But that seems unnecessary. On one episode they had to determine if a plow could slice a car in half. If that was one of my labs, I'd be asked to form a hypothesis as to what would happen when the plow slams into the car. While that may be interesting, it contributes nothing to the conclusion aside from making it more awkward to write. — Melab±1 ☎ 21:25, 9 March 2016 (UTC)

• Any question can be framed as an hypothesis, and vice versa. The way you frame it is irrelevant, the way you investigate it isn't. Although Mythbusters are far from thorough most of the time, they're at least teaching people to question and think. Never a bad thing. Fgf10 (talk) 10:20, 6 March 2016 (UTC)

Not every question can be transformed into a scientific hypothesis. The latter has to be falsifiable. Something has to happen to be able to settle it. That's why questions about God's existence is not a hypothesis. Scicurious (talk) 18:15, 6 March 2016 (UTC)

True to some extend, although I would say that "Does God exist?" is essentially equally nonsensical as "I hypothesise that God exists". My statement assumed falsifiable questions/statements, as we are on the Science Ref Desk. Fgf10 (talk) 08:07, 7 March 2016 (UTC)

It's not inherently nonsensical, it's merely incomplete: The hypothesis does not define "God". So there's nowhere to go with it. ←Baseball Bugs ^{What's up, Doc?} carrots→ 09:09, 7 March 2016 (UTC)

Well...the deeper problem is that there is a claim that God is "omnipotent" and "omniscient" - and any being or entity for which those claims are made is immunized against the scientific method. If (hypothetically) there were some experiment I could perform to prove the existence of God - then he can just use his omniscience to know that I'm going to do it - and his omnipotence to change the result from "true" to "false"...presumably to "test my faith" or some such excuse. So even if I were to be able to do such an experiment, a "false" result wouldn't convince any religious OR scientific people because of the "omniscient"/"omnipotent"/"wishes-to-test-our-faith" triangle. That makes the "god-hypothesis" unfalsifiable. Religious people then take this as some kind of proof that they're right - when in fact, there are any number of equally unfalsifiable hypotheses (such as that we should believe in Odin and Valhalla and die as bloodthirsty killers in order to get into an afterlife full of quaffing and orgying). So, here is a tip for anyone who wants to make something that people will believe in and which science will be unable to disprove: Make it unfalsifiable - use infinities in your argument. So the only part of the description of "God" that matters is "omnipotent" and "omniscient". Take away those, and we might stand a chance of proving/disproving this hypothetical being's existence. SteveBaker (talk) 16:27, 8 March 2016 (UTC)

The difference is rooted in the philosophy of science. The classical positivist science approach poses falsifiable hypotheses about the relationship between two or more variables that can be tested. The falsifibility, statement of relationship, presence of variables, and testability are all key. Not all questions have those elements. But more importantly is that science never finds answers to questions. It simply fails to find evidence disproving the hypothesis. In other words we find enough evidence to reject the null hypothesis (the version of the hypothesis which claims no relationship between the variables). Fail to find evidence disproving it enough times and we start to assume it is likely a correct statement. But we can never be sure. It is possible we just keep having fluke experiments over and over (see quantum suicide). EvergreenFir (talk) Please {{re}} 18:45, 6 March 2016 (UTC)

This is all good and correct, but I'll add that WP:OR any practicing scientist will tell OP that what we teach about scientific method can be very different from how we practice scientific method, especially in interdisciplinary sciences. For example, hypotheses are often crafted ex post facto for purposes of writing a clean manuscript, and publication bias skews our available evidence of negative results. 14:24, 7 March 2016 (UTC)

Very true. I think everyone admits to at least tweaking the "front end" of a paper to better match (or perhaps to better facilitate discussion in) the "back end". Some do go quite a bit further though. EvergreenFir (talk) Please {{re}} 06:10, 9 March 2016 (UTC)

• A hypothesis is equivalent to a yes/no question. Questions that are open ended, or allow for a range of answers, are not equivalent to hypotheses. Looie496 (talk) 15:53, 7 March 2016 (UTC)

Having a specific hypothesis rather than just a question is very useful: it helps you to focus not just on what you want to know, but on how to construct the experiment such that you actually learn something from it. Asking a question and doing an experiment to look for "an answer" can mislead you, because there may be multiple reasons why the experiment comes out the way it does, and you may not have thought of all of them. Forming a hypothesis and trying to disprove it encourages you to think through the problem in a way that leads to a well-designed experiment.--Srleffler (talk) 03:33, 8 March 2016 (UTC)

Some people (notably Albert Einstein) argue that because we cannot measure both the position and the velocity of a particle quantum theory is incomplete. In the case of God, we have a complete theory, as expounded by Jesus Christ. All it takes for enlightenment is to read the Bible. 94.192.182.71 (talk) 13:06, 8 March 2016 (UTC)

This is something often said by people who have never opened the Bible at page 1 and read it through to the last page. I've actually done that - it's an utter mess of confusing, contradictory - frequently horrifying and quite disconnected stories. Far from being enlightened - it convinced me that atheism is the only reasonable response! So no, you're wrong. If you truly believe what you say, then stop cherry-picking the 'good bits' that your local priest tells you to read - and start at page 1 and read through to the end. Trust me, you'll learn something - and it won't be "Jesus tells you all about God"!

You don't have a complete theory of God - you can't answer basic questions like "How was God created?" or "Why does God make diseases that kill innocent little babies?" or "Can God make a rock so heavy that he can't lift it?" or "Why the heck does he insist on not providing concrete evidence of his existence?" or "Why did he confuse everyone by burying all of those fake dinosaur bones?". You can't tell me why your 'theory' of God is the correct one when the other few hundred religions or the world insist that theirs is the correct one. There are a million simple questions that your "theory" can't answer. Can you tell me why the nerve that controls one side of your larynx goes all the way down your neck into your chest cavity, wraps around an artery, then comes all the way back up your neck again - while the one on the other side goes directly to the brain by the straightest route? I can...using the science of evolution. In the end, religions answer these questions with pathetic answers like "God wants it like that" or "It's to test our faith" or "God works in mysterious ways". All kinds of really transparent bullshit. Copouts. In science, there are no copouts. If there is something we don't understand, we come right out and say it. "We don't understand dark energy" or "String theory looks good - but we can't prove it". Nothing gets pushed under the rug. We work tirelessly to try to provide answers where we don't have them. (Religions work hard to bury things that aren't explained). On the other hand, when we DO know something (like why that larynx nerve goes that crazy route), we don't only explain it - we provide explanations for the explanations - all the way back to actual experiments that you can (in principle) do for yourself to convince yourself of those things. SteveBaker (talk) 16:15, 8 March 2016 (UTC)

One of these days we ought to just get a room already and have the great religion debate to end all religion debates. But there are different formulations of religion, not all of which assign divine truth to every last syllable in the Old Testament, for example; while you perhaps rightly oppose a certain conventional form of religion you certainly can't dispute other versions so easily. In general, the "cop-out" of religion should be balanced by the cop-out of science, which is to say, a complete unwillingness to go beyond what the data can tell us - including whether there are billions of copies of us being made every nanosecond, for example, which is just an "interpretation" of the math and unworthy of speculation. Religion goes in and thinks, or should think, about all the matters outside this one lonely universe we can study - including the provenance of that universe. I could give responses for some of the old questions you cite (whether they're true or not is another question....) Wnt (talk) 23:31, 8 March 2016 (UTC)

I think the OP is partly right. I have had the scientific method preached at me, but I haven't seen clear proof that any particular formulation is "genuinely right", and in fact, I see various formulations that don't agree. I think the idea that there was a huge jump between "dark ages" and "age of reason" is exaggerated. Yes, there are specific tricks that improve scientific method, like blind trials and double-blind trials and statistical significance calculations (though the commonly used 5% threshold there is more ad hoc magic, and the source of endless ponderous philosophizing lately as people realize that publishing 5% of all the random things people choose to look at in studies is a lot). But "why don't we try it and see what happens" is a fair approach in science - it played a huge role in early chemistry, for example.

That said, having a hypothesis is an elegant thing that can pay off, and counts as one of the useful tricks. The notion is that experiments take some kind of planning. I mean, you can put a cockroach shell between a pair of diamond anvils and see what happens, sure, but ... see what what happens? I mean, are you going to be looking at it through a microscope? Then you're hypothesizing that its appearance in visual light will change. Why? What chemicals are going to change form to make that happen? Are you going to pick it out afterward and run chemical tests? Then you're hypothesizing some kind of reaction that occurs only under high pressure. Why? Are you measuring the charge between two points? Why, you think it's piezoelectric? Etcetera. Note that this kind of "hypothesizing" is often less a question of what you think ought to happen than what you think is easiest to look at. A lot of genetics experiments are like this - people look for changes in mRNA level because it's easier to do than, say, looking at what happens to the chromatin on the DNA. Doesn't matter that the effect on the chromatin is more directly and logically expected from many treatments - your "hypothesis" is formed by convenience, not prediction. Wnt (talk) 23:21, 8 March 2016 (UTC)

File:WH3.JPG

Another question about the identity of a location: Does someone know what this file is a skyline of? Jo-Jo Eumerus (talk, contributions) 11:28, 6 March 2016 (UTC)

Given the title, and looking at the original uploader's short list of contributions, it's a good bet that it's Winter Haven, Florida. ←Baseball Bugs ^{What's up, Doc?} carrots→ 12:00, 6 March 2016 (UTC)

Yes. Compare with this. ←Baseball Bugs ^{What's up, Doc?} carrots→ 12:04, 6 March 2016 (UTC)

Thanks, moved it to a better name (after first moving it to Winter by mistake...) Jo-Jo Eumerus (talk, contributions) 19:43, 6 March 2016 (UTC)

Winter Haven is correct. Anything that has "Witner" is a typo. --Amble (talk) 18:11, 7 March 2016 (UTC)

Ha, that explains why I couldn't find it in the search box - I insisted on spelling it correctly. It's File:Skyline of Witner Haven, FL.JPG. Presumably there's a way to get that error fixed? (It's only been wrong since 2010.) ←Baseball Bugs ^{What's up, Doc?} carrots→ 20:51, 7 March 2016 (UTC)

I have added a rename request template to both images. --Amble (talk) 21:53, 7 March 2016 (UTC)

Thanks to Widr for performing the moves. --Amble (talk) 16:40, 8 March 2016 (UTC)

• What happens when you click on the section title? My result is weird. —Tamfang (talk) 02:19, 8 March 2016 (UTC)

That confused me too at first. It's because the Winter Haven images were uploaded directly to English Wikipedia. One of those was named WH3.JPG. But since that file has been renamed, there is no longer a WH3.JPG on English Wikipedia, but there does happen to be an unrelated file with the same name on Wikimedia commons. So now when you click on the link, you get that one instead. --Amble (talk) 06:22, 8 March 2016 (UTC)

Skin cancer from smoking

This 1956 article raised the issue of smoking causing lung cancer. One of the author's lesser topics regarded tar and condensed smoke causing skin cancer when they were, essentially, "painted" on the skin of various other mammals. Today, nobody seriously disputes the idea that smoking raises the risk of lung cancer, and secondhand smoke is sometimes an issue, but we virtually never hear about secondhand smoke causing skin cancer. Has such an idea been disproven, or is it merely minor enough that it just doesn't get much attention? Nyttend (talk) 17:29, 6 March 2016 (UTC)

I had never heard that before, so I googled "cigarettes and skin cancer". A number of items came up, including this from 2012, which says smoking significantly increases the risk of skin cancer. ←Baseball Bugs ^{What's up, Doc?} carrots→ 17:51, 6 March 2016 (UTC)

There are several unrelated cancers that are called "skin cancer". So, the answer to this question depends on exactly what cancer you mean. Ruslik_Zero 19:48, 6 March 2016 (UTC)

I'm actually interested in a slightly different thing: the effects of smoke (not smoking) on the skin. In the experiment addressed in the article, cigarette tar and "condensed" smoke were pasted onto mice; three-fifths developed papillomae, and almost half developed what the article calls "true cancer". Obviously, tobacco smoke is the only cigarette byproduct regularly in contact with the human skin, and I suppose secondhand smoke would be the best mechanism for testing this issue; the article Bugs found says that smoking weakens the immune system, so that's another variable you'd have to consider when studying the effects of cigarette byproducts on the skin of smokers, but not for nonsmokers. Nyttend (talk) 20:19, 6 March 2016 (UTC)

I don't think it was ever suggested that cigarette smoke would cause skin cancer. It would appear from the article that painting the tar on the skin was just to see what effect it would have on living cells in high concentrations. As it says, inhalation experiments weren't producing lung cancer in animals so the next step would be to see what effect higher concentrations had. They couldn't get the rodents to inhale the tar so it was easier to paint it onto the skin. it's the same principle as when they test something like artificial sweeteners by giving them to rats in concentrations that are higher then anyone could achieve by ingesting them in food and drink. Hopefully any problems will show up much quicker that way. Richerman (talk) 22:24, 6 March 2016 (UTC)

I think it falls under the "minor" category. Public health messaging probably doesn't focus on it because by far the leading cause of skin cancer is UV exposure. So for reducing skin cancer, it's much more important to promote limiting sunlight exposure and use of sunscreen. As for messaging about secondhand smoke, its effects on the respiratory system are more well-studied, so it's just easier to cite that. --71.119.131.184 (talk) 22:29, 6 March 2016 (UTC)

Maybe we need to convince everyone to smoke so much that the smoke clouds block the sunlight. :-) StuRat (talk) 14:48, 7 March 2016 (UTC)

Need to drill inverted cone into top of LED

I have an LED lighting project where I need low power RGB LEDs to provide as much light to the side as possible. I'm unable to find any lower power LEDs with an [inverted cone lens] so I'm going to try drilling/cutting an inverted cone shape into the plastic of regular RGB LEDs with my small rotary tool. Is this idea clearly flawed? --92.6.114.99 (talk) 21:38, 6 March 2016 (UTC)

Not at all! Using a small lathe might be an idea. Use a file (tool) before. Mayme a treatmend with sand by abrasive blasting or a P80 / P100 Sandpaper might fulfill Your need. --Hans Haase (有问题吗) 22:15, 6 March 2016 (UTC)

If You want to restore a clear surface, You need to use a P2000 or higher fine sandpaper, used to prepare car paint coating, used with water as a release agent tu use the paper for more applications and better results. Using the lathe, mount the drill fixed and rotate the LED. Using a sharp drill will crash the LED and other platic. See how to prepare a drill for metal and how to apply it on plastic. --Hans Haase (有问题吗) 23:39, 6 March 2016 (UTC)

Actually, coating with metallic paint or tinfoil to reflect the light will work better.--TMCk (talk) 23:45, 6 March 2016 (UTC)

I'm wondering if a curved mirror behind the LEDs might be a better option, to redirect light headed in the wrong direction to the direction you have in mind. This is how LED flashlights tend to work, so you might use parts from those. Can you describe your application ? Specifically, how closely are the LEDs to be packed ? StuRat (talk) 14:41, 7 March 2016 (UTC)

I don't think your read the question closely enough! The OP wants MORE light at the sides - which is the entire point of inverted-cone lenses that reflect the light that would normally exit from the center of the lens to shine out at the sides. A convex mirror positioned in front of the LED might work - but it's a pain to manage physically. Drilling a conical hole in the front of the LED is by far the best solution - but you need the right kind of drill bit, some means for holding the LED in place, and a reasonably accurate control of the depth of the hole. The sides of the hole need to be fairly smooth, so a higher RPM drill might be preferable. SteveBaker (talk) 20:25, 7 March 2016 (UTC)

Where I said to put the mirror "behind" the LED, read that as "in the location where you don't want the light to go". So, if the goal is to have a single LED spread light to the sides instead of straight forward, then the mirror should be in front of the LED. The cone shape sounds good, except for the noted problems below. The use of the word "lens" instead of "mirror" for something that reflects rather than refracts light just didn't seem right to me. StuRat (talk) 05:14, 9 March 2016 (UTC)

I see a potential problem which may explain why nobody makes RGB inverted cone (also known as concave cylindrical) LEDs. If you look at http://www.quickar.com/wic6.jpg (from the http://www.moreleds.com/whiteinverted.htm webpage) you will see the banding that is typical of inverted cone LEDs. and RGB LED has the three dies next to each other, so each color will have the bands shifted. This will cause a rainbow effect instead of the desired even color mixing.

Have you considered making a small cover out of white translucent plastic? --Guy Macon (talk) 09:20, 8 March 2016 (UTC)

Here is somebody selling them on the Italian ebay: [2] perhaps you can figure out where they are sourcing them? Also, note the color problems I mentioned above. --Guy Macon (talk) 09:37, 8 March 2016 (UTC)

The avail sample might be a question of the price. The need to modify the LED is in changing its light emitting characteristics. Such LEDs usually were designed as a spotlight, emitting most of the light in an angle of 10 to 30 gedrees. Philips came up with such inverted but diffuse cones, to giving the LED a 360 light emitting characteristic. Another idea depending on the applications mght be to look for socalled "filament LEDs". --Hans Haase (有问题吗) 14:49, 8 March 2016 (UTC)

I suppose I should ask the obvious question: "Have you considered using multiple LEDs, pointing to the side, to get the desired effect ?". Considering the low cost of LEDs, this seems feasible, to me. StuRat (talk) 05:19, 9 March 2016 (UTC)