Wikipedia:Reference desk/Archives/Science/2017 April 4

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April 4

Karate

In karate, approximately how much power does it add to a punch, kick or other striking technique if you do the kiai, vs. if you exhale normally when performing the strike? 2601:646:8E01:7E0B:8C22:6F79:8644:EBB0 (talk) 04:49, 4 April 2017 (UTC)

It depends on the person. Some people strike harder if they mentally get into the whole screaming thing. Some people don't. Bruce Lee made all kinds of silly noises, but did it mostly to keep the opponent confused. Sometimes he would scream when he punched. Sometimes he would scream before he punched. Sometimes he would do his trademark "owwwww" after he punched. Nobody was saying that his punches weren't strong enough. (And before you complain that he did Judo and not Karate, note that he was a Karate instructor.) In my opinion, it is about attitude. If you use it to improve your attitude, you will perform better. 209.149.113.5 (talk) 13:24, 4 April 2017 (UTC)

• In ecky thump, it's essential.

And don't diss ecky thump, unlike Bruce Lee films, it can kill just by being watched. Andy Dingley (talk) 13:34, 4 April 2017 (UTC)

I agree with 209.149.113.5. For many martial artists, this is part of the art, and of sparring "jamming". It can also help for concentration and focus. For instance, one may use a very short and stiff sound while trying to synchronize a body movement with it for speed and power. There are also circumstances where for abdominal protection while striking (a vulnerable moment) it may be useful, and be a side effect more than intentional sounds. Of course, in martial arts culture, the reasons may also extend into metaphysics and mythology, and the anecdotes and teaching vary. Some have compared Dim mak to sneezing. :) —╰]PaleoNeonate█ ⏎ ?ERROR╮ 03:02, 6 April 2017 (UTC)

I forgot to mention it but another aspect is rhythm and motivation, especially in group training (i.e. synchronized kata repetition). —╰]PaleoNeonate█ ⏎ ?ERROR╮ 03:10, 6 April 2017 (UTC)

Well, what I meant to ask if whether it increases the power of an attack by purely physical means (disregarding any psychological effects which may or may not be taking place). 2601:646:8E01:7E0B:F88D:DE34:7772:8E5B (talk) 06:43, 6 April 2017 (UTC)

Muscles of respiration seem relevant - there are abdominal wall muscles that participate in forceful exhalation; our article names rectus abdominus, transverse abdominus, external oblique muscle and internal oblique muscle. These are big broad muscles that seem plausibly usable in martial arts, given that I know zero about martial arts. It seems vaguely sensible to me that if a person had to constrict other muscles to prevent exhalation while constricting these it might take away some trace of oxygen from the ones that mattered for the attack, or if some instinctive fear of over-pressurizing the lungs caused a person to contract the abdominal wall muscles less if there is no exhalation, or ... something. (I know there have been a couple of times with the flu where I coughed so hard I swear I saw a burst of little gas bubbles pass through my retinas ... I'm actually thinking "the bends" but I've never seen anything saying that bubbles in that case are visible) Wnt (talk) 16:16, 6 April 2017 (UTC)

In that respect, you are unlikely to get a well-sourced, empirical answer to your inquiry; there have been passingly few studies on the biomechanics of martial arts in general, and none (to my knowledge) which purport to measure the effect of the kiai on physiological performance or the generated force of a strike. Given the number of conflating factors, such an inquiry would be incredibly difficult to conduct and would require a number of discrete experiments building towards a common understanding, each requiring substantial sample sizes and tight controls. And that's if you kept your main inquiry quite limited in scope; trying to determine how much of the benefit was purely bio-mechanical in a direct fashion and how much an increase in mental focus, which then translates to a bio-mechanical benefit via different mechanisms, would even further difficult--very possibly beyond our capability to determine with current experimental methods, with any degree of certainty.

But, with those empirical caveats made, I can give you some impressionistic insights as someone who has pursued intermittent training in several different forms of martial art/self defense over the years, who also happens to have a good understanding of the physiology involved and a background in mind-body relationships; that is to say, I've had a lot of incidental thoughts over the years about exactly the question you are asking and some related ones about how martial artists focus themselves to achieve some (sometimes quite stupefying) physical feats. To begin with, my impression is that very little of the advantage (whether it is large or small) is likely to be the result of straight-forward biomechanics from the shout. To be certain, you are absolutely correct to postulate that the nature and control of breathing during the execution of a particular maneuver can have substantial effect upon performance, as with any other athletic activity. But note that the shout itself is only incidentally connected with the breathing; the force of exhalation provides part of the volume and auditory quality of the shout, but the sound is also created mostly by the muscles and cavities of the vocal tract. That is to say, it is perfectly possible to achieve the exact same arrangement for the lungs and the rest of the musculature outside the vocal tract, with or without vocalizing a kiai.

So, my impression is that the advantage of the kiai is more likely to result from a more indirect physical benefit (that is, it somehow helps the mind better coordinate its functions for the task of a strike). That said, the actual effect may be quite minimal; that is to say, the notion that it generates more force may be a complete fiction. It certainly wouldn't be too surprising since the usual back-half of that narrative (it helps you generate some sort of qi power that then radiates through your meridians/chakras/spiritual energy pools/whatever) is clearly paranormal nonsense--or, at the least, must be recognized as completely unobserved by science. That said, it is worth noting that most every martial art in the world has incorporated some variant of the kiai. Could it just be that it suits our minds to make an aggressive sound during this motion? Possibly. But I'm not willing to disregard the possibility of an actual impact upon the mind that translates to increased performance. It's certainly within the realm of possibility. On the other hand, as has already been pointed out above, there are other strategic advantages to shouting with a strike that could explain the ubiquitousness of the kiai in martial arts.

I'll finish with some reference to some actual and specific personal experience. I was told by instructors from multiple disciplines that I never quite got the kiai. Perhaps it was a mental thing, a result of skepticism, but I was told I always sounded like I was holding back (I certainly often got the same instruction about my stances, where I was often told that I was holding myself too tense, trying to exert to much control when I needed to be more limber and reliant on muscle memory). But honestly, I always felt like I was screaming my little lungs out to the best of my ability. In any event, I got pretty annoyed with hearing about it time and again, but I never felt comfortable dismissing the purported advantages outright, given the feats of strength I sometimes saw accompany the sound. The most impressive of these came when I was one day allowed to sit in on a demonstration by a number of jujitsu professors (as English-speaking practitioners of certain schools of Jujitsu call their highly ranked, very experienced masters; others use it as a middle-range between regular black-belt instructors and masters). One of the professors was a man of middle-to-late years, just a little short of average height and thin as a rail. To be certain, his slender build looked like it was made from wrapped iron (you know, the Bruce Lee physique), but I was completely unprepared for what he did as he began his kata. In certain forms of jujitsu, they sometimes begin a kata or sparing match with a kind of kiai they call a "spirit shout" and drop to a crouch to pound the ground with both fists. In this case the shout was deafening, but it was the effect of the pounding that left me gobsmacked. This fellow, unimposing in size, shook the 70x70 ft. main room of the dojo like he had dropped a car on top of it. It's a little bit one of those stories where you kind of had to be there to understand just how impressive it was (it sounds underwhelming now that I recount it), but I can tell you that this simple act of pounding the ground was maybe the most impressive display of raw strength I've ever experienced in person--the force it generated in every direction was so strong.

So, that's a little bit more personal perspective and speculation than I generally like to include in my responses here, but hopefully there is enough hard science included to help you get a better understanding to the answer to your question--which is, sad to say, that we have insufficient data to make firm conclusions at this time. And at the very least, you now know that if you are ever going to pick a fight with an old man wearing this belt: [1] ...take a long moment to reconsider! Snow ^{let's rap} 07:25, 7 April 2017 (UTC)

In my case, my karate instructor gave me a rather straightforward explanation -- that when you do the kiai, the abdominal and chest muscles contract simultaneously and add power to the striking technique (which, BTW, is also how he explained the concept of qi in general -- that there's nothing magical or supernatural about it, that it's simply the added power when all of your body's muscles work together). But, if I understood you correctly, then the kiai doesn't add a whole lot of power -- most of it comes from other sources, like hip rotation, whole-body momentum and the like. Thanks! 2601:646:8E01:7E0B:5599:C379:D9A:A1A3 (talk) 11:01, 7 April 2017 (UTC)

Yes, I think you have put it succinctly; the added benefit of synchronicity in the contraction of the chest and abdominal muscles from the kiai is likely to be marginal, compared against the overall leverages of the numerous muscle groups recruited for most strikes. But again, there's the caveat that I don't think there has been much by way of the study of these particular mechanics. And of course, one of the core aspects shared by most martial arts is the striving towards an increasingly ideal execution--so even elements of marginal importance may become the focus of a highly specified approach. Snow ^{let's rap} 11:37, 7 April 2017 (UTC)

Growing plants in a basement

If you had to grow plants in a basement. Could you grow something edible without light, but with proper heat, nutrients and water? Could a potato (or any other root) grow under these conditions until it could nourish a human? --Hofhof (talk) 09:13, 4 April 2017 (UTC)

No, plants absolutely need light for photosynthesis. Plants don't get their energy from their 'food' as animals do, but from light, so without light they simply lack the energy to grow anything. - Lindert (talk) 09:38, 4 April 2017 (UTC)

You can certainly grow mushrooms in your basement. - Nunh-huh 09:40, 4 April 2017 (UTC)

... and they are part of the old Kingdom of Plants (as distinct from animals), but not in the clade Viridiplantae, of course. Dbfirs 10:36, 4 April 2017 (UTC)

Yes, the question was about stuff you can grow to eat, not phylogenetics. Nunh-huh 11:12, 4 April 2017 (UTC)

In that case, maybe some cultures of bacteria might be more successful, but the question said "plants" and Lindert was obviously thinking of Viridiplantae, so I was just clarifying. Dbfirs 17:14, 4 April 2017 (UTC)

I don't think it's as obvious as you seem to think. Just clarifying. - Nunh-huh 23:35, 4 April 2017 (UTC)

Could you grow bean sprouts? — Preceding unsigned comment added by Hofhof (talk • contribs) 09:42, 4 April 2017 (UTC)

Absolutely. But you'd get more calories if you just ate the beans instead. --Trovatore (talk) 10:06, 4 April 2017 (UTC)

Interesting. Bean_sprout#Cultivation says not. 196.213.35.146 (talk) 10:08, 4 April 2017 (UTC)

Does it? I don't see that there. --Trovatore (talk) 10:16, 4 April 2017 (UTC)

"The main principles are: selecting good seed (new and uniform), ensuring that light reaches the seeds..." 196.213.35.146 (talk) 10:19, 4 April 2017 (UTC)

That says that's the recommended way. It doesn't say you can't grow them without light. --Trovatore (talk) 10:21, 4 April 2017 (UTC)

Sure. But in a warm, moist and dark environment you will probably end up cultivating mold/fungus on the said beans. 196.213.35.146 (talk) 10:28, 4 April 2017 (UTC)

Hofhof asked, can you grow bean sprouts? The answer is, yes, you can grow bean sprouts. --Trovatore (talk) 10:29, 4 April 2017 (UTC)

(ec) The first few days the plant doesn't need light, because this naturally happens underground. The plant uses the energy reserves in the bean until the leaves get enough sunlight to take over. - Lindert (talk) 10:18, 4 April 2017 (UTC)

• Depending on your definition of plant, it may or may not include organisms that do not use photosynthesis, such as fungi (mushrooms). This being said, green plants "breathe" like animals do (they do not die at night), so it is not outright implausible that they could survive without light (even if that is clearly not in optimal growth conditions). Tigraan^{Click here to contact me} 10:50, 4 April 2017 (UTC)

The problem is "grow". Energy must come from somewhere if the plant is to grow significantly. This energy could be from a seed or a tuber or corm or rhizome, but, to thrive and grow normally, green plants need to photosynthesise to obtain energy. Dbfirs 11:05, 4 April 2017 (UTC)

Reiterating what Dbfirs said. One can grow rhubarb, dandelion [2] and a lot of other plants in a dark, light free, warm basement but it needs a health root stock to start with. Rhubarb Triangle states that at the end of the growing season the exhausted root stock is used for compost. The next crop needs to spend three years in the open fields first - to built up that reserve and same with dandelion etc. --Aspro (talk) 12:03, 4 April 2017 (UTC)

I can't find a reference to him now but an English lord a couple of centuries ago built some buildings in which he hoped to grow vegetables - but he didn't put in any windows! Of course it wasn't a success. Even the Romans knew one had to expose plants to the sun to grow. Dmcq (talk) 14:06, 4 April 2017 (UTC)

@Hofhof:, the above answers seem to be considering growth conditions with literally no light. Which rules out almost everything save fungi. However, most basements I've been in have some poor light (e.g. a few high windows) or can be fitted with artificial light. Given weak light or artificial light, you have many more options for plants, though many traditional crops will still perform poorly without direct sunlight. Are you also interested in those low light scenarios? Dragons flight (talk) 14:09, 4 April 2017 (UTC)

• I was asking with literally no light, but I had in mind that it might exist a plant (or similar) able to use heat as energy, that is, some sort of edible autotroph capable of chemosynthesis. Hofhof (talk) 12:50, 5 April 2017 (UTC)

If you are using lights can I suggest you used LED light? Especially ones with a lot of blue in them. Give the plants the light they can use rather than just generating heat. Dmcq (talk) 15:48, 4 April 2017 (UTC)

@Andy Dingley: That is the kind of statement that screams . None thinks you made it up and surely you remember having read it somewhere, but if I had a dollar for every time I was damn sure source X said Y when actually it did not, I would be rich. Tigraan^{Click here to contact me} 16:20, 4 April 2017 (UTC)

You want a citation for Ecky-Thump?!!! Well here is one: [3]. P.S. You may be wise to not to view the episode yourself unless you have a doctor present to provide resuscitation... Mind you, it did cure me of asthma.--Aspro (talk) 17:41, 4 April 2017 (UTC)

I'm not sure what you're doubting, but you can read all about it on the world's greatest encyclopedia. Grow_light#LEDs_(Light_Emitting_Diodes)

ApLundell (talk) 17:22, 4 April 2017 (UTC)

ApLundell just beat me to this but that article does in fact indicate that both red and blue are needed and a bit of green can also help. From looking at the web it seems cannabis growers are big users of this technology. :) Dmcq (talk) 17:28, 4 April 2017 (UTC)

Absorbance spectra of chlorophyll a (blue) and chlorophyll b (red).

The basic concept is easy to understand. Green plants are green because they reflect green wavelengths and absorb red and blue wavelengths. Only the absorbed light is used by the plant, so why waste energy on light that will not be used? Note that other Photosynthetic pigments exist, that different species of plants do better with different mixes of colors, and that even with a single species, the best color mix for for leaf growth may not be the best for encouraging flowering. Here is a technical paper on the subject:[4] (Full disclosure: I am an electronics engineer and I designed one of the more popular LED grow lights currently on the market) --Guy Macon (talk) 09:57, 5 April 2017 (UTC)

What was the nature of the LED elements in your design? It's interesting to note there has been a recent shift towards COB (chip on board) LEDs which have a much wider spectral distribution as compared to early LED grow lights which tended to be mixes of red and blue elements. 204.28.125.102 (talk) 22:50, 5 April 2017 (UTC)

I can't say too much without revealing trade secrets, but I can say that Cree is the place to start and that no array of wide spectrum LEDs will outperform an array with a mix of red, blue, and a small amount of white optimized for the particular plant you are trying to grow. See http://www.cree.com/led-components/media/documents/CreeXLampHorticultureFeatureSheet.pdf and http://www.ledsmagazine.com/articles/print/volume-13/issue-7/features/horticulture/science-advances-in-matching-led-lighting-to-horticultural-needs.html Also, when you think about the most successful LED system I designed, think "something you eat" as opposed to "something you smoke". I have worked on those other kinds as well, but that market isn't really looking for a system that will minimize costs and maximize yield over a ten-year period, which is what I was shooting for. --Guy Macon (talk) 20:17, 8 April 2017 (UTC)

Cultivated plant from Hunan, China

• 

How is this plant called?--MedioWikiInit (talk) 14:08, 4 April 2017 (UTC)

Lotus? Although that's a wild guess. Andy Dingley (talk) 14:33, 4 April 2017 (UTC)

This is just a wild guess from looking at its morphology but it looks a dead ringer for something like Nelumbo nucifera.--Aspro (talk) 14:38, 4 April 2017 (UTC)

The description of the picture on Wiki Commons is "Xiangtan County lotus seed (Taobao search shop; Zhen Xiang Xiang)" (Google auto translation) Rojomoke (talk) 14:41, 4 April 2017 (UTC)

So the Wikimedia Commons description for this image, perhaps needs to be improved with an addition of an English description saying that they are locusts Agrharr... Am about to take de hameir to my spell-chequer.--Aspro (talk) 15:03, 4 April 2017 (UTC)