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/sci/ - Science & Math


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10221468 No.10221468 [Reply] [Original] [archived.moe]

what evolutionary advantage do the different human phenotypes provide? Why the different skin colors, eyelids, hair, etc?

>> No.10221478

>>10221468
light skin is better for regions with low sunlight exposure (vitamin D), but maladaptive for regions with high sunlight exposure (skin cancer). the pigments of the hair and eyes tend to be correlated with the pigments of the skin, so that just follows from the average sunlight intensity in the regions where those populations are native

>> No.10221489

>>10221478
but why were Native Americans brown in North America?
what about eyes? Even Chinese and Indians have very different eyes and they come from close regions



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10221463 No.10221463 [Reply] [Original] [archived.moe]

It can be anything, from sums to number sequences to images etc..

Here's an easy one :
x + x*(x-1) + x*(x-1)*(x-2) + x*(x-1)*(x-2)*(x-3) ...

Note : Numberphile is banned from this thread



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10221460 No.10221460 [Reply] [Original] [archived.moe]

What is the scientific cause of teenagers going through puberty so early? Is it in the food? Is it in the vaccines?

2 replies omitted. Click Reply to view.
>> No.10221475

yo whos that on the right

>> No.10221476

>>10221475
Danielle Bregoli

>> No.10221482

>>10221476
oh fuck, that's the "cash me ousside" chick rite?

>> No.10221485

>>10221482
Yep.

>> No.10221486

>>10221460
I always feeling wrong about myself for double taking at a girl and then notice the backpack.

What about hormones in chicken, milk, fragrance, etc. lavender has been shown to cause boobs. Stay away from purple shit boys.

Seems the female evolves quickly. You can kinda just see a picture of a chick and guess what decade it was taken. Just like cars.



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10221374 No.10221374 [Reply] [Original] [archived.moe]

>> No.10221381

>>10221374
determinism sucks man, why would you prefer that to the possibility that your future isn’t set in stone since the beginning of the universe?

>> No.10221393
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10221393

>>10221381
What I prefer has nothing to do with the truth.



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10221370 No.10221370 [Reply] [Original] [archived.moe]

Will immortality be possible in our lifetimes?

>> No.10221377

>>10221370
Nope. Delete the thread already.

>> No.10221392

>>10221377
fpbp

>> No.10221418

>>10221370
>Will immortality be possible in our lifetimes?
Yes, but only if you don't die.



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10221366 No.10221366 [Reply] [Original] [archived.moe]

what are the long term implications of micro plastics for life on earth? will life incorporate micro plastic into its systems, or evolve better ways of getting it out of its system?


fish with bones fused with plastic would be pretty cool. what are some interesting ways organisms could incorporate plastic into their bodies?

>> No.10221431
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10221431

Not sure how plastics would be integrated into organisms' lives unless they were used as temporary habitats like a hermit crab would use objects for shells. In evolutionary terms, I don't think integration would happen because plastic decomposes over a few hundred years and adaptations generally arise over millions. Additionally, plastic as a refined material doesn't really make much sense as being integrated into fish bones/organic forms because none are able to synthesize it. Actually, cartilage seems like it's already able to provide the few benefits, like flexibility and compression-resistance, that plastic could in organic forms.
Here's a cool image of Notch signaling for your interest.

>> No.10221441

Oxidizing plastics for energy would be more intriguing, and technically there are some bacteria which can very, very poorly break it down, but I've been thinking about oils lately. Oils and fats have existed for millions of years, easy. Only large animals can deal with them, and in the environment, despite having land life and water life, nothing we've found can quickly process fats and oils, despite them objectively being fantastic energy storage made of common organic components.

>> No.10221471
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10221471

>>10221441

>flying animals with evolved internal jet engines



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10221351 No.10221351 [Reply] [Original] [archived.moe]

How come water at room temperature feels colder than room temperature?

>> No.10221355

>>10221351
Because you're warmer than room temperature and water conducts heat better than air.

>> No.10221368

>>10221355
>>10221355
Sure but how come water that's like 102F feels scorching

>> No.10221375

>>10221355
Also how long would it take for me to sit in room temperature room for me to become room temperature

>> No.10221391

>>10221368
>water that's like 102F feels scorching
Maybe if you're a pussy. But your body can't lose heat to the environment if you're immersed in water warmer than your body. Losing heat to the environment is important for your body to maintain its temperature.

>>10221375
Long enough to be a corpse.



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10221345 No.10221345 [Reply] [Original] [archived.moe]

Am I a genius or a complete retard, I'm betting the latter.

New to circuit design and want to build a robotic hand that uses servos but rotates on a 3V DC motor.

Please help, I've never designed something like this before ... which may be obvious to a pro

12 replies omitted. Click Reply to view.
>> No.10221466

>>10221446
Okay thanks,

>> No.10221469

>>10221465
Yeah 6V power for the pi, I got lazy for 5V and 6V for the servos.

>> No.10221472

>>10221469
"lazy" I mean I know I should lololol

>> No.10221481

>>10221446
Yeah I see what I've done ... ¬¬

>> No.10221490

>>10221469
i don't understand - is that unlabelled pin where the pi's power supply is supposed to go? does it not matter that it's -6 instead of 6?



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10221278 No.10221278 [Reply] [Original] [archived.moe]

i go shopping only rarely (i hate shopping) but i needed new jeans, and to my surprise, probably 95% of mens jeans at stores i went to were something new to me (i heard of them in womens' fashion before but not men's): stretch jeans

so my question is this: is there a scientific reason for why this sort of material is the dominant thing now? what happened to old-fashioned denim? was there some sort of materials-science breakthrough that enabled the stretch material to outperform the 100+ years of denim having the best properties for pants material? or is it some societal thing where now people need stretch more because of, i donno, people's weight fluctuating more lately?

i need some explanation. i would accept that "it's just a fashion trend" but from a fashion point of view, it looks the same basically. so i don't buy that. i have to believe somehow there was a step up in the science underlying stretchy materials that finally filtered through to the market.

7 replies omitted. Click Reply to view.
>> No.10221421

>>10221386
good post. that makes sense. the only thing i’m still not really convinced of is that these materials are cheaper. is it really true that whatever synthetic polymers go into stretchy jeans are now cheaper than old-fashioned cotton? cotton literally “grows on trees” (or bushes? whatever) and i would be surprised if synthetic fibers that mimic it are any cheaper

>> No.10221434

>>10221421
1) It wouldn't have to be cheaper if it improves other qualities of the fabric. It could even be many times more expensive, if the reduction in other material was enough.

2) Spandex can be made from flowing liquid reactants. Plants take time to grow. As for how much cotton is needed, cotton grows in swabs basically. How light is a bag of cotton swabs? How many bushes do you think it would take to make one pair of pants? Plants take time, fertilizer, land, transportation, don't scale very well, etc. A chemical process becomes more efficient an often grows exponentially as we devote more space, besides improvements in process.

If the ingredients that went in spandex were plastic/oil derived, plastics have the advantage that the cost is subsidized by gasoline and plastic usage. Even if it didn't spandex is a polymer and any development in chemicals needed or processing. Cotton has very little usage outside of clothing and medical purposes, and you aren't exactly improving the yield of the cotton plant every year.

>> No.10221454

>>10221434
>plastics have the advantage that the cost is subsidized by gasoline and plastic usage
goddamn, yes, fossil fuels are in everything aren't they. kinda makes me sick to think my new jeans i'm wearing are thanks to evil oil corporations.....

>Even if it didn't spandex is a polymer and any development in chemicals needed or processing.
i feel like you didn't finish this thought -- should it have ended with "...needed or processing would make it cheaper."? i guess that would explain it

i guess your general argument here is that polymers / petroleum-derived materials are so dominant, and come from mines/industrial processes that are lucrative throughout industry, that humble cotton farms are getting out competed thanks to "subsidies" of one form or another plus the continual "progress" in the synthetic chemicals/materials industry. would you say that's a fair characterization of your thoughts?

>> No.10221459

>>10221284
Denim is also harder to machine, it's like heavy upholstery fabric.. These have mass appeal because the fit is always going to be better.

>> No.10221483

>>10221278
but real pants ya slob



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10221252 No.10221252 [DELETED]  [Reply] [Original] [archived.moe]

Your a manager of a store, On a given day 5 separate families spend 22$, 45$, 90$, 26$ and 180$ respectively. Find the number of families in the store originally, if the original average was 62$ and now 65$. Also find the median, mode, range, variance and standard deviation of the five families. Round to the nearest whole. Make a graph



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10221251 No.10221251 [Reply] [Original] [archived.moe]

Is this possible?

I have depression without the sadness/guilt.

8 replies omitted. Click Reply to view.
>> No.10221333

>>10221315
>I'm brown... and live in Scandinavia...
well there's an obvious piece of evidence! how are you supposed to get enough vitamin D when you need much more sunlight exposure than would even be possible during scandinavian winters?
>Regarding supplements, can you compensate their bioavailability by simply taking much larger doses?
no, that really doesn't work. your body simply just craps out absorbing vitamin D from food/drinks after a while; bigger doses don't help, as is evidenced by you being deficient after taking supplements

>I'm sorry for being so ignorant but can I replace the sun by buying a UV light or is that insufficient?
yeah, a UV light, or better yet, a "sunlamp" would be good. but they are much weaker than natural sunlight. i'm sure you can google search about this, i'm sure other brown folk in scandinavia have figured out good ways to get in their (artificial) sunlight quota

>> No.10221338

>>10221282
depression isn’t linked to just one neurological dysfunction, you demonstrate low competence at basic induction and shouldn’t presume you know what you’re talking about with regards to complex mental illnesses where a confluence of many confounding factors and comorbid disorders could be obscuring the actual cause.

>> No.10221360

>>10221333
Thank you, will make sure to go out more and see if I can find a sunlamp!

>>10221338
I'm not sure if you're misinterpreting me or if I'm misinterpreting you but it's pretty clear that most if not all depressive symptoms are caused by an overactive lateral habenula. Why it's overactive is a different, more complex question although we aren't completely ignorant about it.

Are you claiming that the lateral habenula is not single handedly manifesting depressive symptoms? If so do you have any evidence on that or are you talking out of your as?

>> No.10221369

>>10221264
spbp

>> No.10221382

>>10221369
>>10221338
>>10221264

https://www.nature.com/articles/nature25509

Use sci-hub to open it.



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10221195 No.10221195 [Reply] [Original] [archived.moe]

My mom is into science n shit and she would love some cool science related things. If any of you have any cool science things in your room that you enjoy to look at or are just happy about, can you please share them

>> No.10221215

>>10221195
A Newton's Cradle

>> No.10221222

>>10221215
Wow really she doesn't work on the 85th floor of a finance HQ

>> No.10221271

>>10221195
A scale model of the solar system.
A mini Tesla coil.
A trip to a science museum.
All I can think of in short notice gl anon

>> No.10221285

A mini sterling engine like this https://www.amazon.co.uk/Stirling-Engine-Temperature-Motor-Education/dp/B00UUT3KHQ/ref=sr_1_1?ie=UTF8&qid=1545007377&sr=8-1&keywords=sterling+engine

>> No.10221451
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10221451

https://en.m.wikipedia.org/wiki/20Q



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10221155 No.10221155 [Reply] [Original] [archived.moe]

Im legit fucking pissed right now!

How is this not a thing yet? Im talking about an all in 1 nutritional pill which you can just take for the day and youre good, no wasted time cooking or eating.

At the very fucking least can you not create some diet revolving around the consumption of vitamin and mineral pills?? Maybe eat it 3 times a day with a high calorie candy bar or something? Why the fuck has no one looked into this?

>> No.10221158

>>10221155
s o y l e n t

>> No.10221160

>>10221158
fuck outta here

>> No.10221173

>>10221160
It’s exactly what you’re asking for except the pills are included in the powder, I don’t see what your problem is

>> No.10221174

>>10221158
Unironically this. 5 bottles a day is 2000 calories and gives 100% of the nutrition required by the average person. Unfortunately, it just gets boring after a while.

>> No.10221182

Because it's impossible, nutrients occupy space and besides, they are meant to be digested. Even if it was all compressed into a pill the reduced amount of mass ingested would probably cause problems in the digestive system.



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10221133 No.10221133 [Reply] [Original] [archived.moe]

What are the chances of a genius engineering-related discovery in the next 10 years?

3 replies omitted. Click Reply to view.
>> No.10221168

>>10221143
>pnp solution
And straight into the trash it goes

>> No.10221179

>>10221143
Holy shit.

>> No.10221256

>>10221133
What was the last "genius engineering-related discovery" again?

>> No.10221302

>>10221143
Show maths or GTFO

>> No.10221450

>>10221133
Engineers are brainlets.

I'd say 0%.

All autists go for math and physics.



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10221131 No.10221131 [Reply] [Original] [archived.moe]

The only thing I can think of off the top of my head is quantum entanglement or "spooky action at a distance."

6 replies omitted. Click Reply to view.
>> No.10221304

>>10221156
>quantam physics are discrete
Fuck off Bill Nye.

>> No.10221419

I'm suspicious of entanglement as a problem of imagination or axioms. As I've read it, the states immediately after entanglement are related, but that's not surprising. Given a collision which resulted in matter/antimatter, if you found you had a proton, you wouldn't be surprised the opposite particle was an electron.

I have a harder time finding any subsequent interaction exists, which really makes me think it's just a feature of a wave function that it can be "oriented", and a pair (or in fact, any set) of particles has opposite "orientation".

Einstein himself did a founding experiment in Quantum Mechanics which he never accepted: the photovoltaic effect. In continuous physics, electron orbits are ballistic and levels don't exist. In quantum mechanics, properties arise to lock electrons to orbital levels with some quantum noise. When you shine photons on an atom or molecule, only photons which can correspond to the orbital energy +/- noise are absorbable. A photon which is too energy or not energetic enough has near no effect no the atom, whereas classical mechanics says all photons should impart some energy. Photovoltaic effect shows not only are certain photons absorbable, that an electron displaced has a characteristic energy it gains, corresponding to the photon absorbed (which can be directly described an energy exchange in units of electron-volts, or work done by/on moving an electron through one volt of potential). As normal electricity is measured as work done by electrons, electron volts corresponding 1:1 with voltage, so if an electron performs one electron-volt of work, you produced one volt of potential (with the current of one electron).

Photovoltaic is so damn basic, but at the time we just didn't have decent materials, but photonics dominates everything these days. If Einstein lived long enough, he'd be kinda annoyed because he wouldn't be able to explain computers, lasers, LEDs, solar panels, etc.

>> No.10221424

>>10221419
>Given a collision which resulted in matter/antimatter, if you found you had a proton, you wouldn't be surprised the opposite particle was an electron.
>matter/antimatter
>proton
>electron
Uhh....

>> No.10221447

>>10221424
You know what I meant.

>> No.10221484

>>10221419
It's not so easy to explain away entanglement. You use an example like matter/antimatter where (seemingly) there's an obvious choice of the two basis states, the matter state and the antimatter state. For two electrons in a singlet configuration, you have the freedom to perform measurements along two arbitrary axes. It's only if you measure both along the same axis that you reduce to the "obvious" case where they have opposite results.



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10221079 No.10221079 [Reply] [Original] [archived.moe]

2 replies omitted. Click Reply to view.
>> No.10221090

>>10221082
/thread

>> No.10221436

>>10221088
Shhhh...


:-)

>> No.10221449

>>10221082
>>10221088
>>10221436
1 reddit gold has been deposited into your account

>> No.10221467

>>10221449
Rent free, no fee.

>> No.10221477

>>10221079
It's possible but I think its more unlikely than people think, considering how long it took life to get to our level on this planet (billions of years) and how many bullets we had to dodge to get here. Ice ages, impacts, disease, predators, etc.



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10221076 No.10221076 [Reply] [Original] [archived.moe]

Is there a way to create an atomic clock at home for cheap?

>> No.10221099

>>10221076
create an atom at home

>> No.10221196

>>10221076
smoke detectors



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10221068 No.10221068 [Reply] [Original] [archived.moe]

1 replies omitted. Click Reply to view.
>> No.10221096

>>10221068
Presence of OP's mother is correlated with smaller penis length in the given race

>> No.10221108

Testosterone is the primary factor behind penis growth during adolescence iirc.

Asians have exposed themselves to a lot more phytoestrogens than the other races over time.

Africans haven't really had enough wars of the type where all their most violent men get killed. Rather quite the oposite is taking place there. As a result they probably have males with higher testosterone levels.

>> No.10221111

>There is a close correlation between testicle and penis size and promiscuous social strutures in our primate relatives. Gorillas, living in harem social structures, retain a diminuitive penis and testicle size. If you are a male and operate in a promiscuous social structure, producing large quantities of sperm through a delivery system likely to sucessfully distribute those sperm (Margulis & Sagan, 1991), for example in chimpanzees, this gives you a decided advantage over other males. If you are a male living in a heirarchially organized social system, a gorilla harem for example, then copious amount of sperm production or a long penis does not increase your chances of producing progeny. Your ability to prevent other males from sexual contact with females, by force or intimidation, positively influences your chances of reproductive sucess. Human males evidence sexual anatomical characteristics suggestive of a promiscous social structure (Wilson & Daley, 1992). There are exceptions. These are those human males living under highly hierarchial patriarchal monogamous social structures for thousands of years (Miller, 1994).
>Though Darwin hesitated to pursue the implications, human evolution may have unfolded following the dynamic that comes with the benefits of female choice. Trivers (1985) notes that female choice tends to reinforce certain characteristics in the male population. Tanner (1981) applies this principle to human evolution and comes up with a compelling argument that with big headed babies requiring years of care, males disposed to making sure that the children are taken care of would be selected by the females as copulation partners. Human anatomy evidences this suggestion. A large penis and big testicles suggests a non hierarchial promiscous social structure, usually characterized by female sexual selection.

>> No.10221213

is onions consumption associated with small dicks?

>> No.10221337

Black women have thicc thighs and phat asses. it's a lot easier to plow that shit with a big dick.



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10221064 No.10221064 [Reply] [Original] [archived.moe]

I bet that this thought experiment has been made a million times before, because i'm too stupid to have my own ideas, but as i can't find shit on it, here goes:

Imagine this: If there was a computer that could simulate the universe we live in, with which we could see the dawn of the universe, everything that's happened since, and everything that's going to happen. As if reality was a movie, or a book, if you will. My conundrum is: could a computer as such even in theory exist without breaking any fundamental laws of existence? Say if i were to peek an hour into the future with this computer, doesn't that mean i have the power to change it (meaning the computer was wrong from the start)? And if this computer is impossible in theory, does that mean we truly are the masters of our own lives, and not chained to destiny?

>> No.10221083

A computer simulating the universe perfectly would also have to simulate itself perfectly and so on requiring infinite memory

>> No.10221087

>>10221064
Halting problem.

>> No.10221092

There is a name for a computer which, upon gaining access to all available information, can assume all events past and future from a given point in time. However I forget what it is called.

It would however be flawless assuming it had access to all available information. It would have predicted you looking at the future and your likely course of action as a result.

Looking into the future with one of these things would be the kind of experience which would destroy the mind of most people.

>> No.10221094

>>10221087
And as a precursor, Laplace's demon.

>> No.10221095

>>10221092
>There is a name for a computer which, upon gaining access to all available information, can assume all events past and future from a given point in time. However I forget what it is called.

God



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10220997 No.10220997 [Reply] [Original] [archived.moe]

how do i stop feeling like a brainlet for liking chemistry

7 replies omitted. Click Reply to view.
>> No.10221057

>>10221032

This. Also chemistry "feels" wrong. Some of the framework that was built in order to explain certain phenomena falls apart in certain situations, so as a physics fag I'm kind of skeptical of the theory/rules/models all together (one exception to the rule should be enough to throw away the whole rule and replace with something deeper) . I mean why should I bother learning a bunch of quasi-scientific made up rules when some genius is going to unify it in a hundred years.

>> No.10221081

>>10221057
brainlet

>> No.10221085

>>10221057
All science is based on axioms,laws or principles

>> No.10221098

>>10221057
>the physicist's autistic impulse to summarize everything into a tight set of rules from which any scenario can be derived
It's nice, but it fucks you up when you hit a field where it doesn't work, like any field other than physics.

>> No.10221235

>>10221012
I'm a physics major, and I respect chemistry students. A lot. I see it as just a different cup of tea. I'm pretty okay at physics, but not great at chemistry.



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