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#4289 - dudeheit
Reply 0
(03/11/2015) [-]
Can anyone help a poor biologist who struggles with biophysics because he doesn't know shit about physic in generel?
I try to translate the task as best as I can, I'm no native english-speaker.
So a fish has an average heat quantity of 2500 J which he releases per hour at the surrounding water which has a temperature of 10°C. At which rate does the entropy change over the course ov 4 hours? The answer is -35,3 J K^-1 but I have absolutly no clue how to calculate that shit ...
Thanks to everyone in advance
#4304 to #4289 - theuntakenusername
Reply +1
(03/13/2015) [-]
Hi! I have some eperience with thermodynamics and you need the following formula:

S=dQ/T

Where S is entropy, T is temperature of the surroundings(10 C but you fill it in as 283 K) and dQ is the heat exchange. This heat exchange you fill in as 2500 J/hour * 4 hours = 10000 J.

So then 10000 J/283 K gives your answer. By the way, google is your friend in most of these cases
#4307 to #4304 - dudeheit
Reply 0
(03/14/2015) [-]
Aw you are quite the man, thanks!
I did found that formula in my script and the internet but I couldn't figure out how I should put in the time, but as i look at it now, the "d" from "dQ" means over time or something like this, doesn't it?
Still If i divide 10000J / 283 K it equals +35 J / K and not - 35 J /K ?
#4308 to #4307 - theuntakenusername
Reply +1
(03/14/2015) [-]
Sorry, I forgot to explain the minus, and it all depends for which system you have to calculate the entropy entropy . For the fish, its entropy will decrease because it releases energy, so a negative change. The surroundings will have an entropy change that is exactly the opposite.

So the final formula(when filled in) should be:

Sfish = -10000J / 283K = -35.3 J/K
#4309 to #4308 - dudeheit
Reply 0
(03/14/2015) [-]
Damn thats total logical.Again thank you for your kind explanation!
#4287 - Izen
Reply 0
(03/11/2015) [-]
So I'm writing a story and need some help,
What do y'all think aliens look like?
#4302 to #4287 - nimba
Reply 0
(03/12/2015) [-]
like bacteria
#4277 - xgreenmaidenx
Reply +1
(03/09/2015) [-]
What's the science behind homosexuality? How to you "turn" gay in the first place? Is it genetics, what is it?
I need to know for school, but Google and YouTube isn't helping. All I get is religious people trying to debunk everything scientists say about it.
And if you know any good websites I can read about it, then it would be extra helpful.
Thank you in before hand.
#4300 to #4277 - kanadetenshi
Reply 0
(03/12/2015) [-]
Look up some of the research done by Dick Swaab, probably one of the better studies done on it.
#4343 to #4300 - cognosceteipsum
Reply +1
(03/18/2015) [-]
Heh. Dick.
#4298 to #4277 - phtholognyrrh
Reply +2
(03/12/2015) [-]
it isnt a choice. beyond that there is too much "science" for both sides of the argument. it would seem that animals have a sexual orientation spectrum, where they exhibit more or less hetero or homo sex behaviors. in humans, however, social taboos make identification and research difficult.
#4280 to #4277 - schnizel
Reply 0
(03/10/2015) [-]
#4291 to #4280 - nimba
Reply 0
(03/11/2015) [-]
lol
#4292 to #4291 - schnizel
Reply 0
(03/11/2015) [-]
Why are you laughing out loud?
#4293 to #4292 - nimba
Reply 0
(03/11/2015) [-]
because of the joke thay guy made
#4294 to #4293 - schnizel
Reply 0
(03/11/2015) [-]
No, gays are completely normal people.
#4283 to #4280 - xgreenmaidenx
Reply +1
(03/10/2015) [-]
I appreciate the contribution, but that's just a hypothesis made by some random dude on the Internet.
#4284 to #4283 - schnizel
Reply 0
(03/10/2015) [-]
But what is going to stop me beating up fags?
#4285 to #4284 - xgreenmaidenx
Reply +1
(03/10/2015) [-]
The police.
#4286 to #4285 - schnizel
Reply 0
(03/10/2015) [-]
Darn it.
#4279 to #4277 - skoldpaddacommala
Reply +2
(03/10/2015) [-]
Most likely a bit of both biological and environmental stimuli.
en.wikipedia.org/wiki/Biology_and_sexual_orientation
en.wikipedia.org/wiki/Environment_and_sexual_orientation

Make sure you use the references at the bottom and NOT the actual wiki articles
#4276 - anon
Reply 0
(03/09/2015) [-]
Does math count as science? I hope so. I really really am having trouble with calculus. I'm typically pretty good at math but I am just not grasping this kind of stuff. There is one problem that I have to solve on the board in class and I really don't want to blow it.

Anyone here good at calculus and can walk me through this problem? And if all else fails just show me how its done?

Find derivative up to order three ( y prime, y prime 2, y prime 3)
y = radical(x+2)(x-3)

If my explanation of the question isnt clear please let me know.
THanks in advance!
#4299 to #4276 - phtholognyrrh
Reply +1
(03/12/2015) [-]
science is watered down applied mathematics
#4276 - keeperman
Reply 0
(03/07/2015) [-]
hey has the euler trail has been cracked dono if this fits in this board
#4271 - ronjeremysweiner
Reply 0
(03/06/2015) [-]
Based on the idea of all life being descended from a one celled organism
And evolution being an extremely long process, is it actually possible for a single cell orgamism to have evoled into something as complex as what we are?
Is it more likely there are multiple "starting points"?
#4274 to #4271 - nimba
Reply +1
(03/07/2015) [-]
About starting points: It's not impossible, and there is genuine debate over it. Mechanisms of abiogenesis have been posed and some are convincing enough, but the pathway between expansive and reproductive organic structures and the first recognisable organisms is hazy. Obviously there are no fossil remains of this period and, because of the likelihood that protoorganisms were protein controlled rather than nucleic acid controlled means that they can't be teased out from existing DNA. I believe personally that the length of time between then and now could be sufficient to not require multiple starts.
Here's something that might help you understand multicellularity: Multicellularity is essentually symbiosis. Each of the cells in your own body is an individual organism that 'could' live in isolation. Indeed, there are many symbiotes from other species that are necessary for you to function as a single multicellular organism, they are as much part of the multicellular system as any of the human cells in you.
Multicellularity was probably driven way back by predation - the predatory cells had to be bigger than the prey cell in order to engulf it and this could be achieved by symbiosis with a fellow predatory cell. This put a drive on autotrophs to become bigger to avoid predation now - essentially a symbiosis facilitated size arms race between predators and prey.
#4281 to #4274 - schnizel
Reply +1
(03/10/2015) [-]
ni
gg
er
#4282 to #4281 - nimba
Reply 0
(03/10/2015) [-]
Comment Picture
#4275 to #4274 - nimba
Reply 0
(03/07/2015) [-]
To ramble on:
Cancer is an amazing example of this. When a tumour forms it represents the cancerous human cells identifying the rest of the body as a competitor. They, unlike the symbiotic bacteria in your gut and on your teeth, are opposed to the multicellular system - it's survival of the fittest and the tumour is operating like a novel organism where the system is full of resources to be taken regardless of the detriment to the host - they move from symbiosis to parasitism.
#4273 to #4271 - sugoi
Reply 0
(03/06/2015) [-]
Why would there be more starting points?
Like what's your basis for this theory? Humans sure is complicated we must have had a head start?
#4272 to #4271 - dehumanizer
Reply 0
(03/06/2015) [-]
nope
#4267 - alhemicar
Reply 0
(03/05/2015) [-]
Can anyone solve this problem?
A cylinder with a diameter of 5 cm and a weight of 500 g floats vertically in a fluid of a density of 1.8 g / cm3. If the roller is pressed from above, it dives into the liquid and begins to oscillate. Determine the period of the oscillation of the cylinder.
#4263 - magnuskasparov
Reply 0
(03/04/2015) [-]
Are there any engineers here? I was wondering how much of the math you learned do you use.
#4290 to #4263 - anon
Reply 0
(03/11/2015) [-]
Depending on which field to go to, it narrows down in uni with postgraduates.
#4258 - tocho ONLINE
Reply -2
(03/02/2015) [-]
Somebody should get a gecko and name him Mc.Geck
#4255 - sideism
Reply +1
(03/01/2015) [-]
do gay people masturbate to straight porn the same way straight people masturbate to gay porn?

questions like this keep me up at night....
#4257 to #4255 - nimba
Reply 0
(03/01/2015) [-]
I don't think I see much gay porn to tell the truth IDK bout you
#4249 - perform
Reply -1
(02/27/2015) [-]
What the fuck's up with the dress that everyone's talking about?
#4301 to #4249 - mvtjets ONLINE
Reply 0
(03/12/2015) [-]
I've heard all about the "perspective" thing and how the dress will change for some people every time they look at it, but I just can't look at it as blue and black no matter what.

I mean, the picture is actually light blue and brown, but that still isn't very close to dark blue and black.

I think people are exaggerating when they say it's black and blue TBH
#4268 to #4249 - anon
Reply 0
(03/06/2015) [-]
It's about how people perceive colours. Some see it blue and dark, while others see it as yellow and white.
#4254 to #4249 - nsfwcontent
Reply 0
(03/01/2015) [-]
#4251 to #4249 - sugoi
Reply +2
(02/28/2015) [-]
On February 25th, 2015, Tumblr user swiked posted a photograph of a dress asking the science side of Tumblr to help identify its colors, noting that her friends were torn between it being white and gold or black and blue. Within 48 hours, the post gained over 400,000 notes.
#4248 - nimba
Reply +2
(02/26/2015) [-]
ITT: your most monumental fuck ups in a lab/ most monumental you've seen other people do.

My most embarassing was in 1st year where the demonstrator was speaking over the intercom and everybody was silent to listen to him. I was taking molten agar gel out of a water bath but shit was slippy. It broke the perfect silence with the sound of the agar bottle smashing in the water bath, resulting ~ 200 people watching me try to fish agar and broken glass out of other people's e.coli incubations.
In high school I saw a guy heating a beaker of acid on a tripod over a Bunsen. Basically he set the tripod up on top of his school tie, so when he made to move away he had a beaker of boiling hot acid coming at his face plus a lit Bunsen. I swear I saw the teacher's career flash before his eyes.
#4296 to #4248 - anon
Reply 0
(03/12/2015) [-]
Not quite as bad as yours but I always struggle to reach the top of burette tubes, being quite short. So this one time, I couldn't quite get it and ended up pouring half a beaker of HCl acid down my sleeve. Luckily it was fairly dilute but my arm was nice and stinging for about a week after.
#4256 to #4248 - anon
Reply 0
(03/01/2015) [-]
Was doing a destillation reaction in the lab, the type where you put a balloon with N2 on top of the reflux to change the internal pressure. It was a long, hot summer day so I was really eager to go home.
The reaction was supposed to be performed at 50° so the installation was put on top of a heater for an hour. When the hour had passed, I immediately took the reflux away to start cleaning up. I took the reflux from the heater, out of the fume cabinet, while standing next to a big window (with the summer sun shining brightly), the sudden changes in the environment made the balloon explode, caused an internal pressure drop, forced a large quantity of the product (i'm not sure what it was, but it wasn't healthy) outward and on my face and even into my mouth, as I gasped at the explosion.
The next second I realised what had happened, and I turned aside towards the washing bin to spit the stuff out, but 3 of my female collegues were standing in front of it, as they were chatting about the experiment and had seen what happened. I didn't want to spit on the ground but it tried to get it out of my throat so I regurgitated in my mouth (like you would do with a flem or something similar). To my collegues, however, this sounded like the product in my mouth was burning my throat, so they started screaming.
In the end there was no lasting damage, and the potential dangerous elements had been denatured during the process.
The irony of it all, however, was that 30 minutes before this happend, we had an inspection by the head of the Chemistry department to check wether we were working in accordance to health and safety regulations, and we all received this little note that congratulated on our exemplary work.
#4253 to #4248 - dreadnaor ONLINE
Reply +1
(02/28/2015) [-]
Tested pH inside my mouth once. Used some paper thingies from back when Stalin was alive. Got a 11 - 12 pH score. Never kissed a girl in highschool because of the fear of chemical burns.
#4259 to #4253 - redandgreen
Reply 0
(03/02/2015) [-]
tingly!
#4252 to #4248 - berengar
Reply 0
(02/28/2015) [-]
I don't have any horror stories, the most I have seen is people almost lighting themselves on fire.
#4245 - michaelbates
Reply 0
(02/26/2015) [-]
Everyone, I need some advice.

I am currently doing organic chem research with a professor at the university that I attend. There are three other students working with me, so there are four of us in total.

To get to the point, both groups are charged with performing alcohol protection reactions. We are to perform these reactions with 200mg of starting material until we can get the desired product in at least 75% yield. Once we break this initial barrier, we are allowed to start working on a 500mg scale. Our goal, as of now, is to build up a substantial reserve of this product.

My partner and I are performing this alcohol protection on 2-hydroxy-4-methoxy-acetophenone. The general steps we perform are as follows:

1) Dissolve 1.5 equivalents of NaH in THF
2) Add starting material, stir solution for 30 mins at 0 celsius
3) Add 1.5 equivalents of benzyl-bromide, stir for 1 hour at 0 celsius
4) Stir for 2 hours at room tempearture

This reaction should be rather easy to pull off, but my partner and I are struggling. We have worked in the lab Monday through Friday for the entirety of February, and we have no product. Meanwhile, the other group has already built up a large quantity of their product. To be frank, its rather embarrassing, and my partner and I feel like complete idiots. We have no clue why this reaction isn't working. I have read a number of different methods people have used for alcohol protection reactions with benzyl-bromide. Some experiments suggest reflux and others suggest stirring for anywhere from 16-35 hours.

So my question, what do you guys think I should do? Has anyone done these type of reactions before? If so, how long did you let these reactions run for?
#4232 - depressedpuppey
Reply -1
(02/25/2015) [-]
Guys i need halp.
Im assigned to do a presentation about time.

you guys got cool facts and shit?
#4297 to #4232 - vgmddg
Reply 0
(03/12/2015) [-]
Human beings are scary.
#4239 to #4232 - nimba
Reply +4
(02/25/2015) [-]
Don't Hug Me I'm Scared 2 - TIME Time is a tool you can put on the wall or wear it on your wrist. The past is far behind us, the future doesn't exist.

various crap I've heard: There is no single indivisible unit of time, even the smallest fraction of a second is a continuum. Neuroscientists have suggested that the idea of 'now' lasts about three seconds given the way we perceive time. The idea that time moves faster as you get older is possibly caused a sort of relativism; to a 10 year old a single year is very long because it constitues one tenth of their entire life, whereas to a 50 year old it would be a mere fiftieth.
Here's some generally less related facts
www.did-you-knows.com/did-you-know-facts/time.php
#4244 to #4239 - depressedpuppey
Reply 0
(02/26/2015) [-]
Thanls mah nigga
#4237 to #4232 - coronus
Reply 0
(02/25/2015) [-]
Well , I know that it keeps on slippin' into the future.
#4238 to #4237 - coronus
Reply 0
(02/25/2015) [-]
sorry
#4231 - spartusee
Reply 0
(02/25/2015) [-]
Can someone help me with this trigonometry problem, I don't understand the concept.

You need to login to view this link
#4233 to #4231 - coronus
Reply 0
(02/25/2015) [-]
You'll want to make a right triangle.

-cosin of an internal angle is equal to the ratio of the adjacent side over the hypotenuse
-Sin of an internal angle is equal to the opposite side over the hypotenuse
-Tan is opposite over adjacent

Use these to construct a 30-60-90 right triangle with known sides, using the ratio you're given with the Pythagorean theorem to find the length of the side opposite the 30 degree angle.

from there it's just plug and chug for the various identities, since you'll have a solved right triangle.
#4230 - anon
Reply 0
(02/25/2015) [-]
I don't understand this, can I get some help with it.

[url deleted]
#4226 - luigipimp
Reply 0
(02/24/2015) [-]
if the amount of oxygen WAS doubled, would humans get bigger too or just bugs and spiders?
#4246 to #4226 - alltimetens
Reply 0
(02/26/2015) [-]
I think that the greatest benefit from a doubling of atmospheric oxygen composition would be the fact that we'd have more efficient fuel.
#4240 to #4226 - nimba
Reply 0
(02/25/2015) [-]
Bugs and spiders would get bigger because they gain oxygen by diffusion whereas we use something more like active transport on a gross scale with our lungs. As for the bassmaster's idea about developing a less efficient respiratory system that would take a geological length of time and I would wonder whether it would really happen at all considering that survival of the fittest has an increasingly small impact on human evolution. We'd be unilaterally more capable at things like sports and manual labour, for a start, showing much better endurance and recovery. We wouldn't increase in size like the spiders probably, but our upper limit for muscular capacity would potentially increase somewhat and there would be some impetus for increased vascularity but any evolutionary change would be unlikely to occur if at all in my opinion.
#4228 to #4226 - thebassmaster
Reply +1
(02/25/2015) [-]
I would imagine that humans would develop less efficient respiratory systems due to the ease of respiration the extra oxygen would facilitate. Oxygen isn't a growth hormone, and the current biological systems of not just humans but all animals are evolved, and therefore best suited for the size they are currently and for utilizing the ratio of oxygen currently in the atmosphere. Advantages like more oxygen won't change much. For example, the average human today is much larger than our hunter-gatherer ancestors due to improved healthcare and nutrition, but you will never see human beings much larger than Wadlow(tallest human ever), because their bodies systems cannot support such a size(primarily the skeletal and circulatory systems), and there is no evolutionary advantage to being larger than we are at this point.
#4216 - kebabs
Reply +1
(02/24/2015) [-]
Assniggers, I have found the solution to all.
Fix a coil of some turns in some depth in the vagina which will be connected to a rectifier and a small vibrator which would be directly touching the surface of the vagina deep inside (~9inch). Now we attach a magnet of suitable strength to a man with small penis and then the sex begins.
Working:
The thrusting motion of the man with small penis will create a change in magnetic flux which will induce an e.m.f in the coil in the vagina, this a.c will be converted to d.c in the rectifier, amplification may be needed so we connect an amplifier to it as well. Now this amplified current will reach the vibrator which will simulate the vagina deep inside.

It's a win-win situation for a guy with small penis and the girl who is in love with a guy with small penis. Thoughts?
#4241 to #4216 - nimba
Reply +1
(02/25/2015) [-]
The average vagina is about 4/5 inches long last time I checked, if you put something nine inches deep it's going to be inside the uterus - which would be... uncomfortable. Additionally the vagina, like the penis, is most sensitive towards the extreme end to the extent that orgasm can be achieved digitally up to just the second knuckle which is usually about 1 1/2 inches. With a shorter, less girthy cock there is a greater prerogative to angle towards the area of sensitivity, commonly 1-2 inches inside on the superior surface to contact with the base of the clitoris.

Besides, vibrating cock rings exist.
#4217 to #4216 - funnyjunkelite
Reply 0
(02/24/2015) [-]
So if you set a giant magnet somewhere and a women have this, it'll cause all of them to have orgasms?
#4220 to #4217 - kebabs
Reply 0
(02/24/2015) [-]
Let's put a key to the rectifier.
#4221 to #4220 - funnyjunkelite
Reply 0
(02/24/2015) [-]
What about babies? a mecha vagina might sterilize it
#4243 to #4221 - nimba
Reply 0
(02/26/2015) [-]
I heard of a contraceptive coil that's made of copper and kills semen, look it up. Called an IUD coil I think.
#4222 to #4221 - kebabs
Reply 0
(02/24/2015) [-]
Isn't that a good thing. That's totally a good thing.
#4223 to #4222 - funnyjunkelite
Reply 0
(02/24/2015) [-]
no babies=no human race
rip humans
#4224 to #4223 - kebabs
Reply 0
(02/24/2015) [-]
Small pay for huge pleasure.
#4218 to #4217 - funnyjunkelite
Reply 0
(02/24/2015) [-]
A woman*
#4219 to #4218 - funnyjunkelite
Reply 0
(02/24/2015) [-]
Just take out the A


goddammit
#4215 - davyjonesbooty
Reply +1
(02/24/2015) [-]
I think this belongs here...

So I was reading the Keen Software House AMA on reddit (Space Engineers dev team, www.reddit.com/r/IAmA/comments/2ww6ib/we_are_keen_software_house_developers_of_space/ ) and a lot of people were asking about the "Super Secret AI Project" announced a few months back, thinking it would have something to do with NPCs. Apparently not. According to this link given to us by the dev team www.zive.cz/clanky/prednaska-o-vyzkumu-umele-inteligence-v-keen-software/sc-3-a-177121/default.aspx open in Chrome for translation they're trying to make a full blown AI that learns like a human does.

What does /science/ think?
#4242 to #4215 - nimba
Reply 0
(02/25/2015) [-]
Read up about the foldit app. It lets users resolve 3D protein structures and records the users' methodology. It then gives the methodological data to an AI so it can ape human problem solving skills to fold proteins on its own. It's not so much an AI as a database of canned 'human' responses but the difference seems academic to me.
#4235 to #4215 - coronus
Reply 0
(02/25/2015) [-]
it's an old problem.

Computers suffer from a complete dependence on concrete and discrete data in all decision making applications. Currently , both logical and statistical AI fail to achieve human like learning simply because a program must always default to quantifying data in a manner particular to the logical systems upon which computers are built. This gives rise to visual recognition software that can be tricked and trained to group objects into categories that don't belong together,such as a particular pattern of vertical lines being recognized as a school bus.

Because even the must advanced AI has to take data and simplify it into computational values in order to "understand" and process the information in its emulated or observed environment, I believe that an AI might never learn like we do.

Additionally, humans learn to categorize and make judgments about environments and stimuli based on a rather fuzzy understanding of statistics that has thus far been incredibly difficult to equivocate mathematically, because it involves a certain ability to deal with uncertainty by pulling together past information with reasonable guesswork.

While computers are good at " remembering" information, the main component of human learning that is so critically different is the ability to spontaneously integrate guesswork and creativity into solutions and uncertain situations. Computers lack the ability to produce novel insights, since even the best AI lacks true personal agency and motivation, making them fundamentally incapable of the type of individual thought that leads to learning and problem solving in humans.

In short, we might get to the point where an AI possesses the emergent property of individual agency and creative thought, but it's an extremely difficult task to conquer from the current ground up approach. It's going to require some of the current studies in systems neuroscience to produce data on individual neurons and meso-cortical activation patterns that are involved in learning, as well as future studies in computational modeling on those same systems.