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/sci/ - Science, Technology, Engineering, and Mathematics

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New Textbook/Book Request Thread deadbabies ## Mod ## 13/08/25(Sun)06:03 No. 15270 ID: f34135 [Reply] Stickied

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First off, hello there, I'm deadbabies, and I will be taking over as /sci/ moderator. Rules will remain the same. Please use the report function if you see posts that violate the rules, but also do not abuse it.

I have officially expanded the scope of /sci/ a bit. You may discuss Science, Technology, Engineering, and Mathematics here now. No science is discriminated against as long as it's of the peer-reviewed variety. If someone wants to discuss Anthropology or Social Science, by all means, let them. If you do not like it, just don't post in the thread.

The IRC channel #/sci/ is now (finally) re-registered and I am running as operator on here. Feel free to stop by and say hi. I do leave my computer idling on IRC, so check back or leave me a message if you have any ideas, suggestions, or just want to tell me off. You can get onto #/sci/ by joining the server irc.7chan.org at port 6667. You can also use SSL at port 6697 but you will have to set your client to accept invalid certificates.

ADDITIONALLY and IMPORTANTLY I have had several requests on IRC regarding the old Ebook FTP that we used to have. Unfortunately, the mod who ran it entered the military and no longer runs or maintains it. I have no plans to make another one, but if one of you guys would like to, by all means advertise here.

That being said, I'm just going to leave this link here:


You may find what you seek here.

I will be unstickying the old ebook/source articles thread. Please post any new ebooks/source articles here, and feel free to post any working links from the old thread there; I will eventually be deleting it.
Message too long. Click here to view the full text.

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Solutions Manual to E&M, 3rd Edition by Purcell Anonymous 16/11/19(Sat)00:05 No. 16384 ID: 1ae570

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Looking for the the solutions manual to Electricity and Magnetism, 3rd edition by Purcell and Morin. The problems are much more difficult and numerous than in the previous two editions, making it one of the best problem books on the subject. Was able to find the solutions to two analogous books in Classical Mechanics:



Sadly, all my searches for the solutions to the E&M book have been fruitless. It's the last manual that I need to complete my collection.

Homosexuality, could it be an anomaly in brain developement? Dr. Nick Riviera 15/02/05(Thu)04:59 No. 16039 ID: 8ec688 [Reply]

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Hi guys, to begin I just want to make a couple of things clear.

- This thread is NOT about discrimination of homosexuals.
- This thread is NOT about considering homosexuality as disease.
- This thread is for pure scientific discussion.

Well, let me begin by telling you that I'm a med student and a embriology assistant at my university and I'm not a native english speaker, so you may encounter some grammatical errors in the text, but you'll get the point.
This whole dilemma began two weeks ago, when my brother told my family that he is gay. It was quite a shock, not because of the fact of him being gay but because he doesn't fit the gay man stereotype. He's a big dude, loves sports, bearded, the true definition of what some call "manly man". We accepted him, of course, and I have to say I've never seen him happier.
But after a few days I began to think, was he always gay? Did he decided to be gay? Why now? These questions started lingering in my mind. So I went to talk with my him about it.
He told me that he always has been, for as long as he remembers. Nothing has changed about him, except for his sexuality (for us, not for him haha). So that got me even MORE questions. Why are some gay men that are like extremely feminine? Why are some gay women extremely masculine? Why are gay guys like my brother who don't appear to be gay? Why do some gay people feel like they are traped inside the other genders body and need to get medical treatment (sex change surgery, hormone therapy) and why others don't?And why are there women like that too? Why many species, whose main goal is to survive (actually this is every species main goal, it's literally in our DNA), has certain individuals who are the contrary to this?
So I decided to tackle all these matters from a scientific point of view? What if during the development of the lymbic system (the part of the brain which controles emotions, memory, sexual desire, etc.) something doesn't go as it should?
So after I thought of this I told myself I couldn't be the first one to ask myself these questions. And of course I wasn't in a world with 7 billion people so thanks to the magical power of the internet I managed to get a cool text about the subject. I took some paragraphs which I thought were the most interesting, still I'm leaving the link (please don't take the text as discriminatory, it's merely scientific, it refers to homosexuality as an anomaly in brain developement because seen from a medical point of view it is, still doesn't mean it's moraly wrong).

"..the body and the brain first become sexually differentiated at about the third fetal month. Prior to this age, although genetically male or female, the fetus is physically/sexually-neutral. With the formation of the testes, and the secretion of testicular androgen, target ti Message too long. Click here to view the full text.

28 posts and 1 image omitted. Click Reply to view.
Anonymous 18/06/25(Mon)02:20 No. 16664 ID: a521d4

For the longest time, people have been saying yes. Kids ignore them because their foster parents (school, country, media) claim otherwise. Only corrupt dreamers think otherwise.

Anonymous 18/06/28(Thu)13:24 No. 16669 ID: c6e9b2

Who cares? Homophobes causes much more problems than the opposite.

Anonymous 18/11/12(Mon)09:57 No. 16720 ID: 0dfe17

wow faggots

Genetic Philanthropy - Genetophil Anonymous 18/09/29(Sat)17:53 No. 16698 ID: ed3f35 [Reply]

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Why not create a charity to raise IQs in third world nations? Some leading experts say genetics account for 80% of IQ by the time you're 18. The average IQ is dropping worldwide. Would it be ethical to increase IQ through genetic engineering?

4 posts and 1 image omitted. Click Reply to view.
Anonymous 18/10/08(Mon)20:26 No. 16704 ID: be6f8f

I think you have cause and effect inverted. It's not that rich people want poor people so they can apply certain economic policies, it's that certain economic policies applied by rich people cause other people to be poorer. Basically, a society where some participants believe they should get wealthier without end inevitably leads to economic inequality.

Anonymous 18/10/22(Mon)09:20 No. 16710 ID: 848b2c

IQ is largely irrelevant to economic productivity and almost COMPLETELY irrelevant to social power; just look who we have in the White House if you're tempted to disagree (or who we MIGHT HAVE HAD, if you still do). Take a black child out of poverty and stick them in a wealthy Western household with a proper education and a diet composed of more than literal garbage, and they will grow up to be a productive adult.

That said, an IQ test measures little more than your proficiency at taking IQ tests. It was NEVER a measure of intelligence; it was a measure of educational achievement as a tool to focus on struggling schoolchildren with poor learning ability, and at best has a tenuous connection with adult intelligence except in extreme cases (like profound retardation: <20IQ). Studies have shown that people with higher IQs don't achieve more as adults but for statistically insignificant amounts.

So you could do this, sure, but nothing would change. The only thing that will is waiting for most of them to die, and then raising the living conditions up to a Western standard for the survivors. Doing it BEFORE letting them die is more humane, sure, but will probably collapse the global economy by the end of the century, likely leading to widespread war and the end of civilization. There's just too fucking many of them.

Anonymous 18/11/10(Sat)12:56 No. 16719 ID: c6e9b2

I cant' totally agree. Yes, most westerners wouldn't just breeze trough the life in the average african village. Stirling paints in Islands in The Sea of Time a vivid picture of the back-breaking work needed to grow your own crops.

Their intelligence may help them work more organized, but the raw strength is what matters. - As in all agrarian societies.

But in modern societies general intelligence (g) is more important than raw strength. And there's no link between general intelligence and industriousness (i).

I score high on g, but really low on i (just ask the tax authorities). And you can never disregard the society someone lives in.

Deductive, inductive or abductive? Anonymous 18/07/24(Tue)12:27 No. 16679 ID: c6e9b2 [Reply]

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Hello /sci/!

Yesterday when I took a walk, I saw a bunch of huge plastic containers by the roadside in a shallow natural pit.

I considered it to be a trash dump.

What kind of reasoning did I use. Deductive, inductive or abductive?

And if I used the other two kinds of reasoning, would I reach the same conclusion? And how would I use them?

5 posts omitted. Click Reply to view.
Anonymous 18/10/29(Mon)10:50 No. 16715 ID: be674a

>I assumed OP was talking about plastic dumpsters
There is no such thing as plastic dumpsters. They make them out of steel because plastic in that size is not structurally sound enough. Also, why would there be dumpsters on the side of the road in the first place? It still raises the same question of who put them there, and for what purpose.

Anonymous 18/11/01(Thu)22:02 No. 16716 ID: 80b009

>There is no such thing as plastic dumpsters.
All you needed to do was search "plastic dumpster" in Google Images to fact-check yourself.

>Also, why would there be dumpsters on the side of the road in the first place?
The point of a dumpster is that a garbage truck can pick it up and empty it. Garbage trucks generally drive on roads, so the logical place to put a dumpster, if it's desirable that a garbage truck can reach it, is as close to the road as possible.

Anonymous 18/11/07(Wed)07:46 No. 16718 ID: dc714c

>they actually do make plastic dumpsters
Color me surprised Pedantic: they have a plastic shell and steel reinforcement. And while you're technically correct, it doesn't change that those that I saw are smaller containers, generally for household rather than commercial/industrial use. Most people do not BUY dumpsters; they rent them from the garbage company who picks up the garbage from them on a set schedule, and those dumpsters ARE made of steel. 99% of the dumpsters you're going to see are made of metal; personally I've never seen one of these plastic ones. You're begging to put holes in the fucking thing because people throw concrete chunks and shit in there.

I'm sure there's some retard online out there selling dumpsters made of wood or who has made one of papier mache as an art project. But that changes nothing. OP never stated "dumpsters" to begin with, which would be fairly obvious given that they have a distinctive shape. So one could conclude these "containers" likely were not dumpster-shaped.

>the logical place to put a dumpster, if it's desirable that a garbage truck can reach it, is as close to the road as possible
But not randomly on the side of a road where there's nothing else! There's no trash sitting around there to put IN the containers in the first place. If there were a warehouse or a restaurant right next to it, then it would make sense. But that definitely would not be a "trash dump", it would be "a little concrete pad on their property where sit the dumpsters".

dtyjhty HELP yutyjtry 18/11/03(Sat)21:11 No. 16717 ID: c2ed95 [Reply]

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Error: An OpMode with the name 'Pushbot: Auto Drive by Encoder' is already registered; ignoring duplicate opmode.

Chemistry Anonymous 18/10/22(Mon)12:42 No. 16713 ID: eb4831 [Reply]

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Alright, so some dude is trying to determine the atomic mass of 3g Tellur and ends up with 3,475 TeO2. How big is the relative atomic mass of Tellur (atom. mass of O = 16)

Starting Math Major soon, how to approach? RedRobin9688 18/07/14(Sat)11:25 No. 16675 ID: 241c58 [Reply]

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I move in 8/5/18 and intend to Major in Mathematics, there are four options (Pure, Applied, Applied Stats, Actuarial) which should I formally choose to actually succeed? Should I double major? and if so what in? I'd appreciate the help, I don't want to move in with the parents after school.

1 post omitted. Click Reply to view.
Anonymous 18/07/20(Fri)20:31 No. 16678 ID: 48d322

Acturial is like accounting sort of. I don't know how to descrive.

Anonymous 18/09/28(Fri)21:03 No. 16697 ID: 4f487e

Acturials are the end boss of accountants.

Anonymous 18/10/22(Mon)09:24 No. 16711 ID: 848b2c

Actuarial are accountants for companies, rather than for individuals. They deal with statistics, mostly, to determine what might happen with a given set of starting variables. Most visibly, actuarial tables are what these people produce for life insurance companies, so they can guess at what age you're likely to die (based on sex, height/weight, blood tests, diet, lifestyle, and increasingly: genes) and adjust your rate accordingly so that they are most likely to profit.

EXPERIMENT Anonymous 18/10/19(Fri)20:34 No. 16708 ID: 9166cf [Reply]

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Anonymous 18/10/20(Sat)04:16 No. 16709 ID: 1e5fb7

God be with you on that shit man.

silver fulminate Anonymous 18/10/13(Sat)03:31 No. 16705 ID: 418128 [Reply]

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It is not called a "high explosive" for nothing. I Saw a video on YT of a guy gripping a chunk and throwing it.. I was not so lucky. Mine just blew up on my desk from the slightest friction!

Anonymous 18/10/13(Sat)03:45 No. 16706 ID: b5377a

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You should blow up a police station.

Binomial Irgendwas Anonymous 18/09/11(Tue)02:39 No. 16694 ID: f54f31 [Reply]

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I have a question with regards to what I would call a particular object that enumerates the elements of a binomial coefficient. Let me explain the thing first.

Lets say I have 6 elements and I'd like to choose 4 of the stupid things. The binomial coefficient tells me that there are 15 of these groupings. I.e. these:
I would like to enumerate over these groupings; and I have an object that does.

My question then is, what would I call the thing that enumerates over those groupings?
Binomial Enumerator?

Anonymous 18/09/11(Tue)18:27 No. 16695 ID: be6f8f

The technical term for each of those "groupings" as you call them is "combination". The action of picking combinations is usually called "choosing" (e.g. 6C4 is read "6 choose 4").
So you could call the enumerator "combination enumerator", "combinator", or "chooser". I think those are all acceptable names.

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