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Friday, April 13, 2018

If extra wings seen on biplanes add more lift and maneuverability, why don’t we add them to modern planes or jets and have them built into the airframe like we do today?

If extra wings seen on biplanes add more lift and maneuverability, why don’t we add them to modern planes or jets and have them built into the airframe like we do today?


If extra wings seen on biplanes add more lift and maneuverability, why don’t we add them to modern planes or jets and have them built into the airframe like we do today?

Posted: 13 Apr 2018 05:05 AM PDT

Does the moon or other planets have magnetic poles?

Posted: 12 Apr 2018 10:51 PM PDT

Would we be able to use a compass there like we do here?

submitted by /u/frickfrackcute
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Why are cooling towers shaped the way they are?

Posted: 13 Apr 2018 04:28 AM PDT

Power plants or large factorys all have the same shape of their cooling tower. The radius is smaller in the middle and widing up on top again. Whats the reason we dont use the same radius everywhere or it only gets smaller higher up.

submitted by /u/IntenSIEF
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Does body language have 'dialects' as such?

Posted: 13 Apr 2018 05:40 AM PDT

What exactly happens when Polyurethane foam is formed?

Posted: 13 Apr 2018 03:20 AM PDT

I am currently doing my mechanical engineering dissertation on making structures using polyurethane foam, I have no background in chemistry and reading through many papers on polyurethane I find them hard to follow sometimes. I have searched through many papers to try and find what is going on but I cannot. Basically I have seen studies whereby the PU foam is formed within a vacuum, however in my experiments I have tried to form PU foam within a bag and it does not expand anything like it does when open to the air. Can anyone explain what is going on and why air is needed? Or am I missing something ? I am using 2 part pour-able foam.

TL:DR Polyurethane 2 part foam is not expanding properly when not exposed to air, why?

submitted by /u/teegfit1
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Do birds have tastebuds?

Posted: 13 Apr 2018 05:32 AM PDT

What draws them to French fries, potato chips, and other "snacky" foods?

submitted by /u/meganzin
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Why doesnt AIDS burn itself out?

Posted: 13 Apr 2018 06:04 AM PDT

Shouldnt there be a point where AIDS kill all of the lymphocytes that are its host, therefore not being able to reproduce anymore and dying. I.e burning itself out.

submitted by /u/nanaro10
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Can current models accurately predict the temperature of super nova stars just before they explode and create a black hole?

Posted: 12 Apr 2018 10:37 PM PDT

can the temperature be predicted as a star implodes, is there evidence to support how accurate the predictions of those temperatures are?

submitted by /u/CajunKush
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If my weather app breaks down the probability of precipitation by hour, how do I determine the probability for the day?

Posted: 13 Apr 2018 05:38 AM PDT

Right now it says 40% chance for the next two hours, 50% for the next hour, 56% for the next two hours, and then 30% for the rest of the evening.

If each of these is independent, does that mean the probability for the whole day is very high? Or is the whole day probably still around the 50% range?

submitted by /u/pm_me_ur_demotape
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Why can't processors guarantee calculation of a known problem in constant length of time?

Posted: 13 Apr 2018 04:41 AM PDT

All commercial airplanes basically have the exact same design; is that by necessity or happenstance? Did it really have to be that one way?

Posted: 12 Apr 2018 10:25 PM PDT

How do animals without parental figures know what species to mate with?

Posted: 12 Apr 2018 01:19 PM PDT

Differing forces in different reference frames?

Posted: 13 Apr 2018 05:06 AM PDT

Posted the question in the r/Physics thread but haven't gotten any answers so figured I might try my luck here.

A question that has been confusing me for a while now:- Firstly, we consider the day-to-day frame of reference that we normally think about. We are pulled down by a gravitational force mg downwards, and pushed up by the normal force of same magnitude provided by the ground - hence we stay stationary on the ground with no acceleration. However, if we look at the entire Earth as a reference frame, the Earth is rotating on its axis and we are rotating on it with the same angular velocity. Then clearly we cannot have the normal force N=mg, since in that case we would have no net acceleration and will not rotate in a circle around the Earth's axis.

So this is the part where I get confused about what forces are in play here. I think the normal force by the Earth in that reference frame must not be opposite to the gravitational force, but rather their vector sum should point towards the Earth's rotational axis to provide us with the centripetal acceleration. However in that case, why does the same(?) normal force appear to be acting in different directions in different reference frames? I also might be wrong in my analyses of forces present and there is another (pseudo?)force that can help explain this problem.

submitted by /u/IFTClerk
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Why does the Pauli Exclusion Principle apply to fermions but not to bosons?

Posted: 12 Apr 2018 12:53 PM PDT

Can a x86_64 CPU be designed to run code meant for ARM_64?

Posted: 13 Apr 2018 12:43 AM PDT

Unless I got something wrong a x86_64 should be able to handle all the instructions that an ARM_64 can, just at reduced speeds.
Would this even worth doing?
Or would it be just as fast to emulate an ARM_64 CPU?

submitted by /u/Starf4rged
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Could you make a Silicon version of Graphene?

Posted: 12 Apr 2018 01:43 PM PDT

Would it be possible to have a silicon (or other element in that group/column) equivalent of graphene where the atoms are arranged in the same manner? I imagine this substance would have similar properties to the carbon version.

submitted by /u/TheWierderOne
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Why do some plants have colorful (not green) leaves in the spring and summer and not just in the fall?

Posted: 12 Apr 2018 11:33 AM PDT

Something like a japanese maple comes to mind

submitted by /u/Forestpotato
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If there is an absolute cold, is there an absolute hot?

Posted: 12 Apr 2018 04:43 PM PDT

Is development of muscle memory partially performed outside the brain?

Posted: 12 Apr 2018 09:01 AM PDT

I'm aware that many changes occur in the brain when developing muscle memory, but I do not know to what degree the part of the somatic nervous system outside the brain changes and whether or not those changes are largely significant to performing a particular motor function. If you were to learn to play the guitar but, after doing so, only retained the neural development done directly in your brain, would you still have the capacity to play? I understand this is a hypothetical question to a degree, but the information the answer provides is relevant to the more concrete question underneath.

submitted by /u/ZaxasT
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Thursday, April 12, 2018

Why do certain flavours go well together? E.g. chicken/coleslaw, tomato/mozarella, spinach/garlic, walnuts/honey, tuna/mayonaise?

Why do certain flavours go well together? E.g. chicken/coleslaw, tomato/mozarella, spinach/garlic, walnuts/honey, tuna/mayonaise?


Why do certain flavours go well together? E.g. chicken/coleslaw, tomato/mozarella, spinach/garlic, walnuts/honey, tuna/mayonaise?

Posted: 12 Apr 2018 03:01 AM PDT

Why does my hearing go muffled when I get a headrush from standing up?

Posted: 11 Apr 2018 11:49 AM PDT

Giraffes only sleep a cumulative 30 minutes per day. They take brief, minute-long naps throughout the day, all while standing up. How are they able to function without large amounts of rest?

Posted: 11 Apr 2018 01:24 PM PDT

In quantum tunneling, if an electron has energy 2eV, why can it escape if 5eV is the energy to escape? Where does this energy come from?

Posted: 12 Apr 2018 05:17 AM PDT

If the Milky Way is moving through space, is it orbiting something bigger?

Posted: 11 Apr 2018 12:12 PM PDT

Why is voltage and current specified in electrical equipments?

Posted: 12 Apr 2018 04:41 AM PDT

My phone charger, for example, has an output of 1.55A at 5V. My understanding is that Voltage causes current to flow. Current is the rate of flow. So in the case of my charger, does the voltage here matter? Why is it specified? To calculate power? What if I have another charger that's 1.55A at 10V? What does that mean? Surely, my phone isn't getting charged faster because they're both 1.55 coloumbs of charge per second.

submitted by /u/KillCq
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Where does the fat go?

Posted: 11 Apr 2018 06:28 PM PDT

I recently lost 20 pounds (yay me!) and I wonder... Where did it go? Did I pee it out or did it change into something else?

submitted by /u/Mamashake
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How does mica rotate plane polarized light by 90 degrees?

Posted: 11 Apr 2018 09:06 PM PDT

I have a few pieces of iolite that allow me to demonstrate this property really effectively, but I don't have a good explanation for how the mica's crystal structure results in the rotation of light. I understand how a crystal's optical properties are determined by its symmetry and structure, and that mica is extremely anisotropic (hence its cleavage), and the pleochroism exhibited by iolite is intuitive enough to me, but the rotation caused by mica isn't quite clicking for me.

submitted by /u/ExsolutionLamellae
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What mechanism prevents hernias from healing on their own and necessitating surgery?

Posted: 11 Apr 2018 07:24 PM PDT

What happens when you use Knuth's up-arrow notation with non-natural numbers?

Posted: 11 Apr 2018 04:26 PM PDT

Suppose you take Knuth's up-arrow notation. Using it on integers is easy: 3 ^ 3 = 33 = 27, 3 ^ ^ 3 = 333 , etc. But what happens if you place a fraction as the latter number? 3 ^ (1/3) is obviously the cubic root of 3, but what about 3 ^ ^ (1/3)? What if we place a negative number instead? Or a complex number?

submitted by /u/Apophyx
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Ask Anything Wednesday - Engineering, Mathematics, Computer Science

Posted: 11 Apr 2018 08:14 AM PDT

Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Engineering, Mathematics, Computer Science

Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical /r/AskScience post? No question is too big or small for AAW. In this thread you can ask any science-related question! Things like: "What would happen if...", "How will the future...", "If all the rules for 'X' were different...", "Why does my...".

Asking Questions:

Please post your question as a top-level response to this, and our team of panellists will be here to answer and discuss your questions.

The other topic areas will appear in future Ask Anything Wednesdays, so if you have other questions not covered by this weeks theme please either hold on to it until those topics come around, or go and post over in our sister subreddit /r/AskScienceDiscussion , where every day is Ask Anything Wednesday! Off-theme questions in this post will be removed to try and keep the thread a manageable size for both our readers and panellists.

Answering Questions:

Please only answer a posted question if you are an expert in the field. The full guidelines for posting responses in AskScience can be found here. In short, this is a moderated subreddit, and responses which do not meet our quality guidelines will be removed. Remember, peer reviewed sources are always appreciated, and anecdotes are absolutely not appropriate. In general if your answer begins with 'I think', or 'I've heard', then it's not suitable for /r/AskScience.

If you would like to become a member of the AskScience panel, please refer to the information provided here.

Past AskAnythingWednesday posts can be found here.

Ask away!

submitted by /u/AutoModerator
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How do Electromagnets Work with Conservation of Momentum?

Posted: 11 Apr 2018 07:06 PM PDT

I'm a grad-level physics major, but a couple of days ago I got asked a question that I still haven't been able to satisfy myself that I fully understand.

Suppose you have two solenoids, A and B, separated by some distance.
A is connected, generating a static magnetic field. B is not, and is a broken circuit (i.e. cannot sustain current at all).

I connect B, so that it is pushed outwards by A's field, and then immediately disconnect A so that it has no dipole moment. Because the field from B takes time to propagate, coil A will have zero dipole moment by the time the field "arrives", and so no reaction force will be generated. One object has been pushed, while the other has not, seemingly generating thrust from nowhere.

Time-varying fields aren't my strongest point, so I strongly suspect that what I'm missing is somehwere in the turning of the coils "on" and "off", i.e. that the changing fields in this window generates a non-zero Poynting vector, but this doesn't seem to grok with the symmetry of the problem.

submitted by /u/Sand_Fall
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Is the element Mercury named after the planet, or is the planet named after the element? Or are they related at all?

Posted: 11 Apr 2018 06:36 PM PDT

What reasons necessitate the imidazole ring in the base pairing of RNA/DNA?

Posted: 11 Apr 2018 04:38 PM PDT

Specifying: This is not asking 'why is there an imidazole ring in a purine'.

Rephrasing: What reasons prevent the phosphate backbone DNA/RNA from using ONLY pyrimidines in their base pairs?

Here are some things I could speculate possibly being the case:

Is there not enough variety in naturally occurring pyrimidines to support enough base pairs?

Is it because the hydrogen bonds between pyrimidines for whatever reason are either stronger or weaker than ideal for the various processes that depend on hydrogen bonds?

Is it that a pyrimidine base pair would, because of being of shorter length, end up twisting the backbone more than it wants to be twisted, and/or stacking too much closer to the other base pairs? (for processes that depend on the power necessary to untwist the helix, and overcome the stacking energy)

Is it that this configuration would not support the major and minor groove that becomes necessary in other processes?

I know I have yet to read further in depth, specifically, on the topics of pi stacking and the ultimate function or necessity of the major and minor grove.

Thank you

submitted by /u/RNA-curious
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CRISPR Cas9 - How does the Cell decide which repair pathway to proceed with?

Posted: 11 Apr 2018 03:02 PM PDT

I understand that Cas9 is an endonuclease that makes a nick in the DNA, but then how does the cell decide whether to proceed by non-homologous end-joining or homologous recombination?

submitted by /u/MaldororHollow
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Can strong wind influence the path (or the speed) of sound and light?

Posted: 11 Apr 2018 02:52 PM PDT

not sure if its a legit question or just dumb. but speed and sound travel through matter at a certain speed (i think). if that matter happens to be air, and if that air happens to be a strong wind, would this mean that it does get influenced?

submitted by /u/jokasi58
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What’s in the direct center of a black hole? When light and other various things get sucked into the black hole what happens to them? Are they crushed? What happens when something goes into a black hole?

Posted: 11 Apr 2018 11:56 AM PDT

Wednesday, April 11, 2018

Is it possible for a deaf person to have tinnitus? If so, how does it work?

Is it possible for a deaf person to have tinnitus? If so, how does it work?


Is it possible for a deaf person to have tinnitus? If so, how does it work?

Posted: 10 Apr 2018 09:43 PM PDT

Is there a triple-point with plasma? Normally it is with solid, liquid, and gas, but is there one with, say, liquid, gas, and plasma?

Posted: 10 Apr 2018 07:40 AM PDT

Why are there more venomous animal species in hotter environments than in cold?

Posted: 11 Apr 2018 06:01 AM PDT

If a website is able to grade your password as you’re typing it, doesn’t that mean that it’s getting stored in plain text at some point on the server?

Posted: 11 Apr 2018 05:16 AM PDT

What's to stop a Spectre type attack from getting your password at that time?

submitted by /u/Matraxia
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Do objects other than black holes emit Hawking radiation?

Posted: 11 Apr 2018 06:23 AM PDT

Why just black holes? Does it suddenly stop after it's not a black hole anymore? What happens then anyway?

submitted by /u/Fireheart318s_Reddit
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What is happening when we randomly lose slight hearing in one ear and hear a loud ringing sound in it for a few seconds before the ringing fades away?

Posted: 11 Apr 2018 04:24 AM PDT

Surgeons, how do you decide which scalpel blade to use?

Posted: 10 Apr 2018 11:57 AM PDT

Just curious--I'm a resident in internal medicine but I've only ever used 11 blades and 22 blades. (Plus I've never had to actually make a choice--whenever I've been in a situation where I needed a scalpel, one was handed to me and I went with it.)

submitted by /u/orihihc
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What's the deal with optimum fuel efficiency at 55 mph?

Posted: 11 Apr 2018 05:58 AM PDT

It's a commonly held belief that your vehicle is most fuel efficient at 55 miles per hour. To such an extent that in the fuel crisis of the 70s it was mandated that all highways have a mandatory speed limit of 55 miles per hour. Is it true that your vehicle is most efficient at 55 miles per hour? If it is true, what makes this number special; is it an Act of engineering? Or something about the physics around that speed that has something to do with wind resistance?

Thanks in advance.

submitted by /u/saward92
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Do scientists periodically recalculate the distance of the Earth from the sun, time of one complete rotation and time of one complete revolution?

Posted: 11 Apr 2018 03:16 AM PDT

Is it possible that the rotation and revolution of the Earth and distance to the Earth can change, resulting in a multitude of changes, particularly climate and our definitions of temporal measurements?

submitted by /u/truthserum23
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Do deaf people who sign have the same speech errors as voice talkers such as stuttering, words stuck on the "tip of their tounge," mashing two words together, etc?

Posted: 11 Apr 2018 04:21 AM PDT

Is the Flynn effect real, and if so, is it caused by epigenetics?

Posted: 11 Apr 2018 07:27 AM PDT

Why is restoring vision so much more difficult than restoring hearing?

Posted: 11 Apr 2018 07:16 AM PDT

What does Heisenberg's Uncertainty Principle mean for forces created by particles?

Posted: 11 Apr 2018 07:08 AM PDT

Let's say I cool down a proton as much as I can. Since I know it's momentum extremely well, I don't know it's position.

If I shoot an electron through the proton's possible positions, will it be attracted by the proton? Will it be attracted less? What happens if they bond?

submitted by /u/FreakinGeese
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Solitary confinement: from a neurosci or evolutionary perspective, what change does it cause and how much stimulation is needed to ward off the harm?

Posted: 11 Apr 2018 02:09 AM PDT

So there are no shortage of articles describing the behavioral changes brought on by SC.

But why are those changes brought about? From an evolutionary standpoint doesn't that stand out as a weird and glaring weakness? Wouldn't it be normal for us as a species to, at least intermittently, face medium to long periods of stimuli deprivation? That a being can be brought to madness from a simple lack of stimulation, seems strange doesn't it? You can easily refute that by saying "yes, but SC is actually quite elaborate, one has to be completely deprived to suffer the symptoms." But is that the case?

Example: is there a significant difference of effect between someone in SC with only a bed, a toilet, and a sink, versus someone with that plus an interesting book, a radio, or an interactive board game? In other words, just how much stimulation does a person need to avoid those negative affects? What if someone is dropped into a forest alone with nothing but a tent and food for a week and they can't wonder off because they don't know their location? Would they suffer the same symptoms?

Do we know specifically from neurological study where that line is between a dangerous lack of stimulation and just enough to remain sane?

submitted by /u/HD_Thoreau_aweigh
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What makes a given Surface, (i.e. the edge of a knife) 'sharp compared to another surface made of the same material?

Posted: 11 Apr 2018 02:05 AM PDT

I know that the answer revolves around force being exerted through a much smaller surface areal, in the case of a knife's blade, but I've never really cleared up, whether that's the entire story.

submitted by /u/molesen90
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If a galaxy cluster’s overall gravity overrides universal expansion allowing galaxies to collide, will a cluster eventually become one giant galaxy? If so, will all galaxies in the universe eventually merge into one?

Posted: 10 Apr 2018 07:04 PM PDT

Why does our tongue react different to something after eating certain things ?

Posted: 11 Apr 2018 05:30 AM PDT

For example, after eating chocolate, orange juice tastes more sour.

submitted by /u/RRiven
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Leakage of plasma due to vascular permeability in inflammation - only at venules?

Posted: 11 Apr 2018 05:18 AM PDT

I'm curious why the movement/leakage of plasma through the endothelium during acute inflammation only occurs at the post-capillary venules. Why can't leakage also occur at the capillaries, which are similarly porous?

One pathology textbook I've looked at states that the venules are the primary sight of plasma leakage, and a university web/infopage implies that the process occurs almost exclusively at the venules.

submitted by /u/qqq96
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What can the James Webb telescope see that the Hubble can’t?

Posted: 10 Apr 2018 02:43 PM PDT

Why do hangovers get so much worse you get older?

Posted: 11 Apr 2018 04:48 AM PDT