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Monday, October 30, 2017

What makes a food 'filling'? Is it just calories?

What makes a food 'filling'? Is it just calories?


What makes a food 'filling'? Is it just calories?

Posted: 29 Oct 2017 06:48 PM PDT

Does the universe have a center of mass?

Posted: 29 Oct 2017 04:25 PM PDT

Are there things in genetics that can skew the general 50/50 nature of having a boy or girl?

Posted: 30 Oct 2017 06:13 AM PDT

We have a running joke in our family that "we only make boys".

My father was one of 8 brothers. he himself had 3 sons (2 different marriages) his middle son has 2 sons (again 2 different partners) and is expecting a 3rd son in the next few months. nobody else in our family has kids yet.... now based on the fact we are taught all the way through schools that the boy girl chance is about 50/50, that makes the chance of my family's male child run of 14 children in the region of 1/16400... i.e pretty unlikely

Obviously we could just be incredibly Lucky/Unlucky (delete as appropriate) but i'm curious to know if there is anything that makes people more predisposed to creating male or female offspring?

submitted by /u/devlifedotnet
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Do you have to take into account atmospheric pressure when calculating the upward acceleration of rockets?

Posted: 30 Oct 2017 04:45 AM PDT

Hi, If yes, do you have to apply the force of gravity and the force of atmospheric pressure separately?

submitted by /u/Szesan
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Is there a way to know where did the asteroid A/2017 U1 came from?

Posted: 30 Oct 2017 05:45 AM PDT

The trajectory of the asteroid A/2017 U1 has been already calculated/estimated from observations, so we know now which direction it came from, I think I have read somewhere that it came approximately from the direction of Vega. However its approximation speed to the solar system (26 km/s) means it would have taken 300,000 years to make the travel, what may locate Vega and all near stars from a totally different positions, not to mention further stars.

submitted by /u/jambreunion
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If the windchill is below freezing but the actual temperature is above freezing, will water freeze?

Posted: 30 Oct 2017 03:20 AM PDT

Why is it that oil has a very noticeable change in viscosity at different temperatures, but water does not?

Posted: 29 Oct 2017 08:17 PM PDT

Is it possible for two suns to exist in a solar system?

Posted: 30 Oct 2017 05:01 AM PDT

Is it possible to have two suns, next to eachother, with planets rotating around them, as one solar system? How would that work, and how would it affect the planets?

submitted by /u/elosociu
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How did we figure out the mass of elementary particles?

Posted: 29 Oct 2017 02:56 PM PDT

Have always we figured out the mass of such small particles.

submitted by /u/SyntheticPanthera
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What is difference between Photon in terms of quantum of light and Electromagnetic force carrier?

Posted: 30 Oct 2017 07:10 AM PDT

It says it all, i don't seem to find an answer, if photon is referred to both what is different?

submitted by /u/SoDifferentDude
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Don't plasma drifts due to curvature and gravity mean that tokamaks are inherently flawed?

Posted: 30 Oct 2017 01:00 AM PDT

It's what it sounds like.

Charged particles traveling in a curved path have a curvature drift, which results in the particle having...

... a slow drift which is perpendicular to both the local direction of the magnetic field and the direction to the local centre of curvature of the field.

i.e. up or down.

Along with the myriad other drifts that charged particles undergo, one is due to an external force - in this case, drift due to gravity. This could cause a drift in a couple different directions, depending on which magnetic field you look at.

Tokamaks will have both of these drifts present, and both drifts serve to drive charged particles into the wall of the reactor, which immediately causes them to lose any potential of fusion. Therefor, tokamaks are doomed to fail before they ever get the chance. Hence, Stellarator.

This is stuff I learned in an introductory plasma physics course. If it's such basic knowledge, and seemingly inescapable for toroidal approaches to fusion, why are world-class physicists still chasing tokamaks, like ITER? Is there a secret that I just don't know about?

submitted by /u/rockitman12
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Why do cosmic X-ray sources appear to be more isotropic than the microwave background radiation?

Posted: 29 Oct 2017 04:09 PM PDT

This image is composed of two distinct pictures of the Milky Way: the left one on X-ray wavelengths, the right one on the microwaves. Shouldn't X-ray sources appear more localized, at least compared to the CMB radiation map?

submitted by /u/TheGreatDaiamid
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How are the leaves of touch sensitive plants, i.e. Venus fly traps and the shame plant actuated? How do they sense that there is something on them without nerves?

Posted: 29 Oct 2017 05:56 PM PDT

how can condensation occur INSIDE a sealed plastic bag?

Posted: 30 Oct 2017 05:38 AM PDT

So i have a sealed bag of jelly (each with their own individual plastic packaging). I placed this in a cooler box with ice. And when i took it out, there was water INSIDE the plastic packaging. I don't understand where this water came from (no holes in the plastic bag).

I think it's condensation but does that not require humid air. Temperature that day was pretty hot so there is humid air AROUND the plastic packaging, but would the air inside the packaging itself (why would that be humid) be able to cause condensation from the jelly?

submitted by /u/hapyapolsors
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What kind of effect would the gravitational waves generated by GW170817 have on surrounding star systems (aside from the massive release of electromagnetic energy)?

Posted: 30 Oct 2017 01:24 AM PDT

Is "a coma" a blanket term for multiple conditions?

Posted: 29 Oct 2017 04:10 PM PDT

Why is it possible for photons to have exactly the right frequency to cause an electron transition in atoms?

Posted: 29 Oct 2017 10:58 AM PDT

As far as I understand the energy levels of electron orbitals in atoms are strictly quantised. So it takes x amount of energy for an electron to move from n=1, to n=2.

So to make this transition the atom can absorb a photon of energy E=x=hf.

The possible energy spectrum of photons is continuous (?), so to me it seems like the probability of any photon having an energy of exactly x should be zero.

Given this, the probability of a photon being able to cause a transition should also be zero.

What part of my reasoning is wrong?

submitted by /u/PencilRiddenYarn
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Are we sure that SI units are sufficient?

Posted: 30 Oct 2017 02:58 AM PDT

For example, in the past, people can know and measure quantities like time, mass, length. And it was sufficient, but they didnt know about electricity or didnt know how to measure temperature. Today we know. But is it possible in the future we will have to "invent" new quantity/ies because SI units wont be sufficient? Some quantities we even dont consider today?

submitted by /u/sadam23
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How can I separate gold mixed with iron ?

Posted: 30 Oct 2017 06:22 AM PDT

I think title says it and also sorry for bad english

submitted by /u/blackman9977
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How do we know anyons exist if they only occur in two dimensional systems?

Posted: 30 Oct 2017 02:32 AM PDT

How would we ever be able to prove that anyons exist? Is it possible to create our own two dimensional system?

submitted by /u/ringbear9000
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If you have a dimmable lightbulb and always turned it to partial brightness, would it last longer than a lightbulb always turned to full brightness?

Posted: 29 Oct 2017 10:23 AM PDT

Dark matter has mass and is effected by gravity. Does this mean that dark matter coalesces into planet and star-like masses?

Posted: 29 Oct 2017 10:35 AM PDT

If that is the case it blows my mind that there is matter like this in the universe and we have no way of directly observing it. Would a normal matter object fall straight through a planet-like mass made of dark matter?

submitted by /u/yoshi8710
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Sunday, October 29, 2017

[chemistry] Why does Cl- not form Cl2 in water?

[chemistry] Why does Cl- not form Cl2 in water?


[chemistry] Why does Cl- not form Cl2 in water?

Posted: 29 Oct 2017 06:15 AM PDT

I work in water treatment but I'm not a chemist. I'm seriously considering further education because the more I learn the more I want to know.

I use drop-test kits and a typical water sample can contain 30ppm Cl- (chloride) , 0.3ppm ClO- (free chlorine) and 0.4ppm Cl2 (total chlorine)

What stops the Cl- from becoming Cl2?

Why does my total chlorine test kit not pick up the chloride?

What would have to change in order to make the Cl- form covalent bonds and become Cl2?

What are some good sources of information on water chemistry?

submitted by /u/Ken-_-Adams
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Why are all electrons the same mass, as well as protons and neutrons?

Posted: 29 Oct 2017 06:46 AM PDT

I've been wondering this for awhile now and haven't quite found an explanation for it, how is it that all of these particles are universally the same no matter where you measure it?

submitted by /u/pjcandleanaiii
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3 Earthquakes near the north pole today, is there a fault that extends through that area? Why would a 5.7, 5.7 & 6.0 all occur in the same location?

Posted: 28 Oct 2017 10:13 PM PDT

5.7 North of Franz Josef Land 2017-10-28 16:13:54 (UTC) 10.0km 5.7 North of Franz Josef Land 2017-10-28 16:16:07 (UTC) 10.0km 6.0 North of Franz Josef Land 2017-10-28 19:11:01 (UTC) 10.0km

submitted by /u/MasterOfNotAThing
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What is the farthest direct parallax measurement of an object?

Posted: 29 Oct 2017 03:17 AM PDT

I haven't been able to find any clear reporting on the Gaia mission, even though it was supposed to be able to directly measure a lot farther than before.

submitted by /u/AStatesRightToWhat
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Do cosmic rays have any effect on modern computing software/hardware?

Posted: 29 Oct 2017 12:13 AM PDT

I've been learning about how many hardware components rely on precise quantum mechanical interactions to work properly, and just wondered if extra solar EM waves have any measurable impact on modern hardware/software technology? I would imagine if a high energy gamma ray were to somehow find its way into a computer, it could cause some mayhem, but didn't know if it was a documented phenomenon. Thanks in advance!

submitted by /u/throwaway3141598
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How are we able to flex each digit of the hand individually when the flexor digitorum is one muscle that has attachments to the 4 digits?

Posted: 28 Oct 2017 08:14 AM PDT

Can we hope to either stumble upon an organism that feeds of radiation or create one?

Posted: 28 Oct 2017 09:13 AM PDT

I was reading a comic book earlier today called 'Low'(really good read) and near the end as humans set foot on earths surface (they had gone into the depths after catastrophic radioactive warfare) for the first time in thousands of years they encounter and entirely different ecosystem. An ecosystem that has evolved not just to feed off radiation but to use it in self-defense. I've read the concept before but I never really thought of it in terms of feasibility.

submitted by /u/Vic_KE
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Is it possible to prove the existance of the inflaton field by detecting an "inflaton particle"?

Posted: 29 Oct 2017 05:57 AM PDT

I've heard that the inflaton is supposed to be a scalar field, just like the higgs field; so I was wondering, would it be possible to prove it's existence by detecting an "inflaton particle"? Does such a particle even exist?

submitted by /u/iron14
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When you get cancer, is most of the pain focused on the area that you have cancer in? Or does the pain spread out across the body regardless of the origin of cancer?

Posted: 28 Oct 2017 05:36 PM PDT

I understand that the pain is, in general, throughout the body. However, is it "more" painful in the specific area that the cancer originated? For example, would colon cancer have more pain in the colon area than the rest of the body?

submitted by /u/theroyalham
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Why does turning a PC off then on again often fix the problem?

Posted: 29 Oct 2017 03:17 AM PDT

Why are Venus and Uranus the only planets in the solar system that rotate clockwise?

Posted: 28 Oct 2017 12:18 PM PDT

In terms of the mechanism of action of aspartame, why is it 200x sweeter than sugar?

Posted: 28 Oct 2017 09:17 AM PDT

What is the smallest amount of blood that can be analyzed in a medical blood lab?

Posted: 28 Oct 2017 05:45 PM PDT

Follow up question: Is a small portable version of a a blood lab possible ?

submitted by /u/Communistbourgeois
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What type of software would be needed to simulate an asteroid impact, and the resulting weather and climate impact because of the modeled impact?

Posted: 29 Oct 2017 03:28 AM PDT

My knowledge of this is very layman's level. I'm writing a screenplay on this and I want to be as on point as I can.

The most I've been able to find from google is Impact Earth, Crater Impact, and not much more than these types.

But I want to be able to be much more specific, like what temperature the area my characters who are a few hundred to a few thousand miles away are going to be experiencing. What type of timeframe would it be? Will it be -90 or just below freezing, or would that part of the earth even freeze and it be nbd? How long would it take, and how long would it last for the different locations that the characters will be? those types of questions are beyond my abilities to answer.

submitted by /u/rreighe2
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Why can your brain simulate sensory sensations during a dream but not while awake and day dreaming?

Posted: 28 Oct 2017 09:04 AM PDT

For example, a kissing sensation feels real while asleep and dreaming but not daydreaming.

submitted by /u/Piddling
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Are any other animals able to interpret differences in human facial expression?

Posted: 28 Oct 2017 05:45 PM PDT

For example, are there any predators that would understand a human snarling with teeth bared, similar to what many other animals do?

submitted by /u/15MinuteUpload
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Does earth's center of gravity shift as the topography changes (mountains, tides)? Does the core move?

Posted: 28 Oct 2017 02:54 PM PDT

Is there a science behind Origami, or do different shapes get discovered simply by trial and error?

Posted: 28 Oct 2017 08:05 AM PDT

Can an opening in an electromagnetic wave reflector that is smaller than the wave, pass it through?

Posted: 29 Oct 2017 12:20 AM PDT

We did an experiment in class where we covered our phones in tin foil and tried to call each other. And our teacher said that we have to make sure there are no holes in the foil. But how can a really tiny hole pass let through a wave thats up to a meter long?

submitted by /u/fucmylife
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Why do Domesticated Cats like to run in front of your legs when you're walking? What behavior is this demonstrating?

Posted: 28 Oct 2017 08:31 AM PDT

I honestly don't know the answer to this - you'd think the negative feedback of being kicked (accidentally) everyday would eliminate the behavior.

submitted by /u/DrBearcut
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How do we know what is in the center of the Earth?

Posted: 28 Oct 2017 12:26 PM PDT

According to Google, the deepest anyone has ever gone is about ~7 miles below Earth's surface (James Cameron, Challenger Deep submarine)... Earth is 7917 miles in diameter... so the FARTHEST down we have observed, ever, is like 0.194% of the RADIUS of Earth, right? So the other 99+% is not observable by any current means. How do we know what is beneath us, especially at the center? I know we have a magnetosphere that protects us from harmful particles, so that is a clue. What else leads us to "know" anything about the center and mantle? Seems like it would have to be speculation/theory

Edit- math was off on the radius percentage... I think that's right now? 0.194?

submitted by /u/JOHANSENATOR
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Saturday, October 28, 2017

Can there be an orbit around a black hole in which the apoapsis is above the photon sphere, but the periapsis is below the event horizon?

Can there be an orbit around a black hole in which the apoapsis is above the photon sphere, but the periapsis is below the event horizon?


Can there be an orbit around a black hole in which the apoapsis is above the photon sphere, but the periapsis is below the event horizon?

Posted: 27 Oct 2017 09:16 AM PDT

Is the Unit Circle and the Complex Plane related at all?

Posted: 28 Oct 2017 06:55 AM PDT

When learning trigonometry, the idea of the unit circle was the main mechanism to describe the effects of angles and the sine and cosine functions. Now that I'm learning about Q.M. and Euler's formula, etc, it's pretty evident that the imaginary plane and trigonometric functions are intertwined. How did these two sort of distinct ways to look at trigonometric functions (I.e the unit circle vs complex plane) come to be? Did one come from the other, or are they related? Is there a reason euler's formula and complex relations baren't taught in tandem with trigonometry? Thanks in advance!

submitted by /u/throwaway3141598
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What causes viruses to take different structures? As an example Ebola is a string like structure, where as the flu is spherical.

Posted: 27 Oct 2017 06:34 PM PDT

And does the structure change the effects, like symptoms, transmission,etc.

submitted by /u/z00b_
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Would it be possible to create a cutter out of air by funneling huge amounts of wind through a tiny opening?

Posted: 27 Oct 2017 05:50 PM PDT

If the planet was shaped like a donut, how would gravity work in the middle?

Posted: 28 Oct 2017 06:12 AM PDT

Why do we have two sets of teeth in our lifetime?

Posted: 27 Oct 2017 03:53 PM PDT

How exactly were the first forged iron tools/weapons made without iron tools like hammers, anvils, tongs, etc.?

Posted: 27 Oct 2017 08:07 PM PDT

This question is inspired by the recent primitive technology video showing the building of a natural draft furnace:

https://www.youtube.com/watch?v=u7wAJTGl2gc

It got me thinking on a quandary:

you need iron tools to make iron tools (and by this I mean, you need a very good and strong iron hammer to hammer away impurities in molten/hot iron and to shape it you need tongs and an anvil to hammer against.

so how did the first people to break this chicken and egg problem do it? Did they use stone tools?

thanks!

submitted by /u/lingben
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Did scientists in the 19th century really think that the sun and other stars reflected light from another source?

Posted: 28 Oct 2017 06:53 AM PDT

In Thomas Dick's Celestial Scenery (1838 - 1848 editions) he states in the introduction, referring to stars:

Do they shine with borrowed light, or with their own native lustre?

and later in his 1869 edition of The Christian Philosopher he says

The immense distance at which the nearest stars are known to be pplaced proves that they are bodies of a prodigious size, not inferior to our own sun, and that they shine not by reflected rays, but by their own native light.

suggesting that at some point between 1848 and 1869 the idea that the sun and other stars might be reflecting light was shown to be incorrect.

Was this something that scientists in the 1800's thought might be how the sun generated its light or was this an aberration of christian scientists like T. Dick?

submitted by /u/hasbrochem
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If the universe is constantly expanding, then are we and all the other planets also expanding?

Posted: 27 Oct 2017 05:21 PM PDT

Similar to putting a drawing on a balloon and blowing it up in size?

submitted by /u/keptsecret1
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Recent advances in Navier-Stokes equations?

Posted: 27 Oct 2017 04:20 PM PDT

Hi all,

I'm just wondering if anyone knew of any current research that's looking into exact solutions to the full Navier-Stokes equations?

Also, has any progress been made on solving the full NS equations at all? I know about reducing them to something solvable by considering the Reynolds number, but apart from numerically, it's my understanding that we haven't solved them yet.

submitted by /u/KieranMontgomery
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Would it be possible to make elements such as iron and copper in particle accelerators/colliders?

Posted: 27 Oct 2017 06:47 PM PDT

And how much of these elements would you be able to create?

submitted by /u/BHjr132
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Why is it that you cannot feel the inside of your body, yet when you drink a hot or cold drink you can feel it rush through you?

Posted: 27 Oct 2017 06:18 PM PDT

Why do we laugh when we get tickled?

Posted: 27 Oct 2017 04:28 PM PDT

Why does leaving Earth require an "escape velocity" rather than an "escape force"? What happens that requires the rocket to be moving at a certain speed for a successful launch?

Posted: 28 Oct 2017 12:48 AM PDT

Can nuclear power still be achievable without uranium?

Posted: 27 Oct 2017 02:10 PM PDT

I'm sorry if this is a bad question but I've recently been looking into nuclear power energy and it seems very efficient but the problem is that uranium isn't the safest element of them all. From what I've read, the reason uranium is used is that it's the easiest element to undergo nuclear fission (the splitting of atoms). My question is can we use another element that, like uranium is easy to undergo nuclear fission but unlike uranium is fairly safe (meaning a potential nuclear meltdown that won't spread radiation)? If so, why haven't we tried it?

submitted by /u/Execute-Order-66
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Travel Between Earth and Sun-Earth Lagrange Points 4 and 5: energy requirements?

Posted: 27 Oct 2017 11:28 PM PDT

From Wikipedia: Earth trojan

The orbits of any Earth trojans could make them less energetically costly to reach than the Moon, even though they will be hundreds of times more distant.

Can somebody confirm for me whether or not this line from Wikipedia is correct? Also, what would be the most energy-efficient way for a spacecraft to travel from Earth to either of those two locations?

If I remember correctly, there have been some spacecraft sent on heliocentric orbits, but I am not sure if any have gone specifically to Sun-Earth L4/L5.

submitted by /u/DDRussian
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Are reptilian brains significantly different to mammals'? Can reptilians learn, or feel emotions?

Posted: 27 Oct 2017 05:14 PM PDT

Why can some animals, like snakes, eat only once and not need to again for months whilst animals like humans need to feed multiple times a day?

Posted: 27 Oct 2017 01:14 PM PDT

We say that the Universe is expanding. But what would be the difference in saying that we are actually compressing? Wouldn't that explain a lot of things that expansion does not?

Posted: 27 Oct 2017 09:03 PM PDT

I mean, it's a question of relation, isn't it? To me as a layman who loves space and science, it is obvious that somehow, in ways I do not understand or pretend to be able to express, whatever "we" are, fell into a black hole, and that the thing we are experiencing as expansion is in fact our polar perception of things shrinking as we close in on the event horizon.

Wouldn't this explain, well, everything? It would explain heat death pretty neatly, wouldn't it?

submitted by /u/tjackpundarn
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Why don't you sneeze while sleeping?

Posted: 27 Oct 2017 01:30 PM PDT

Are sound waves affected by friction?

Posted: 27 Oct 2017 10:12 AM PDT

Will a sound that is amplified over a smooth frictionless surface travel further than the same sound traveling over a "rough" surface?

submitted by /u/The-Jolly-Roger
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When a woman is pregnant, does the baby have a sense of direction? (For example, does the baby feel if the mother were to be lying down sideways as opposed to standing up straight)

Posted: 27 Oct 2017 06:08 AM PDT

I was having a conversation last night with my wife (who is 4 and half months pregnant) about baby movements in the stomach. I know that the baby can feel some of her movements and can definitely tell when she's moving around or not. But I was wondering if the baby can feel any sense of direction in the womb (if my wife was upside down vs. standing up straight, would the baby notice a difference?)

submitted by /u/nayan742
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