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Thursday, March 21, 2019

Is there a reason that the majority of Earth's landmass is in the northern hemisphere?

Is there a reason that the majority of Earth's landmass is in the northern hemisphere?


Is there a reason that the majority of Earth's landmass is in the northern hemisphere?

Posted: 20 Mar 2019 03:44 PM PDT

What activates seeds to grow? Like, why can I leave a seed sitting on a table for years and it won't do anything but when I put it in dirt and water it, it starts to grow. How does it know, and was it doing?

Posted: 20 Mar 2019 04:45 PM PDT

Is there are maximum of brightness that light can reach?

Posted: 21 Mar 2019 05:59 AM PDT

I just read that brightness is defined by the amplitude of a lightwave and I just wondered if there is a maximum to that or what the highest brightness is humans achieved to create.

submitted by /u/Deeplorer
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If darker skin colors absorb more heat energy and have a higher resistance to cancer then why did humans who live in snowy/colder climates develop fare skin?

Posted: 21 Mar 2019 06:30 AM PDT

Does a brain physically change when it gets memories? Does a dead brain still possess the memories it had when it was alive?

Posted: 20 Mar 2019 07:32 PM PDT

How does mold on a bathroom counter get its food source?

Posted: 20 Mar 2019 08:53 PM PDT

One time I was at a public bathroom and noticed some mold growing under neath the tub that made up the sink, and it got me thinking. The mold probably isn't using the porcelain counter top as a source of food, but there's no obvious sign of organic material or glucose anywhere. And it is growing from a place where sunlight could not reach it.

How does it grow and sustain itself?

submitted by /u/woopertime
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In xray diffraction, why is it possible to use a fourier transform on a 2D image to get the 3D lattice information?

Posted: 21 Mar 2019 05:02 AM PDT

The key (and annoying) word here is "why". I have an idea, but I would like to hear your thoughts. Taken from a recent exam.

submitted by /u/porkchop-sandwiches
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Why do people's faces turn red when they're embarrassed?

Posted: 21 Mar 2019 06:32 AM PDT

Exactly as the title says. The body's natural reaction to embarrassment is to flush with blood and turn red. What mechanism or survival instinct causes this and why?

submitted by /u/TheStevest
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Korea has been divided for almost 75 years, how much have the people and language diverged and is this divergence the direct result of isolationism or natural drifting of two countries cultures?

Posted: 20 Mar 2019 12:08 PM PDT

How do high rise buildings filter outdoor air for circulation?

Posted: 21 Mar 2019 06:19 AM PDT

Not sure if this is the right sub for this question so feel free to delete.

I know for houses and apartments we use a small air filter, but how do large high rise buildings do it? Do they have large air filters that are the size of cars?

submitted by /u/jangooni
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How does the length of the primary solenoid inside the secondary solenoid affect the induced current?

Posted: 21 Mar 2019 07:17 AM PDT

We were doing some experiments with electromagnetic induction as we stumble upon this experiment,

The experiment went like this; each trial we take, we offset the primary solenoid by 10 mm, then we turned the power supply on and off for every trial, and measured the maximum current.

The data we gathered was quite inconsistent and we can't really determine a general behavior of the current from it. It would be a huge help to understand how it really the length of the primary coil inside would affect the current. Thanks!

submitted by /u/sirgaell
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Why is that the English question words “who,” “what,” “where,” “when,” and “why,” all begin with the letters “wh”? Is this a coincidence? Does it have anything to do with the questionesque nature of the word?

Posted: 20 Mar 2019 08:53 PM PDT

How does a virus, such as chickenpox or HSV, physically damage the skin to cause blisters?

Posted: 20 Mar 2019 04:27 PM PDT

What process occurs for a virus to cause wounds similar to small burns?

submitted by /u/VitriolicDiatribe
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I saw a double rainbow this afternoon next to each other one being more vibrant having red on its outer arch and violet as the inner. The other rainbow that was less distinct had the the colors in opposite order having violet on the outer circle. How did this happen?

Posted: 20 Mar 2019 08:41 PM PDT

How is it possible to measure the diameter of distant stars?

Posted: 20 Mar 2019 05:08 PM PDT

How do clinical risk estimators mathematically calculate the likelihood of an event?

Posted: 20 Mar 2019 10:59 PM PDT

There are a few tools that can be used in a clinical setting to asses if patients are at risk for certain events. One example of this is the ASCVD risk estimator, which will spit out an percentage prediction for how likely you will experience an adverse cardiac event.

I understand super basic epidemiology concepts that assess relative risk (x times more likely in this group), but this calculator seems to take in a lot of variables and spit out an exact percentage estimate rather than a relative one.

I've read through the resources this tool provides , from which I garnered which databases and studies the tool was derived from, but my question still remains, statistically, how do we create algorithms that can output risk estimation?

edit hyperlinks

submitted by /u/johoji
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Frequency dependent gain of a parabolic antenna/reflector, why?

Posted: 21 Mar 2019 05:41 AM PDT

I looked into parabolic reflectors and i am confused on why the gain changes with the wavelength. I checked "normal" antennas and apparently near field effects cause the effective arparture of an antenna to change with frequency. Which seems plausible.

But as far as i understand it a reflector should just reflect the waves that hit it (it's area) onto a feed antenna in the focus point of the reflector. Doesn't that mean the gain should only depend on the area of the reflector and not change with the wavelength?

My thinking is that the effective arparture of the feed antenna shouldn't matter if i focus the incoming wave directly onto the antenna using a reflector. Usually reflectors are explained using rays, my first guess is that that's the oversimplification that loses the frequency dependence? Or is the frequency dependence cause by the feed antenna?

submitted by /u/32BitLongSucks
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Why is earth warming faster at the poles compared to other latitudes from climate change?

Posted: 20 Mar 2019 07:34 PM PDT

Over the course of a year, how many calories have I used just growing hair?

Posted: 20 Mar 2019 07:26 PM PDT

That's just the calories my body used growing it, not the ones I used making all that hair presentable.

submitted by /u/anotherkeebler
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Why have no giant asteroids hit the earth in recent history?

Posted: 20 Mar 2019 07:15 PM PDT

What is the relationship between Quantum Field Theory and The Standard Model, are the two compatible?

Posted: 20 Mar 2019 04:14 PM PDT

If we can see cells with a microscope, why can't we just keep adding lenses/magnification to see atoms fairly clear (with electrons etc.) ?

Posted: 20 Mar 2019 09:36 PM PDT

If there is no oxygen in space, how do stars continue to burn without the basics for fire? Fuel, Oxygen, and Heat.

Posted: 20 Mar 2019 06:35 PM PDT

Where does vaginal flora in female come from?

Posted: 20 Mar 2019 03:23 PM PDT

I understand that our gut flora comes from what we ate and skin flora comes from the environment and all that. But where does the vaginal flora come from? If the lactobacillus need an acidic environment to live in, how do people 'caught' it? Why do most female have mainly lactobacillus in the vaginal while the other parts of our body is so diverse in regards with microbiota? And will anyone not have 'caught' lactobacillus but have other healthy bacteria residing in their vagina?

submitted by /u/ptly101
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Wednesday, March 20, 2019

Since batteries are essentially reduction-oxidation reactions, why do most batteries say not to charge them since this is just reversing the reaction? What is preventing you from charging them anyway?

Since batteries are essentially reduction-oxidation reactions, why do most batteries say not to charge them since this is just reversing the reaction? What is preventing you from charging them anyway?


Since batteries are essentially reduction-oxidation reactions, why do most batteries say not to charge them since this is just reversing the reaction? What is preventing you from charging them anyway?

Posted: 19 Mar 2019 10:25 PM PDT

What would happen if you smoked a cigarette on the ISS?

Posted: 19 Mar 2019 10:26 PM PDT

I just accidentally watched Event Horizon (1999) instead of the reputable science fiction movie Interstellar (2014) that I meant to. Half of the space crew in this movie are smoking. What would really happen if someone was to smoke a cigarette on the ISS? What if people chain smoked on the ISS as they do in Event Horizon (1999)?

Would these chemicals ever dissipate enough to avoid detection? or would they forever be detectable within the air supply and monitoring systems?

submitted by /u/RobBoblobula
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If you receive an organ transplant from a child, does the organ continue to grow until the organ would reach the child’s adult age?

Posted: 19 Mar 2019 09:07 PM PDT

If you were to spectate a person falling into a black hole, what would you see once they’ve passed the event horizon?

Posted: 19 Mar 2019 09:55 PM PDT

Why do we itch?

Posted: 19 Mar 2019 04:48 PM PDT

What's happening in our bodies when we get that really deep itch that we can't get? Is it a misfiring nerve? (I'm not asking about the itch you can get rid of by scratching - I mean when you scratch and scratch and there's no relief)

submitted by /u/RachelSays-
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How much of the deadliest toxin known to man, botulinum toxin, is present in Botox and how is it distributed uniformly in Botox in such small quantities?

Posted: 19 Mar 2019 10:37 PM PDT

Botulinum toxin has an LD50 of 1.3–2.1 ng/kg. Billionths of a gram are deadly. A fraction of the lethal dose is used in Botox; how can such a small amount of proteins be measured and distributed uniformly? Their exact process is proprietary so i'm not expecting a definitive answer, but I would like to know more about how such a small quantity can be reliably measured and handled, and how much of the potent toxin is likely present in Botox.

submitted by /u/So_What_If_I_Litter
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Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology

Posted: 20 Mar 2019 08:13 AM PDT

Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Biology, Chemistry, Neuroscience, Medicine, Psychology

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 does the number of passengers of a bus/train affect its speed?

Posted: 20 Mar 2019 04:21 AM PDT

Let's say the maximum speed of a empty bus is 100 km/h. Can it reach this speed when full of people? This sounds like a silly question but I need to know the answer

submitted by /u/lordzn
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If the neutron cannot be deflected by magnetic fields, how did scientists theorize its existence and how was it discovered?

Posted: 19 Mar 2019 09:14 PM PDT

Do we all have the same amount of blood?

Posted: 19 Mar 2019 09:38 PM PDT

Do people generally have the same amount of blood, or does it vary from person to person? For example, does a 400 lb man have more bold than a 130 lb man?

Can certain people lose more blood than others before passing out?

Are there people who can produce new blood faster than others?

At what age does our heart/circulatory system stop growing and produces a consistent amount of blood?

submitted by /u/FriscoBorn
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How does spicy food works in our mouth?

Posted: 19 Mar 2019 11:02 PM PDT

We all have experienced the hotness of chilli peppers and the ramen things. It is really hot and sometimes i realized that when we eat something really spicy, our mouth secrete a lot of saliva. Is it the saliva trying to cool down the temperature inside our mouth??and if that so, that means spicy food really "hot" right? In term of temperature? . Isn't it?

submitted by /u/Eddy_Danish
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When a plant triggers a distress signal, what does it accomplish?

Posted: 19 Mar 2019 09:24 PM PDT

This comes up because I found out that the fresh cut grass smell is a distress signal.

submitted by /u/professional_novice
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Is it possible to know a molecule's properties based on nothing but its chemical makeup?

Posted: 19 Mar 2019 08:51 PM PDT

Can a chemist look at the chemical makeup of a molecule and know, for instance, what state of matter it will be at room temperature, what other elements it will react with, what its half life will be, what color it is, or anything like that? Or does a molecule have to be synthesized to figure that stuff out?

submitted by /u/graaahh
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Why does angular velocity and angular momentum follow the 'right hand rule' for direction?

Posted: 19 Mar 2019 08:51 PM PDT

I've scoured youtube and did a cursory search here and on EI5 but i can't find a good explanation. Every youtube video i look up just says "yeah use the right hand rule to find direction!" (of L and w) without ever explaining WHY we use it. WHY does the direction of angular momentum, for example of a "spinning ice skater" (classic example) who is spinning clockwise when viewed from above, point DOWN? Nothing is actually going down! (is it?!)

I watched one video and some guy said it's just a convention we decided on. But then i watched professor Lewin's demonstrations and it can't just be a convention because the objects actually follow these rules in the real world. Did we just decide to use this convention so it matches observation?

Can anyone explain why ang. momentum and ang. velocity vectors have these odd directions?

submitted by /u/sonofpicard
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Why are there no non-composite images of the Earth?

Posted: 19 Mar 2019 07:45 PM PDT

My flat earther father would like to know this. Thanks.

submitted by /u/FatalTalon
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Have there been any large scale physics experiments (e.g. LIGO, LHC) that ended up a failure due to an inaccurate predictive model?

Posted: 19 Mar 2019 07:57 PM PDT

A lot of time, development, and money go into devices aimed at bettering our understanding of the universe. I frequently hear of the findings enabled by various particle accelerators or other particle detectors.

But has there ever been a large-scale investment made in a system whose very underlying theory proved faulty? I suppose this could apply to space probes and science satellites as well.

submitted by /u/Phormicidae
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How does helium actually increase the pitch of your voice?

Posted: 19 Mar 2019 11:51 AM PDT

If the planets (including the sun) orbited around the earth, what differences would it make?

Posted: 19 Mar 2019 02:03 PM PDT

I remember learning in history that at some point people believed that the planets orbited the earth rather then the sun, later on in my science class we were talking about something similar when I asked my science teacher a question, "What differences would be seen in a hypothetical system where the planets orbited around the earth rather then the sun?" I didn't get an answer. I have had this question bounce around my head for a while now and recently discovered this subreddit. So here I am, doing the thing, in hopes of getting an answer.

submitted by /u/GLasStringed
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Why does baryonic matter curve SpaceTime?

Posted: 19 Mar 2019 12:48 PM PDT

Why does common matter/energy curve SpaceTime? I've seen in countless shows the heavy ball in the middle of a rubber sheet. But that doesn't explain why matter and energy actually curve SpaceTime. Can someone explain this in layman's terms?

submitted by /u/Mrglock426
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What are spider webs made of? How much can a spider web, and how does it regenerate it?

Posted: 19 Mar 2019 12:35 PM PDT

Why is Saturn full of Helium 3 but very rare on Earth? And what makes it such a great source of energy?

Posted: 19 Mar 2019 05:30 AM PDT

Tuesday, March 19, 2019

Is it possible for animals to be allergic to humans?

Is it possible for animals to be allergic to humans?


Is it possible for animals to be allergic to humans?

Posted: 19 Mar 2019 03:08 AM PDT

Humans can be allergic to dogs, cats, etc. Is it possible for animals to be allergic to us?

submitted by /u/hsym
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If a body rejects an organ transplant, can that organ be used for someone else, or is it no longer usable?

Posted: 18 Mar 2019 07:54 AM PDT

If my body rejects a kidney, can it be used for the next applicable person on this list, or is it toast?

submitted by /u/Theonlykd
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What do tiny spiders eat?

Posted: 18 Mar 2019 05:13 PM PDT

I've got a tiny spider, not more than 1-2cm across, living in the frame of my shower door. My wife hates cobwebs, so removes its newly spun web every few days, but the little fella always spins another. I can never see anything on the web, and I doubt it could hold a fly, even if one flew into it. But Incy is still there, spinning away. So what is it eating and how is it catching it, if not on the web?

submitted by /u/gjs78
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How exactly does nothing (or almost nothing) react with glassware?

Posted: 18 Mar 2019 08:42 PM PDT

I've been watching CodysLab and HTME on YouTube and seeing them put all those incredible reactive and dangerous into glass started wondering why/how it works? Are there other things that are as resistive to chemicals as glass is?

submitted by /u/torohangupta
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How do statins work to reduce blood cholesterol?

Posted: 19 Mar 2019 03:14 AM PDT

If you were standing on the moon's surface, would you be able to see the horizon curve?

Posted: 18 Mar 2019 08:52 AM PDT

If not, how small would a planet/moon have to be to be able to notice a curve of the horizon?

submitted by /u/adarco23
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How long does it take sedimentary rock to form?

Posted: 19 Mar 2019 03:19 AM PDT

For example, let say a depression was flooded with silt, clay, sand and the like. After this flood it remained arid and dry. How long would it take to turn into rock?

submitted by /u/dredawg1
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If you wanted to push an orbital object towards it’s gravitational well, *as fast as possible*, (say, like, using rockets to push Europa into Jupiter...) would you slow the object’s orbital speed (x)? Or push the object directly towards the gravitational center, at equal force (y)?

Posted: 18 Mar 2019 05:50 PM PDT

Would that depend only upon relative speed vs mass? Or is there a line between l speed/mass v constant(0 Speed)/mass to determine the best direction? Never really got into this class in college. But I wanna know now..

submitted by /u/Wickedpissahbub
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Why do hot things typically turn red?

Posted: 18 Mar 2019 02:09 PM PDT

What is the Adam's apple and what is its function?

Posted: 18 Mar 2019 11:47 AM PDT

What is happening in our lips/mouth that causes spicy foods we eat to feel hot or "spicy"?

Posted: 18 Mar 2019 03:06 PM PDT

Can a micro burst rains occur at high elevations? IE high mountain territory ~5000 feet

Posted: 19 Mar 2019 03:01 AM PDT

I know they happen in the desert sometimes, could they happen in a place like Denver or Flagstaff?.

submitted by /u/branflakes4547
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Does atmospheric pressure change over geologic time, or has the barometer always been about 1 atmosphere?

Posted: 18 Mar 2019 06:05 PM PDT

Does atmospheric pressure change over geologic time, or has it always been about 1 atm? We have so much evidence for wildly different climates, sea levels, gas concentrations, to the point where humans couldn't have survived at points in Earth's history. But is there a geologic barometer we can check?

submitted by /u/Simplethrowaway4828
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If someone is having a nightmare will his/her heart rate increase or be the same?

Posted: 18 Mar 2019 08:16 AM PDT

Could Earth’s Climate Become Like Venus’?

Posted: 18 Mar 2019 12:47 PM PDT

There's a lot of talk about Climate Change here on Earth and often I hear that the worst case scenario is for Earth to become like Venus. 471C and runaway Climate Change.

1) But, is it even physically possible for Earth to become like Venus with our carbon sinks in the Oceans/plate tectonics, magnetosphere, relatively fast rotation on our axis?

2) If 1 is true, how likely is it that climate change here on Earth could push us to runaway climate change where Earth becomes like Venus?


-None of this is to dampen the severity of the rate of climate change.

-Please try to link academic sources if you can

submitted by /u/urunclejack
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How Does the Extra Food Mass Exit the Body of an Exerciser?

Posted: 18 Mar 2019 03:59 PM PDT

Two people consume the exact same diet. One exercises and does not gain weight. The other sits and does gain weight.

Which bodily excretion accounts for the extra loss of mass from the active person? Sweat, exhalation, urine, feces, or other?

submitted by /u/wingalls13
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How do websites like google give you search results?

Posted: 18 Mar 2019 07:44 PM PDT

Do they scan the whole internet?

submitted by /u/hzeme1
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Would a Pangean year be longer than 365 days?

Posted: 18 Mar 2019 06:22 PM PDT

Or is the distance from the sun the determining factor of a day? I was going to ask this on r/nostupidquestions , but I couldn't find anything on it during a google search, so I thought you all may know.

submitted by /u/Sentient_Sloth2
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Why are microwaves effective at heating food but not plates?

Posted: 18 Mar 2019 09:13 AM PDT

What makes vegetables edible when compared to simple grass and bushes?

Posted: 18 Mar 2019 06:52 AM PDT