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Friday, April 28, 2017

Are there any poisons/toxins which, if taken separately, are fatal, but if taken simultaneously, are not?

Are there any poisons/toxins which, if taken separately, are fatal, but if taken simultaneously, are not?

Are there any poisons/toxins which, if taken separately, are fatal, but if taken simultaneously, are not?

Posted: 27 Apr 2017 06:31 PM PDT

What's reference point for the speed of light?

Posted: 28 Apr 2017 02:42 AM PDT

Is there such a thing? Furthermore, if we get two objects moving towards each other 60% speed of light can they exceed the speed of light relative to one another?

submitted by /u/IwishImadeSense
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Do x-rays have depth of field like regular cameras do? How do things look in an out of focus X-ray shot?

Posted: 27 Apr 2017 09:03 AM PDT

Do our brains process faces differently as we age?

Posted: 27 Apr 2017 02:39 PM PDT

For example, a five year old looks at a picture of the face of a ten year old and thinks they look old and mature, whereas if the child looks at that same picture ten years later, he'll probably think the ten year old looks childish. Can this be explained in the brain?

submitted by /u/JoeCool888
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How is linearity of quantum mechanics compatible with non-linear systems higher up?

Posted: 28 Apr 2017 06:20 AM PDT

One striking property of the Shrodinger's Equation is that it's linear - if I want to compute the evolution of a sum of waves, I can just compute for each wave and add the results up.

However, if you compose linear functions, aren't you always suposed to get linear functions? How can complicated systems (macro objects) exhibit non-linear behaviour if they are composed of linear parts? Especially confusing is the squared modulus rule for probabilities of measurement - where the hell does that come from? Squaring is pretty obviously nonlinear. How come?

submitted by /u/thetimujin
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Why does the tricuspid valve have 3 cusps and the mitral valve have 2 cusps? Why is there a difference?

Posted: 27 Apr 2017 05:52 PM PDT

When something exceeds its half-life, what does it become?

Posted: 28 Apr 2017 07:28 AM PDT

More directly, a muon has a half-life of 2.2 seconds. What happens after those 2.2 seconds? What does it become?

submitted by /u/Solmeaus
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What does the colour of gas giant planets, like Jupiter's Red Spot come from?

Posted: 27 Apr 2017 01:50 PM PDT

Why does Ice behind the ear mitigate a Vasovagal response?

Posted: 27 Apr 2017 06:08 PM PDT

There are many things that can trigger a Vasovagal response. One of the most common is having blood drawn. The affected may feel dizzy, nauseous, or may even faint. A lesser known treatment is to hold ice behind the ear (corresponding to the arm giving blood) for about a minute before and throughout the drawing of blood.

Physiologically, why does this help mitigate a Vasovagal response?

submitted by /u/thegreatroe
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Gravitons, Where do they come from? Are they a field like the Higgs Boson?

Posted: 27 Apr 2017 07:15 PM PDT

Hey guys, Im reading Steven Hawkins "The Universe in a Nutshell" and I'm confused on gravitons. I get photons being a release of energy as an electron moves down an orbit and I understand the particles that have to do with the weak nuclear force, I just don't understand the origin of gravitons. Are they emitted from interactions of particles or are they a field? Thanks!

submitted by /u/TheBoulder101
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Why does going from 20 or 30 frames per second to something like 60 cause an image to appear smoother (faster?), but going from 60 fps to 120 fps cause video to appear in slow motion?

Posted: 27 Apr 2017 01:35 PM PDT

Is it theoretically possible to reach space in a hot air balloon?

Posted: 27 Apr 2017 04:57 AM PDT

How do we determine an accurate half life of an isotope?

Posted: 27 Apr 2017 06:30 AM PDT

I have a general understanding of what half lives are and how we date things using them. My question is this -- how do we determine the actual rate of a half life for something beyond our immediate observable timeline?

For example, for potassium-40 the half life is considered to be about 1.3 billion years. Since we cannot directly observe that amount of time, how do we arrive that that is the correct half life? Is there a constant decay of the isotope that we can then project how long it would be for a half life? And if this is the case, how can we accurately factor in cases where exponential decay may occur?

Thanks for your time in answering my question. I apologize if this has been answered before and I was unable to find it -- still new to reddit.

submitted by /u/The_Nameless_Deity
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Are there any negative effects to long-term exposure to high-frequency/ultrasonic sounds like in animal repellent devices?

Posted: 27 Apr 2017 11:07 AM PDT

Looking for information related to mental and physical effects on children and young people specifically, but also in general.

The reason for this post is to find reputable sources that relate to the topic. Answers are fantastic, but appreciate citable resources as well.

submitted by /u/Cianistarle
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[Physics] How are electrons in an atom distributed?

Posted: 27 Apr 2017 04:59 AM PDT

So I'm fresh out of high school and what they taught us about the atomic model was niels bohrs model(I think) , with the definite locations of electrons arranged in shells around the nucleus. Thing is I recently stumbled across it online that this was extremely outdated and apparently what's now used is the electronic cloud model, can someone explain to me how this works? I tried reading about it but could only grasp about 50% of it. Some parts of it were just too complicated like, "an electron exists everywhere in the atomic at the same time" I can't seem to understand this part perfectly.

How do electrons in an atom exist? As waves or as particles? How are they spaced out, can they be pinpointed at a particular point?

submitted by /u/Temilitary
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Are there any examples of sexual reproduction that involves more than 2 gametes?

Posted: 27 Apr 2017 01:56 AM PDT

Excluding asexual reproduction, are there any examples that involve three or more gametes? If not why is there this limit throughout all taxa on earth?

Thanks!

submitted by /u/Qontinent
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Thursday, April 27, 2017

If an electric motor is supplied power but restricted in turning (like holding back a ceiling fan) what is happening which would cause it to 'burn up'?

If an electric motor is supplied power but restricted in turning (like holding back a ceiling fan) what is happening which would cause it to 'burn up'?

If an electric motor is supplied power but restricted in turning (like holding back a ceiling fan) what is happening which would cause it to 'burn up'?

Posted: 26 Apr 2017 10:31 PM PDT

If a redwood or pine tree were to live in the perfect conditions, with enough nutrients and without pests or disease or deforestation. Could the tree live forever?

Posted: 26 Apr 2017 09:41 PM PDT

Why is greenhouse gas one way?

Posted: 26 Apr 2017 07:48 PM PDT

So green house gas like CO2 supposedly keeps heat inside the atmosphere, but if it doesn't let heat back outside the atmosphere, why can heat get inside in the first place?

submitted by /u/scottymooney
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Why do things seem to start spinning the other way after reaching a certain speed?

Posted: 26 Apr 2017 07:45 PM PDT

If, instead of electromagnetic force, Magneto had control over the weak nuclear force, what would be the things he could do?

Posted: 26 Apr 2017 02:30 PM PDT

assuming he can control as well as he does magnetism(even though probably it does not correlate a 1 to 1 mach)

submitted by /u/joaosturza
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130000 year old mastadon in California. There aren't signs of meat removal on the bones. How do they know WHEN the tools were used to process the bones?

Posted: 26 Apr 2017 07:59 PM PDT

How feasible is it that 13000 years ago like current science believes whatever evolution of humans found the bones and processed them for the bone 117000 years ago? The tools can't be dated, right? They are stone and could have been in the area; there's reasonable doubt unless we can tell when a rock was broken to form it with dating and I am unaware? The lack of meat removal from the bones suggests the meat was unusable for whatever reason.

Or am I just waaay left field?

submitted by /u/aftersexhigh5s
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What sort of negative consequences could result from a desert ecosystem suddenly receiving an exorbitantly large increase in rainfall?

Posted: 26 Apr 2017 07:31 PM PDT

How do fins stabilize a rocket (or any other projectile)?

Posted: 26 Apr 2017 07:07 PM PDT

Why are severe allergic reactions to peanuts and other nuts so common compared to other foods and potential allergens?

Posted: 26 Apr 2017 03:04 PM PDT

Why do we take consider a zero point at r = infinity for Gravitational Potential Energy?

Posted: 26 Apr 2017 06:07 PM PDT

I have two questions, a main one (title) and a side question I added.

1) The first one has to do with the formula for deriving Gravitational Potential Energy. I learned that, for the derivation of Gravitational Potential Energy given large distances, we have to use the mathematical analytic way to derive an expression for it at a given distance.

To do so, you need integrate F dot dr from r to infinity. However, what I don't understand are as follows:

  • Why do we need to take the zero point at r = infinity? Why can't I take it from any arbitrary point to get a general expression for its GPE when I integrate?

  • Why is the work required to push an object to that height equal to the force due to gravity times the distance? Don't I need to apply a force that overcomes the force due to gravity to even raise it to begin with? Fg * h is definitely greater in magnitude than fg, but if I'm applying work to an object equal to Fg * h in the opposite direction of where it wants to move (towards the dominant object's COM) how do I know the magnitude of that work is sufficient to do so?

If I was trying to figure out how much energy I need to give an object to raise it from one point in space to another relative to, say the Earth, I could take the change in energy from the two points. If its energy at its initial point is 2 and the energy at the point I want it to be at is 8, I need to supply 6 joules to it. But how do I reconcile that with the derivation from the above paragraph?

2) The second question has to do with zero points for potential energy. Is this allowed because, as long as the distance from each object relative to another is the same no matter where I place a zero point, everything resolves? If at point A, object 1 is 2 units from point A and object 2 is 5 units from point A (all in, say, the x axis), then I'm not cheating by taking point B to be at object 1's position and saying object 2 is now 3 units from point B, right? Wouldn't its potential energy then change here though? That's okay because it's all relative, right? But the magnitude changes.. that's okay?

submitted by /u/sangstar
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Why are Magnetars extremely magnetic?

Posted: 26 Apr 2017 12:35 PM PDT

From my knowledge of magnetism, extreme heat would remove magnetic properties from substances by messing with the spin of electrons in orbit. So why are magnetars, which reach such extreme levels of heat, still so powerfully magnetic.

submitted by /u/SuperKalkorat
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Are men more likely to part with resources in the presence of attractive women?

Posted: 26 Apr 2017 01:27 PM PDT

I recall reading studies of this nature and I'm currently writing a piece on related issues. Any help appreciated.

submitted by /u/eradicati0nx
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Why does a ray of beta particles curve more than a ray of alpha particles in an electric field?

Posted: 26 Apr 2017 01:51 PM PDT

So I know the an alpha particle consists of 2 protons and 2 neutrons and that a beta particle consists of just one electron

How is it that a ray of beta particles will curve more in an electric field than a ray of alpha particles?

submitted by /u/DiamondxCrafting
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Why does boundary flow stay attached to an airfoil?

Posted: 26 Apr 2017 12:31 PM PDT

I'm a pilot studying to be a flight instructor, and I'm really trying to brush up on my aerodynamics. I have a background in the natural sciences, but never took physics, so a lot of it is kind of "learn as I go."

From what I've come to understand, the Coanda effect really doesn't apply because we're not dealing with a fluid jet.

The explanation I've heard is that the curvature of an airfoil creates a centripetal acceleration, which creates a pressure gradient where lower pressure exists closer to the airfoil.

But there's some relationship I'm missing, because to me that seems dependent on a tendency to stay attached to the surface. As I understand it, in order for there to be centripetal force acting on the fluid, some additional force must be acting on it to keep the boundary flow attached. Otherwise, when the air diverts over the top of the wing, it would just continue unaccelerated past the upper camber of the airfoil.

So what keeps the boundary flow "attached" to the airfoil? Is it something as simple as friction?

Any help to understand all of the various forces affecting curved boundary flows would be much appreciated!

submitted by /u/Longhornmaniac8
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Why do second and third gen stars contain heavier elements that the first gen stars?

Posted: 26 Apr 2017 05:02 PM PDT

Thanks

*than

submitted by /u/Litllerain123
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Could you be struck by lightning inside a storm cloud?

Posted: 26 Apr 2017 04:58 PM PDT

If I were somehow able to suspend myself inside a storm cloud, or stood on top of a blimp or some type or airship, would I be struck by lightning? Or would the lightning ignore me and go for the tallest object attached to the ground?

submitted by /u/FourSquareRedHead
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Why is it that early human remains are so rare to find in the Americas?

Posted: 26 Apr 2017 06:21 PM PDT

I just read through an article detailing the find of a mastodon skeleton that seems to show evidence of early human tool-making and use from ~130,000 years ago. In the article they mention that early human remains are notoriously difficult to find. Why is that?

Edit: original thread

submitted by /u/Clevercapybara
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Wednesday, April 26, 2017

The second law of thermodynamics seems to clash with the Stefan-Boltzman law in the following example. How can they be reconciled?

The second law of thermodynamics seems to clash with the Stefan-Boltzman law in the following example. How can they be reconciled?

The second law of thermodynamics seems to clash with the Stefan-Boltzman law in the following example. How can they be reconciled?

Posted: 26 Apr 2017 03:49 AM PDT

The second law of thermodynamics tells us that thermal energy spontaneously flows from a hot reservoir to a cold reservoir. Thus, it follows that no set of lenses and mirrors built around the sun can heat the earth to a hotter temperature than TSun.

On the other hand, the Stefan-Boltzmann law tells us that the power radiated from a back body is proportional to P~AT4.

Now imagine you could engulf sun-earth a system of two black bodies with radii R1 and R2, where R1<<R2 with a parabolic mirror, such that the sun and the earth are in the focal points of the parabola. Let us furthermore assume that the larger black body is held at a constant temperature T1. Then, all the power radiated by either body will be focused on the other. Thus it follows that

A1 T14 = A2 T24

Hence, since A1 < A2 it follows that T1 > T2.

But that violates the second law of thermodynamics.

Where did I go wrong?

submitted by /u/Concrete-Jungle
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A bluish aurora-like streak informally called "Steeve" has been recurrently spotted int the night sky of the Canadian prairies - what might it be, and how could this phenomenon be investigated?

Posted: 26 Apr 2017 05:46 AM PDT

What is the difference between the negative gravitational potential energy shared among two objects and the negative energy theoretically required to create an Alcubierre drive?

Posted: 26 Apr 2017 04:30 AM PDT

When moisturiser "sinks into" your skin, what actually happens?

Posted: 25 Apr 2017 06:01 AM PDT

Where does it go?

submitted by /u/skeletonclock
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What is the mean temperature of ITER as a whole when running?

Posted: 26 Apr 2017 02:36 AM PDT

I was wondering, given that the fusion reactor chamber contains hydrogen and stuff at millions of degrees, does this notably increase the temperature of the reactor as a whole? I mean, the reactor weighs about 5000 tons of steel, but it also has 0.5 gram hydrogen in its reaction chamber at 100,000,000 Kelvin, so I'm wondering what temperature would the whole reactor as a whole have.

submitted by /u/Laborbuch
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Did primitive human groups have 'leaders'? And if so how were the 'leaders' decided?

Posted: 25 Apr 2017 07:59 AM PDT

Edit: By primitive I mean pre-civilization, like Neanderthal time.

submitted by /u/NachoBait
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How does the nucleus in atoms stay together?

Posted: 25 Apr 2017 06:36 PM PDT

Basically that, how do all the protons stay together when their electromagnetic fields should make them repel each other ?

submitted by /u/Fyrember
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What makes something radiation-proof?

Posted: 25 Apr 2017 08:50 PM PDT

What causes something like lead to block radiation?

submitted by /u/Chukedog
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How does climate change cause the bleaching of the Great Barrier Reef?

Posted: 25 Apr 2017 05:58 PM PDT

I read an article recently claiming that, yet it didn't provide clear evidence or really explain how it does, may some one clarify for me please?

submitted by /u/cam3lwolfman
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I read somewhere that the AC travels on the surface of a conductor and the DC travels through the entire volume of the conductor. Why does this happen?

Posted: 25 Apr 2017 08:25 AM PDT

What are the general characteristics of different periods in Earth's geologic history (e.g., Permian)? What criteria are used to separate one period from another?

Posted: 25 Apr 2017 08:52 PM PDT

If two quantum particles are "entangled" and one is moved a great distance away, will it still react accordingly when its partner is subjected to a change?

Posted: 25 Apr 2017 06:37 PM PDT

I admit I'm not even sure the question makes sense (I never went further than earning my A in calculus-based physics), but here goes.

In the midst of an argument with an acquaintance about whether modern physics research supports various nebulous and semi-spiritual claims he was making about the connectedness of the universe, the power of the collective conscious to manifest things in reality, etc., he brought up the concept of quantum entanglement. He assured me that two quantum particles could become connected in such a way that even if one was subsequently moved a great distance away, the two would continue to influence one another in experimentally measurable ways. The example he gave was "like you could flip one's spin or something and the other particle would mirror that change from halfway across the world."

I told him laypeople like us often misunderstand the significance and real meaning of high-level research like he was describing and that I was SURE what he described is not how matter actually behaves. In fact, I told him if he could produce a reputable scholarly research article where that phenomenon had been observed, I would pay him $100.

He first tried to send me the Wikipedia page about quantum entanglement, and when I rejected that, he sent a link to this article that admittedly goes over my head.

So...do I owe him the money? If what he's claiming is true and changes to a particle in Chicago could influence the behavior of a particle in Paris, it will sort of revolutionize the way I see matter and our universe. I still won't accept the majority of his lofty claims, but this one would blow my mind. I'm totally willing to accept being wrong, but I am SO very much hoping that the more enlightened minds of the AskScience community will tell me that he is indeed misinterpreting this idea.

Thanks for any insight you are able to provide!

submitted by /u/hydrophile3
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Do cells of different body parts go through mitosis at different rates?

Posted: 25 Apr 2017 07:11 PM PDT

Maybe the best example I can think of is that I don't think it takes as long for a fingernail to grow 1 cm as it does a 1 cm wide wide to heal.

submitted by /u/yerekdoung
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How dp particles interact with the Higgs Field?

Posted: 26 Apr 2017 12:08 AM PDT

I am a 3rd year physics undergraduate doing research and a presentation on the ATLAS and CMS detectors at the LHC. I have done some reading on various CERN websites but I need some gaps filled in: I've taken introductory modern physics but have yet to take QM or EM courses.

So far I seem to understand that this non-zero field in a vacuum is similiar to the elecrromagmetic field, but instead is able to apply mass to fermions, bosons, etc. which interact with the field, but I'm not exactly sure why this happens? What process selects which particles have mass and which do not? I may have more questions to follow, but let's start with this.

P.S. I'm posting on mobile before I fall asleep at my desk, I apologize in advance for any grammatical / formatting errors.

Title edit: How *do particles interact with the Higgs Field?

submitted by /u/michouse
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What's happening in your brain when you experience deja vu?

Posted: 25 Apr 2017 10:55 AM PDT

How did Tyco Brahe account for movement of Earth in his measurements?

Posted: 25 Apr 2017 10:47 PM PDT

If Earth did not rotate, it would be comparitively simple to face the same direction every time for each measurement, and mark the position of an orbiting object.

But Earth rotates as well as orbits. How did Tyco account for all of this?

Also, how could he tell objects were moving in an elliptical orbit?

submitted by /u/yosimba2000
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How can Venus Flytraps close on their pray without a nervous system or muscles?

Posted: 25 Apr 2017 11:26 AM PDT

What is the effective actual brightness in relation to the human eye of planetary objects in the distant solar system? What I mean is: are photos of Saturn the brightness they are due to long exposures or would they actually be relatively dim objects due to their distance from the sun?

Posted: 25 Apr 2017 11:21 AM PDT

I just learned that the Aral Sea no longer exists and is now mostly a desert. Are there, and what are other comparable "recent" drastic changes of physical geography or biomes?

Posted: 25 Apr 2017 10:06 AM PDT

Link to wikipedia article here. I'm a bit surprised I didn't hear of this before, since it seems like a perfect example of human-caused climate change. I'm also aware that many dams will create sizeable lakes, but this seems like it would be much smaller than the disappearance of the Aral sea.

submitted by /u/ddxexex
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Does being in shape make you burn less calories during equivalent exercise?

Posted: 25 Apr 2017 12:09 PM PDT

This is an odd question, so bear with me. Assuming everything else was kept the same, would one person who was in shape burn the same amount of calories as someone who is out of shape? For example, if someone had the same bodily dimensions​ as someone else, and they both ran a mile, at the same exact pace, they would be putting in the same amount of WORK, but not necessarily the same amount of effort.

For example, someone who hasn't run in a while might have a more difficult time doing a 5k than someone who works out frequently, but do they necessarily burn more calories or not?

submitted by /u/Flobro4
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What is different between a piece of matter and a piece of antimatter?

Posted: 25 Apr 2017 10:52 AM PDT

What numbers and values change? And why is there not an anti-photon?

submitted by /u/PederPie
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Why don't professional athletes suffer from hearing damage due to constantly performing in extremely loud environments?

Posted: 25 Apr 2017 11:07 AM PDT

Pro sporting events are very well documented as being so loud that they cause hearing loss among fans. It seems to me that, above all, the greatest danger would be to the athletes themselves, since they are at the center of attention for every match. Although it might not pose a big problem for sports with less frequent matches, such as NFL players or professional boxers, how is it that players in the NBA or NFL, with 82 game seasons, don't suffer hearing damage?

submitted by /u/Asp184
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