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Monday, September 4, 2017

Is a single Elephant's skin cell bigger than a human's skin cell?

Is a single Elephant's skin cell bigger than a human's skin cell?


Is a single Elephant's skin cell bigger than a human's skin cell?

Posted: 03 Sep 2017 01:15 PM PDT

People built a "Z machine" on Earth that creates a temperature of 2 Billion Kelvin. How can this temperature be generated and why does this temperature not melt the entire facility that creates it?

Posted: 04 Sep 2017 02:37 AM PDT

For scale, this is approximately 100x hotter than the center of the sun.

Given that the sun only has an outside temperature of 5,500K and easily heats up Earth to 300K+ over a distance of 150 million kilometers, shouldn't a temperature of 2,000,000,000K on Earth itself cause severe damage of some kind?

submitted by /u/Linnun
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How soon after an organism 'dies' are all of its cells dead? its bacteria?

Posted: 03 Sep 2017 10:12 PM PDT

Let's say an organism dies instantaneously (no previous oxygen deprivation). How long would the cells continue to be alive despite the macro organism being considered dead? How long would the bacteria within and on the body last? How much of a time difference would it be, if any, between say an ant and a blue whale?

submitted by /u/zincinzincout
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What are the repercussions of detonating a nuclear bomb underground?

Posted: 03 Sep 2017 10:56 PM PDT

When the immune system damages the gut of a coeliac person who eats gluten, does the mechanism of action differ significantly from that of an allergy (igE+histamine+basophils)?

Posted: 04 Sep 2017 05:18 AM PDT

Coeliac's is often described as an "allergy", but people who've been educated in the field say it's "technically not an allergy and technically not autoimmune, though very similar to both". I'd like to better understand what this means.

Bonus question: Do allergies have something similar to "levels" like coeliac's? Or is it more like you're either allergic or non-allergic?

submitted by /u/katinla
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How does one measure the thickness of gold foil?

Posted: 04 Sep 2017 06:03 AM PDT

What, other than the tides, is noticeably affected by the moon's gravity?

Posted: 03 Sep 2017 01:46 PM PDT

Why does the deficiency of some vitamins like b12 can cause depression?

Posted: 03 Sep 2017 07:48 AM PDT

Cats can shake their head at a surprisingly rapid rate. How do they avoid whiplash and concussions while doing this?

Posted: 03 Sep 2017 04:20 PM PDT

What is the mechanism by which nuclear reactors produce energy?

Posted: 03 Sep 2017 09:24 PM PDT

To be more specific, I'm interested in what happens with the nuclear fuel and how the energetic reaction is sustained. I know that it uses fission (commonly U-235) to release the energy, as well as the basic idea of neutron moderation, and I'm aware of but not fully versed on the idea of fast and slow neutrons.

My questions include: * Is the reaction a self-sustaining chain reaction? That is, could it be considered at the precipice of criticality? * Followup, if It is NOT, then how is the reaction maintained? How do they provide enough neutrons for a sustained and fairly constant energy production? * How exactly are the decay products handled? How quickly do they accumulate? And what do they do to the energy output? (Also, if possible, the common and notable decay products would be awesome!) * How does "neutron moderation" occur, and what is the point of it? My picture of the reaction is of solid fissile fuel (i.e. like those diagrams you see explanation fission). Where does the moderator interact with the fuel?

I hope these questions make sense! My understanding of physics is analogous to that of a hobbyist astronomer, so explaining it at that level is ideal. However, I'm fairly content with getting into more mathematical sides of things if necessary. That said, these questions are more of the engineering side (which is the category where I'm placing it), so I'm hoping it will have more conceptual answers.

submitted by /u/Aethi
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How exactly can elements be changed into other elements by radiation?

Posted: 03 Sep 2017 03:17 PM PDT

If I remember correctly, the radiation of electrons can disturb and add/take away electrons from another element to change the element itself. If I were to do this to a big block of gold, could I possibly change this into a block of silver or even into a gas like oxygen?

submitted by /u/Bradleyharris88
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Could a neutron detector be used to verify underground nuclear tests?

Posted: 03 Sep 2017 11:53 AM PDT

If the symptoms of an illness are typically the body creating a hostile environment to get rid of the infection (runny nose, fever, etc.), what do viruses/bacteria actually do?

Posted: 03 Sep 2017 08:29 AM PDT

Or, what would an illness look like if our immune system didn't do all of those things to destroy the viruses/bacteria?

submitted by /u/mozrik
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How much of the fissionable materials (Uranium, Thorium) are in the Earth's core and how often does it combine into critical mass to explode?

Posted: 03 Sep 2017 10:25 AM PDT

How can waxing and waining gibbous phases of the moon look like they do?

Posted: 03 Sep 2017 03:22 PM PDT

The shadow the earth throws on the moon in those phases looks like the earth is a crescent instead of a sphere. I can't wrap my head around it. Can someone please explain.

pic of lunar phases

submitted by /u/I_want_fun
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Do trees effect the wind speed/potential wind damage of a hurricane?

Posted: 03 Sep 2017 03:35 PM PDT

With Hurricane Irma looming, I was wondering if living in a rural area with dense tree and brush coverage has any effect on the wind speed of the storm at ground level, and by extension could that reduced wind speed lessen the potential damage caused by the wind to homes in that area? Edit: of course, trees can fall and branches become projectiles, I'm more curious about wind damage only from a powerful major hurricane.

submitted by /u/DobbyDooDoo
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What is it exactly that energy boosting substances like caffeine and ginseng do to our body in order to provide an alert/energized state?

Posted: 03 Sep 2017 09:05 AM PDT

How is queen bee becoming a queen bee ? Is it natural or is it acquired ?

Posted: 03 Sep 2017 02:08 PM PDT

From the Light Side of the Moon, are there phases of the Earth?

Posted: 03 Sep 2017 06:28 PM PDT

What happens to the inside of planets as they age?

Posted: 03 Sep 2017 07:03 AM PDT

I was thinking about the Earth's core today and how they should, due to entropy, cool over time. However it will still be under enormous pressure. What happens to different planet's cores over time? Do they completely solidify? Similarly what will happen to gas giants as they age?

submitted by /u/SailingOnFishlessSea
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With regards to the Diving Reflex, can we hold our breath longer while underwater than we can on land?

Posted: 03 Sep 2017 07:48 AM PDT

Does Hurricane Harvey affect the weather for the rest of the United States? If so, how, and how far?

Posted: 03 Sep 2017 07:56 AM PDT

Sunday, September 3, 2017

Why do clothes feel crunchy when you air dry them, but soft out of the dryer?

Why do clothes feel crunchy when you air dry them, but soft out of the dryer?


Why do clothes feel crunchy when you air dry them, but soft out of the dryer?

Posted: 02 Sep 2017 04:57 PM PDT

Do animals like music? Or at the least, can they recognise the patterns, melodies etc. and react to them?

Posted: 02 Sep 2017 03:03 PM PDT

Why do some people outgrow allergies and some people develop them later in life? And why do some people never outgrow them?

Posted: 02 Sep 2017 05:11 PM PDT

Is there any way to determine the likelihood of whether someone will or won't outgrow their allergies? I feel like I can never find a solid answer to any of these questions.

submitted by /u/Lowfatmilksubstitute
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Did the construction of the Panama and Suez canals affect the ecology of the surrounding waters?

Posted: 02 Sep 2017 03:44 PM PDT

Despite the small overland distance, would connecting two very different bodies of water have a noticeable effect on the flora and fauna of the two regions?

submitted by /u/SpooningThemSoftly
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In light of recent events in North Korea, how do you set off a nuclear bomb underground without causing substantial damage above the blast site?

Posted: 03 Sep 2017 12:06 AM PDT

Reports saying that this was a hydrogen bomb and 10 times more powerful than anything ever previously tested and 5 times more powerful than the Nagasaki bomb which killed 70000 people almost instantly. How is there not like, y'know, a massive crater in the ground where it was or something?

submitted by /u/Farquad4000
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During a supernova, what amount of the star's matter is converted into energy?

Posted: 02 Sep 2017 10:56 PM PDT

It looks like during the lifetime of the sun, .034% of it's mass will be converted into energy via E=MC2. But what about a supernova? Perhaps we can use an A1 type as an example.

submitted by /u/Djerrid
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Can a star have more than one fusion core?

Posted: 02 Sep 2017 04:40 PM PDT

Other than supernova, could for example a blue supergiant/hypergiant have hotspots not in the center that cause fusion?

submitted by /u/UntamedOne
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How are parrots able to repeat and talk?

Posted: 02 Sep 2017 08:20 PM PDT

How are parrots able to memorize and repeat certain noises and words so well?

submitted by /u/stargazer547
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How does the Rfly drone based RFID system developed at MIT work?

Posted: 03 Sep 2017 05:57 AM PDT

The text in the article says:

The drones don't actually carry the RFID reader with them — Adib explains that this added weight basically caused the drone to crash — but rather, relays the signals emitted by the reader over larger distances. "You can take a single reader, whose range is limited to a few centimeters, and send the signal over exponentially larger distances."

So does this mean that the drones are just repeater/amplifiers? Does the reader have that much more bulk? What if two drones transmit the same reader signal and send back the RFID codes at the same time, are there multiple readers waiting for the signal? Do different drones operate on different frequencies?

submitted by /u/snarejunkie
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Is the Planck length constant or does it change as the universe expands?

Posted: 02 Sep 2017 02:31 PM PDT

Also, is space time pixelated by this length, or could you have overlapping of said pixels or lengths, where space-time is actually continuous?

Edit: The title should read "....could it possibly change..." as it might be theoretical.

submitted by /u/jstaylor01
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Does a satellite experience centrifugal force or centripetal force?

Posted: 02 Sep 2017 06:17 PM PDT

Does the quantity or quality of melanin in our skin change as we age?

Posted: 02 Sep 2017 05:17 PM PDT

Is there radiation associated with the creation of a charged particle?

Posted: 02 Sep 2017 06:20 PM PDT

I was studying for E&M and I noticed that radiation fields seem to be accompanied by a changing current somewhere. I then tried to figure out how to get radiation without a current this is the best I got. I know the question is kind of nonphysical since you can't just create a lone electron for example but supposing you could, does that release radiation? I'm assuming there's some delta function like object but I'm not sure.

I recognize that this is kind of a silly question but I wanted to procrastinate and nobody else is in the office with me.

submitted by /u/MarsOfDickstruction
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How does speakers make multiple frequency at once?

Posted: 02 Sep 2017 05:01 PM PDT

So I understand that a speaker oscillates to a specific frequency but how is possible for it to make a mixtures of highs and lows at once

submitted by /u/princehermit
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Why is a kettle so much more efficient than a saucepan at boiling water?

Posted: 02 Sep 2017 10:59 AM PDT

Can someone explain the comparative strength of household magnets?

Posted: 02 Sep 2017 06:18 PM PDT

I'm interested in making household (i.e., refrigerator) magnets as a craft project by gluing some gewgaw to a plain, ordinary magnet. The plasticky "magnet tape" is notoriously weak, and the hard black ones are too big, so I ended up with some neodymium magnets from the hardware store. After some reading, I am worried that these are too strong and may be difficult to remove from a refrigerator without tearing off the gewgaw. Internet research is just getting me a lot of industrial supply company FAQs and Wikipedia articles with tesla measurements. I don't even know what a tesla is a function of: mass of the magnet? area of the pole? something more esoteric? I would appreciate a quick-n-dirty guide comparing household magnet types in some sort of strength-for-size way. Thank you!

submitted by /u/SciviasKnows
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What determines the boiling and freezing points of a substance?

Posted: 02 Sep 2017 03:51 PM PDT

Is there a difference in sound quality when I use the volume control wheel (a variable resistor, I assume) on my headphones as opposed to changing the volume through software?

Posted: 02 Sep 2017 11:19 AM PDT

I understand that it would not necessarily be a noticeable difference; however, is one method of volume control superior in any way? Is it better leave the software volume at its maximum and lower the headphone control as needed, or vice-versa?

submitted by /u/Thundershock97
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Need help Understanding JFET's, Specifically how the depletion region is controlled and its relationship to drain current?

Posted: 02 Sep 2017 01:58 PM PDT

So we just started studying FET's in my Electronics circuits and device theory class, I have a basic understanding of how N-channel JFET's work.

I am having trouble wrapping my head around how the depletion region is affected by VDS/Drain current when VGS is set to 0V. I think the larger the drain current(ID) becomes the more free electrons are "pulled"(not sure if correct term) from the N-type making the depletion region have more positive ions. I am trying to understand what is physically happening in the depletion region when VGS=0 and ID increases.

I also want to understand the other side, Where ID is a function of VGS, How does applying a larger negative voltage make the depletion region larger and how does that effect the resistance of the N-channel.

What is the difference between the depletion region when VGS=0 and ID is at saturation compared with VGS= Some negative value and ID = some lower saturation current. What physically happens to the charges in the depletion region?

I can clarify if what I'm asking is unclear.

submitted by /u/eoin34
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Why do some things burn and some things melt?

Posted: 02 Sep 2017 11:05 AM PDT

Saturday, September 2, 2017

Does language affect the way a person's vocal chords develop?

Does language affect the way a person's vocal chords develop?


Does language affect the way a person's vocal chords develop?

Posted: 01 Sep 2017 05:58 PM PDT

Is there a limit to how many elements there can be?

Posted: 02 Sep 2017 04:09 AM PDT

What was the weather like in northern parts 13,000 years ago that humans would consider and make the trek from Asia to NA?

Posted: 02 Sep 2017 06:31 AM PDT

Are we capable of fission reactors for electrical space propulsion?

Posted: 02 Sep 2017 05:21 AM PDT

Considering future interplanetary exploration using electrical engines we will need powerful and efficient electrical power sources. As far as I know solar panels are not capable of supplying a mass per kilowatt efficiency required by power heavy engine types like MPD arcjet or Vasimr, especially for the exploration of the gas giants.

Would proper fission reactors (other than the weak RTGs) be feasible in our current technological and industrial capabilities? Or are they currently science fiction?

submitted by /u/88880
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How does electricity get to the load with AC?

Posted: 02 Sep 2017 04:54 AM PDT

Hello reddit,

first of, English is not my native language, so my apologies in advance if I make any mistakes.

I'm an electrical engineering student but I haven't really understood how the electricity gets to the load with alternating current.

I know that with AC, the polarity changes (50Hz in Germany), so the electrons sort of "vibrate" back and forth, therefore they basically stay in the same place.

I've read that not the electrons, but the electric field is the important factor. I just don't understand how the electric field makes the electrical load (correct term? The device that should be powered) work. How does the load get the electricity it needs?

Edit: I've read that the "vibrating" electrons create energy. But what kind of energy? And how does it get to the load? Also, if the electrons aren't really "used" by the load, how does DC work? The electrons flow to one direction, so they have to flow "into" the load at some point. What happens to the electrons then?

I would appreciate some help very much! Sorry if this questions has been answered before.

submitted by /u/SirJoey
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Is motion relative even at the quantum scale?

Posted: 02 Sep 2017 04:31 AM PDT

Do dogs know that cats are cats?

Posted: 01 Sep 2017 05:35 PM PDT

I know that dogs can differentiate between humans and other dogs, and that cats think that humans are essentially weird cats, but do we know what dogs think of cats?

submitted by /u/Thug_Mustard
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Is an electrocardiogram sensing actual current or an electromagnetic field?

Posted: 01 Sep 2017 08:14 PM PDT

I think that the ECG is sensing current, since you need the wet electrode pads and skin impedance is an issue.

I know that the action potential in the heart is created by sodium ion movement through cardiac tissue, which would create an electromagnetic field, but how does that create a current that would travel to where the electrodes are?

Is there some influence on electrons outside the heart that the ECG is sensing? I hope I made my question clear, thanks for taking the time!

submitted by /u/TotallyNotNew
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Have we contaminated space with life from earth?

Posted: 01 Sep 2017 05:48 PM PDT

For example, do we know if the Voyager probes or the Curiosity rover did not carry (living or dead) bacteria, viruses, or other microorganisms (e.g. tardigrades) into space or other planets? Are there normally steps taken before launch to prevent this?

submitted by /u/TrainFan
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Can particles still be entangled when one of the pairs is in a black hole?

Posted: 02 Sep 2017 02:17 AM PDT

If you could detect and measure Hawking radiation, could you tell what was inside of the black hole?

Posted: 01 Sep 2017 10:06 PM PDT

How do astronomers and organizations like NASA determine characteristics of exoplanets such as wind speed and weather?

Posted: 02 Sep 2017 12:41 AM PDT

What holds the nucleus of an atom together?

Posted: 01 Sep 2017 02:40 PM PDT

How does someone develop an allergy?

Posted: 01 Sep 2017 04:32 PM PDT

How does the collapse of a star decay the protons and electrons into neutrons?

Posted: 01 Sep 2017 12:53 PM PDT

So the basic idea of the birth of a neutron star is that the incredibly massive ball of H, He, and other material implode to become a supernova after millions of years in fusion reaction as it consumed and fused the light fusion material into heavier matter. In this 10 seconds the protons and electrons are transmutated into neutrons. But how?

What happens to the particles in the supernova from a particle physics standpoint? Electrons by themselves cannot be made into neutrons since they are leptons, right?

And also why is it that it are specifically neutrons that are favored in this event?

Thank you for reading, and thank you in advance. Cheers!

submitted by /u/88880
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Potentially stupid question, would it be possible to surgically insert magnets into the stumps of people who has lost hands to allow them to pick up metal objects easier?

Posted: 01 Sep 2017 01:50 PM PDT

Is it possible to make a light source that emits an equal intensity of every visible wavelength? Why or why not?

Posted: 01 Sep 2017 12:11 PM PDT

When having children do you physically pass on a piece of your DNA or is a copy of your DNA somehow made and passed on?

Posted: 01 Sep 2017 06:03 PM PDT

DNA is an actual physical thing, right? So if it has a physical shape, what do you guys think?

submitted by /u/T4blespoon
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Will the electrons in the wire of the generator run out?

Posted: 02 Sep 2017 12:00 AM PDT

This sounds like a dumb question. I'm a teen and from my understanding in class. Electricity is produced by cutting a conductor through a magnetic field to "push" the electrons. So when we us electricity, will the electrons be used up and you have to change the metal in the generator or the electrons are still there but just the energy they carry is transferred. I asked my teacher and all he said was "It isn't in the syllabus, don't bother"

submitted by /u/poi_slayer
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