Pages

Monday, June 5, 2017

Why don't humans have mating seasons?

Why don't humans have mating seasons?

Why don't humans have mating seasons?

Posted: 05 Jun 2017 01:28 AM PDT

Hummingbirds flap their wings around 70 times per second during normal flight...what is the fastest natural movement that humans are capable of, either voluntary or involuntary?

Posted: 04 Jun 2017 07:48 AM PDT

My daughter was watching a cartoon on PBS this morning and they were talking about pollination. It was mentioned that hummingbirds are capable of flapping their wings upwards of 200 times per second. After a quick google, it seems 70 is the more common number for "normal" flight. That's obviously still extremely fast and made me wonder what humans are capable of in terms of pure speed, so I thought I'd ask here.

submitted by /u/imTHATitguy
[link] [comments]

what, precisely, is the difference between a dipole-dipole interaction and a "hydrogen bond"? Why is a hydrogen bond (a) different and (b) stronger?

Posted: 05 Jun 2017 05:08 AM PDT

People typically just give the reason that it's the electronegativity difference. But that's wrong - HCl does not show hydrogen bonding - just look at the boiling points - it's very clear that only HF, H2O and NH3 have hydrogen bonding here. There's a huge offset from the rest of the trend because of them. CLEARLY the electronegativity is not the full story, because HCl is not showing anything off-trend in that plot, yet has a bigger electronegativity difference than NH3 does.

I went down the rabbit hole of thinking it was because it had to be period 2 elements - because then they were smaller and therefore had a better orbital overlap with hydrogen, creating a stronger bonding interaction. But NOPE. That's not the explanation either. I found some chem papers floating around that are talking of hydrogen bonding in H2S. WTF? I look on wikipedia and see that hydrogen bonds are supposedly why water gets such a high boiling point whereas H2S doesn't, because H2S doesn't hydrogen bond.

Um. GUYS. Does it or doesn't it?? wtf even IS a hydrogen bond anymore?? if it's just a dipole-dipole thing then why have its own name??! and what's the deal with water's boiling point?? if it ISN'T just that then what IS it? what differentiates it?

I find it maddenning that literally nowhere clarifies this. All it EVER says is lists molecules that hydrogen bond and ones that don't, and states NO REASON why those specific ones do or don't or what the flipping difference is supposed to be. WHATS THE DIFFERENCE?

FOR example. How do I tell whether the electrostatic interactions in HS are hydrogen bonding or not?

BEYOND something vacuuous like "oh it's a sulfur therefore we don't call it that". There are papers out there that DO call it that.

submitted by /u/usernumber36
[link] [comments]

Does water have a high heat capacity because it is a polar molecule? Do all polar molecules have high heat capacity?

Posted: 04 Jun 2017 05:48 PM PDT

How does a pencil eraser work?

Posted: 04 Jun 2017 05:51 PM PDT

Chemically or mechanically, what happens when an eraser rubs off lead/graphite from a paper? Why doesn't this work for, say, ink?

submitted by /u/Khenghis_Ghan
[link] [comments]

Why does water form little spheres when thrown in the air, versus just spreading out into a random blob?

Posted: 05 Jun 2017 06:42 AM PDT

Has the string theory been validated by any experimental evidence like from the LHC?

Posted: 05 Jun 2017 03:45 AM PDT

Are there better contenders for the theory of everything?

I know just the basics of what the string theory is, that is using vibrating strings and extra dimensions to explain all the different forces and particles. I come from a medical background, so please excuse any gross misunderstandings of the concept.

submitted by /u/zorbix
[link] [comments]

What's the current state of Thorium Molten Salt Reactor research?

Posted: 04 Jun 2017 09:46 AM PDT

From time to time talk about Thorium / Molten Salt Reactors pops up as possible solution to our energy problem. As far as I can see it's far away from being well-funded research nowadays. Can someone explain why we put billions into fusion reactor research and not closely enough into Thorium / Molten Salt Reactor research? Also: What is the current state of research? How far would we realistically be away from having such reactors?

submitted by /u/hdsjulian
[link] [comments]

How common is prion resistance/immunity in humans?

Posted: 04 Jun 2017 09:21 AM PDT

I have general anxiety disorder, and recently I have been losing sleep over a prion phobia. So, how common is genetic resistance to prion disorders in humans? Specifically, my family is of southern Chinese background, and I would like to know if prion resistance would be common in a typical southern Chinese genotype. Thank you.

submitted by /u/HappyDaysInYourFace
[link] [comments]

How are percent chances of rain, storms, etc. determined?

Posted: 04 Jun 2017 05:26 PM PDT

I'm curious to learn how those percentages are determined, and why they vary from station to station.

I also would like to know why we can't be more exact and how "surprise" storms occur with little to no warning.

submitted by /u/knine1717
[link] [comments]

Does increasing orbital angular momentum cause electromagnetic radiation to travel slower through a material?

Posted: 05 Jun 2017 04:19 AM PDT

Or rather, can you cause electromagnetic radiation to have more interactions with a material before leaving by increasing its OAM?

submitted by /u/RevEngineer_11
[link] [comments]

What happens when Thermite burns asphalt?

Posted: 04 Jun 2017 05:03 PM PDT

I was watching videos on the Battle of Britain, more so memoirs of those involved. And recalled a documentary mentioning the allies use of thermite bombs in cities during late war. Can't remember the documentary though.

Even if not historically true, what would happen to Asphalt when burned by thermite?

Thanks

submitted by /u/Toads45
[link] [comments]

Does the density of air change in a controlled volume, if we change the temperature inside the box?

Posted: 04 Jun 2017 08:21 AM PDT

Since density is mass over volume, and the mass isn't changing, and the volume isn't changing, does the density of air not change?

submitted by /u/bush_did7-11
[link] [comments]

Can energy be generated through the color force?

Posted: 04 Jun 2017 06:04 PM PDT

Generating usable energy seems to be done by exploiting one of the four fundamental forces. Gravity can be harnessed by dams, electromagnetism by chemical reactions such as the combustion of gasoline, the weak nuclear force through fission, and the strong nuclear force through fusion. I realize that the strong nuclear force and color force are fundamentally the same interaction, but they are distinct. Matter can be created by applying energy trying to separate quarks due to confinement, is the reverse possible?

submitted by /u/mattbros
[link] [comments]

How does the huge arch over Chernobyl work?

Posted: 04 Jun 2017 09:43 AM PDT

How does it keep radiation from getting out? Will it help the surrounding area or just keep the reactor from contaminating it more? Is it actually worth it if it's only going to last 100 years, when the radiation will last hundreds of thousands of years?

submitted by /u/PetersPickleParking
[link] [comments]

At whitch speed would you hit/be hit by the fewer amount of rain drops?

Posted: 04 Jun 2017 07:27 AM PDT

I seek how to demonstrate the answer. Thank you =)

submitted by /u/Lifender
[link] [comments]

What sort of symptoms of radiation poisoning (if any) can be seen in plant life?

Posted: 04 Jun 2017 06:30 AM PDT

Will denser objects sink forever?

Posted: 04 Jun 2017 02:00 AM PDT

If you hve an infinite column of water and place an object denser than water in it, will that object sink forever?

I don't think it will because if pressure inside the water is pgh, then there must be some height h where the pressure balances out the pressure exerted by the object and the water on top, right?

Say water area is A, density is 1, and height is H. And object area is A, density is 2, and height is h. And gravity g is 10.

So if the object is in the water, it displaces the water on top. So now there is water on top of the object, and the water below the object feels the force of both weights.

Force of water on top of object is 1AH*g = 10AH.

Force of object is 2Ah*g = 20Ah

Adding both forces gives 10AH + 20Ah.

Pressure is force/area, so we get (10H + 20h) for pressure.

Is there any height in the water column that will support this pressure and prevent sinking?

submitted by /u/yosimba2000
[link] [comments]
vào lúc No comments:

Sunday, June 4, 2017

Is gravity weaker on the equator just because the radius is larger, or also because of a centrifugal force?

Is gravity weaker on the equator just because the radius is larger, or also because of a centrifugal force?

Is gravity weaker on the equator just because the radius is larger, or also because of a centrifugal force?

Posted: 03 Jun 2017 02:49 PM PDT

And if a centrifugal force also has an effect, how large is it compared to the difference in radii?

submitted by /u/vanavv
[link] [comments]

Why is infrared radiation usually associated with heat even though UV, X ray, and gamma radiation are much higher energy?

Posted: 03 Jun 2017 09:48 AM PDT

Why do we build larger particle colliders with bigger diameters instead smaller diameters traveled multiple times?

Posted: 04 Jun 2017 05:08 AM PDT

The question came up after this article discussing the successor to the Large Hadron Collider.

submitted by /u/Schlaefer
[link] [comments]

If we mined the moon, how much could we extract before it's orbit started to decay?

Posted: 03 Jun 2017 09:58 PM PDT

About 20 ants are sitting still in a group on my ceiling. Is this behaviour normal?

Posted: 03 Jun 2017 06:42 PM PDT

I live in Auckland, New Zealand and last night i noticed a group of ants huddled together on the ceiling not moving. After being disturbed they only dispersed very lightly. There was no evidence of a food source or hole leading somewhere. After about 14 hours they are still there. Is this behaviour normal? Either way, what is causing it?

Here is a picture: http://imgur.com/AJ1OXCQ

Thanks

submitted by /u/ghostapplejuice
[link] [comments]

Can we accurately (+/- 1 C) predict the weather one month ahead assuming we have the access to enough computational power?

Posted: 04 Jun 2017 12:00 AM PDT

I was reading recently about struggle for computers and humans to generate truly random numbers. It seems like there is no random stuff happening in the nature. Yet, still my weather forecast is sometimes horribly wrong. It appears to me, that since humanity was improving their weather forecasting skills for thousands of years, we should be pretty much good at it.

Assuming we have access to all computational power we need, can we predict the temperature in every location on Earth for every point of time one month ahead?

submitted by /u/Kukis13
[link] [comments]

How do you measure the most accurate measurement devices?

Posted: 03 Jun 2017 09:58 AM PDT

Or more simply, if I have access to a device that measures something with a certain, known accuracy, and I have a device with an unknown accuracy that I expect to approach that of my known device, what sort of math should I be doing statistically? How is this generally handled in science/engineering?

Edit: there's been one cool answer which is measuring something different that you correlate using scientific theories. However, that doesn't really explain my original (intended) question of what you do when you're measuring the SAME property directly.

submitted by /u/anprn
[link] [comments]

Are viscosity and surface tension of liquids effected by their temperature?

Posted: 04 Jun 2017 01:25 AM PDT

Does, for example, water have a lower surface tension when it is closer to its boiling point and the molecules are beginning to speed up and act similar to gas molecules?

submitted by /u/Acuity_Or_Inability
[link] [comments]

What is the pysical meaning of a matrix determinant?

Posted: 04 Jun 2017 04:58 AM PDT

The wikipedia page is being mysterious:

In linear algebra, the determinant is a useful value that can be computed from the elements of a square matrix.

Yeah, I can compute all sorts of neat values from a square matrix, why do we need a special name for it?

Now, I understand, say, eigenvectors: it's a vector that doesn't change direction when multiplied by the matrix. Ditto for eigenvalues, inverses, etc... all of them have neat descriptions of what they mean qualitatively. Yet the only tangible difference between matrices of different determinants depends on whether or not the determinant is zero. What's the big difference between a matrix of determinant 1 and determinant 2?

submitted by /u/thetimujin
[link] [comments]

Why does molten metal loses its electromagnetic properties?

Posted: 03 Jun 2017 09:23 PM PDT

Can heat travel through vaccum?

Posted: 04 Jun 2017 12:37 AM PDT

If no,then they can replace the insulator in that hot and cold bottles

submitted by /u/jenith25
[link] [comments]

Why dont my headphone wires attract metals if magnetism is caused by the flow of electrons?

Posted: 04 Jun 2017 04:03 AM PDT

Is it possible to move through the overlapping event horizons of two nearby black holes?

Posted: 03 Jun 2017 05:56 PM PDT

And if so, what is this area called? I'd think it'd be something like a Lagrange Point, but not sure.

submitted by /u/Lokarin
[link] [comments]

Would more salt dissolve in hotter water heated under higher pressure? what's the limiting factor stopping more salt from being dissolved at greater and greater temperatures and pressures?

Posted: 04 Jun 2017 06:45 AM PDT

At what rate does a wake move in relation to the boat creating it?

Posted: 04 Jun 2017 02:49 AM PDT

Why do some stars produce four lines that protrude from the star whenever a photograph is taken from them?

Posted: 03 Jun 2017 05:06 PM PDT

Since gravity is weaker at the equator, why wouldn't we launch all of our rockets from there?

Posted: 04 Jun 2017 01:11 AM PDT

Does the size of spheres alter the void fraction in a close packing system of a fixed volume container?

Posted: 03 Jun 2017 01:49 PM PDT

Basically, I'm looking at water content in a foam (void fraction), where bubbles of similar size behave in some way like a close packed system of spheres.

My question is, as the bubbles in the foam get larger, (while the cylinder the foam is flowing in remains fixed), does this affect the void space theoretically?

submitted by /u/kewldude69
[link] [comments]

If mass can't be created, how do trees and plants grow from tiny seeds ?

Posted: 04 Jun 2017 12:55 AM PDT

Seeds create trees and fruit etc. If mass cant be created how can so much come from something as small as a seed ?

submitted by /u/andydeerfc
[link] [comments]

How far does the infrared of a remote reach?

Posted: 04 Jun 2017 04:02 AM PDT

Hello

I'm trying to mess with some projectors using my phone but I was wondering what the reach is for common infrared remotes Like how many meters of air/concrete/glass can it penetrate and still be useful? The projectors I'm interested in are acers and dells. My phone is a LG G5 SE (european model).

submitted by /u/tomanythrowaways99
[link] [comments]

How far "up" do you need to be in order to see earth spin below you?

Posted: 03 Jun 2017 03:13 PM PDT

I thought of the question why the earth doesn't spin below helicopter hovering still in the air and learned that the air of earth moves along with it. So how high up do you need to be in order to see the earth spin below you?

submitted by /u/Knight-Jenerik
[link] [comments]

Why can we see light through our eyelids when both are closed, but not when only one is closed?

Posted: 03 Jun 2017 05:44 PM PDT

Close both your eyes and stand with a light to your right side. Now wave your hand over your right eye. You'll see the shadow of your hand through your eyelid, blocking the light.

Now open your left eye.

You can no longer see the "red" coming through your right eyelid, and there's no difference in light/coloration when you wave your hand in front of it. It's not picking up any of the light anymore.

Why/how does this happen?

submitted by /u/LinksGayAwakening
[link] [comments]

What makes the complex plane so convenient to express the Mandelbrot set with?

Posted: 03 Jun 2017 03:13 PM PDT

I understand you cannot simply substitute the complex number in x2 + c with (x,y) and get the same results, since the "y", or rather, the Imaginary axis of the complex plane functions differently than it's "x" or Real axis. But I don't have an intuitive enough sense of this difference to know why a formula for the Mandelbrot set can't be expressed so simply on a simple coordinate plane using only real numbers.

I'm sure my phrasing betrays a lot more about what I misunderstand than what I understand, so if my question doesn't even make sense, then please help me clear up my initial misunderstandings!

Thanks.

submitted by /u/Sophilosophical
[link] [comments]
vào lúc No comments:

Saturday, June 3, 2017

On Jupiter, will more superstorms the size the Great Red Spot eventually form, or are the positions and types of storms relatively constant?

On Jupiter, will more superstorms the size the Great Red Spot eventually form, or are the positions and types of storms relatively constant?

On Jupiter, will more superstorms the size the Great Red Spot eventually form, or are the positions and types of storms relatively constant?

Posted: 02 Jun 2017 02:56 PM PDT

Hurricanes and big storms on Earth move around and change size, but does that happen on Jupiter?

submitted by /u/50PercentLies
[link] [comments]

When humans wanted to first fly to space how did we know that we needed space suits to survive?

Posted: 02 Jun 2017 04:10 PM PDT

How probable is it to get a computer error due to quantum effects?

Posted: 03 Jun 2017 04:12 AM PDT

As far as I understand, transistors nowadays are small enough that quantum effects become relevant. I'm hesitant to use words like quantum tunneling or energy wells because I don't fully grasp these concepts, but as I learned it it's possible for a quantum particle to escape its "cage" if the energy level is low enough or something.

Could this effect cause errors, corrupted data, a bluescreen, etc.?

submitted by /u/KindaOffKey
[link] [comments]

If 3-phase is more efficient, why isn't everything 3-phase?

Posted: 03 Jun 2017 01:18 AM PDT

I was reading on the difference between 3-phase and 1-phase power, and I got that 3-phase has 3 wires + neutral, and 1-phase has 1 wire + neutral. Some sites I was reading on that 3-phase is more efficient and uses less conducting material, but it's primarily used for industrial purposes. Residences stick to 1-phase. If it's more efficient and uses less materials, why then isn't everything in a 3-phase setup? What's the drawback to 3-phase that keeps 1-phase relevant.

submitted by /u/zerosaver
[link] [comments]

Why is the environmental community focused so heavily on CO2 emissions when methane is 30 times more effective at trapping heat in our atmosphere?

Posted: 02 Jun 2017 08:13 PM PDT

Correct me if I'm wrong, but wouldn't cutting the USA's atmospheric methane contribution by 50% offset our CO2 output by more than 100%? If so, why are we focused on carbon footprints rather than methane footprints? https://www.epa.gov/ghgemissions/overview-greenhouse-gases

submitted by /u/NatureNate19
[link] [comments]

To a photon, dose it takes a year to travel one "light-year"?

Posted: 03 Jun 2017 01:49 AM PDT

How do we know that gas giants are made of gas?

Posted: 02 Jun 2017 05:11 PM PDT

And is it possible for there to be a surface on a planet such as Jupiter?

submitted by /u/12isbae
[link] [comments]

Do mirrors reflect all of the EM spectrum? WiFi, IR, UV, radio, etc.

Posted: 02 Jun 2017 07:17 PM PDT

We appreciate ourselves in mirrors, but that's only a small part of the spectrum. Can my bathroom mirror increase my WiFi range in a single direction? Could I make a small area hotter with a concave mirror and candle?

submitted by /u/shibbster
[link] [comments]

How does a spacecraft Measure its speed in orbit around a planet?

Posted: 03 Jun 2017 02:20 AM PDT

So I was just watching an episode of sci-show space, where they talked about the Juno probe and the work it is doing while orbiting Jupiter.

They mentioned that one of its jobs is to map the gravity field of the planet, and it does this by detecting speed changes in the orbiter, with higher speeds meaning higher gravity.

How does a probe such as Juno measure its orbital speed to such accuracy that it can accurately map the gravity field around Jupiter? It isn't like it has GPS out there.....

submitted by /u/Cr3s3ndO
[link] [comments]

How much more intelligent are we than our ancestors? I understand we have advanced as a society greatly but how much has the average intelligence of humans changed in the past 20,000 years?

Posted: 02 Jun 2017 02:30 PM PDT

If you were to drop a small insect, such as an ant or a grasshopper without the ability to fly, from a high latitude like the Empire State Building, would it die? Why it why not? May be a stupid question but my reasoning below, albeit illogical

Posted: 02 Jun 2017 09:15 PM PDT

For some reason I imagine that due to such small body mass, insects couldn't possibly suffer crucial injuries. It can't be proportional to their size, I just knocked a banana bug off the counter and that thing was tiny as hell, that'd be like knocking me off a three story building. Yes I'm drunk but I'm genuinely curious because I've always wondered this

submitted by /u/HaleyCenterLabyrinth
[link] [comments]

How do birds know to make nests? Is it purely instinctual or is it taught?

Posted: 02 Jun 2017 10:59 AM PDT

I was watching a gull collect moss for its nest earlier today and began to wonder how they know how to construct their nest. I have seen many birds building their nests but I haven't seen any birds teaching their young. This behaviour seems to be from instinct, but surely this is too complex to be just an instinct.

submitted by /u/mightierjake
[link] [comments]

If you're traveling 100 mph in one direction and shoot a bullet backwards at some enemy/target, will the momentum of the bullet be affected?

Posted: 02 Jun 2017 11:15 PM PDT

Do countries with higher taxes tend to have better quality of life?

Posted: 02 Jun 2017 04:41 PM PDT

Here is a list of countries by GDP to government revenue ratio. These numbers show what the government actually gets, rather than what it's asking for. In other words, it doesn't take in to account tax evasion.

I'd like to find out if indexes for development and quality of life and so on are correlated with higher taxes. It may be that countries with higher quality of life have more capable governments which are able to achieve higher GDP to government income ratio by being more effective at fighting tax evasion, despite asking for less in taxes than weaker governments.

Essentially I'd like to know the answer to "Do higher taxes correlate with higher quality of life?", rather than "Does higher government income as a percentage of GDP correlate with higher quality of life?". I'd look to do it by actually have the dataset myself, but if someone has already answered this question for me, I guess that will do.

submitted by /u/Freeloading_Sponger
[link] [comments]

How do scissors work?

Posted: 02 Jun 2017 06:26 PM PDT

If you cannot split atoms, then are you splitting the bonds between them, if so how come a sharp blade specially can cut it and not a dull blade (you get the point [no pun intended, I'm not sharp {pun intended}])

submitted by /u/Aperture_Creator_CEO
[link] [comments]

Burning fossil fuels also releases a lot of wasted heat. If this is not accounted for in warming projections, where does it all go?

Posted: 02 Jun 2017 06:19 PM PDT

Are non-atomic solids possible?

Posted: 02 Jun 2017 02:33 PM PDT

What prevents other subatomic particles from grouping together in a way that creates something with solid properties? I suppose that's a bit ambiguous, so here's what I mean by "solid":

  1. The subatomic particles stay together as a group spatially.

  2. These groups are repelled by similar groups, so they can't occupy the same space as another group. This is similar to the van der Waals force.

submitted by /u/mike_bolt
[link] [comments]

How bright a light bulb needs to be to be seen from orbit?

Posted: 02 Jun 2017 07:05 PM PDT

How many/much brightness/power/lumens a light bulb needs to be to be seen from orbit? lets say from the ISS?

how a 100W lamp would be seen from the ground?

submitted by /u/rBeowulf
[link] [comments]

Why does hot air blown from a fan feel cold?

Posted: 03 Jun 2017 12:39 AM PDT

How do hive-minded bugs (ants, termites, bees) evolve if the queen is the only one passing on genes? Wouldn't this create in effect a sort of inbreeding?

Posted: 02 Jun 2017 02:53 PM PDT

Is it possible for two sounds two cancel each other out?

Posted: 02 Jun 2017 09:41 AM PDT

How do bee-eater birds bee-proof themselves?

Posted: 02 Jun 2017 03:24 PM PDT

How do bee-eating birds protect themselves from being stung by the bees they eat or other bees avenging their comrade (if bees do that)?

submitted by /u/Mightymcc
[link] [comments]

Why don't we have high resolution video of any of the planets?

Posted: 02 Jun 2017 03:10 PM PDT

Unsure if this is the correct place to inquire.

High resolution photos exist, why not video?

My question derives from the "Jupiter fly by" video currently on the front page

Any and all responses appreciated !!

submitted by /u/mr_reliable
[link] [comments]

How much do we know about how endocrine disruptors affect menopause?

Posted: 02 Jun 2017 07:32 AM PDT

I have managed to find a few articles: Menopause arriving early

Stronger hot flashes from phthalates

Missing studies on cosmetics

Women have a higher sick leave than men in my country (Norway), and I think all over the world? Some of this is connected to pregnancy, some of it to women being lower down in the hierarchy at work, but is some of it connected to endocrine disruptors affecting women more? Is there a connection between how these substances affect us and the fact that most autoimmune diseases affect women more often than men?

Here is some research (controversial) that shows that it is not only through mouth these chemicals are, but some think that also through touching, such as playing on the floor, can absorb endocrine disruptors.

It seems that in the US women often have menopause symptoms for ten years. That just doesn´t seem very natural. Scientists have been asking for stricter regulation, but I think the knowledge about these things are very little in the regular population, and I also have problems finding relevant research.

Please help me finding research.

submitted by /u/Toove
[link] [comments]
vào lúc No comments:
Subscribe to: Posts (Atom)