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Monday, July 25, 2016

Is there any difference between the weightlessness experienced while in orbit and in the middle of space?

Is there any difference between the weightlessness experienced while in orbit and in the middle of space?

Is there any difference between the weightlessness experienced while in orbit and in the middle of space?

Posted: 24 Jul 2016 03:04 PM PDT

Do sealed, airtight goods generally appear more inflated in Denver than (say) Miami because of the difference in pressure, or is the effect too small to notice?

Posted: 24 Jul 2016 11:47 AM PDT

What causes hair to "get used to" being combed or done a certain way after awhile?

Posted: 24 Jul 2016 08:25 AM PDT

If changing direction is considered acceleration, how does light not accelerate when bending in a gravitational field?

Posted: 24 Jul 2016 11:46 PM PDT

Light travels at a constant speed and that cant change, so how does this work?

submitted by /u/Yobleck
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What is the rate of energy transfer through tidal friction?

Posted: 25 Jul 2016 07:16 AM PDT

The Moon 'drags' the oceans around the Earth which transfers kinetic energy from the moon to the earth in the form of heat through the friction. What is the power (energy per unit time) associated with this effect?

submitted by /u/DanielDC88
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How do silent heart attacks work?

Posted: 25 Jul 2016 04:54 AM PDT

Many people have had heart attacks with little or no symptoms and then continued on with their lives, none the wiser. My question is, how does this work? By that I mean, if the vessel is blocked and the heart muscle is dying, why does the heart attack not continue until they die? Is it that there is enough blood for some but not all of the tissue so part of it dies and the rest then lives?

submitted by /u/acromulent
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why is coulombs law inaccurate for experiments done with small separation distances?

Posted: 24 Jul 2016 06:54 PM PDT

as the title states, I'm not sure why a small separation distance would affect the accuracy of coulombs law. Is it not accurate no matter the distance of the point charges?

submitted by /u/whiterabbil
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What differentiates the thought of doing something (e.g. moving your arm), and actually doing it?

Posted: 24 Jul 2016 09:27 PM PDT

How does your brain know whether or not to move your arm?

submitted by /u/Jofo24
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Why does wine taste "better" the longer it's aged? What is happening to the actual flavour?

Posted: 24 Jul 2016 07:41 PM PDT

Why are Polio and Smallpox eradicated while other commonly vaccinated diseases like MMR or Hep B aren't?

Posted: 24 Jul 2016 08:40 AM PDT

How do we predict that there will be an "island of stability" higher up in the periodic table? Is there a maximum size for atoms?

Posted: 24 Jul 2016 09:16 PM PDT

What are some of the potential applications of quantum computing?

Posted: 24 Jul 2016 12:53 PM PDT

I thought this might be a fun question to hear what everyone has to say. Also, first post on this subreddit! :)

submitted by /u/fakecodewriter
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How does an expectorant work? specifically ginger and honey?

Posted: 24 Jul 2016 07:20 PM PDT

What actually happens in the body that makes ginger and honey expectorants? Why does this work?

submitted by /u/acheleo
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Can light be deflected by light?

Posted: 24 Jul 2016 12:47 PM PDT

I was initially thinking about lightsabers deflecting lasers in star wars but wondered if it's even feasible.

submitted by /u/Kinda_Concise
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Can unstable atoms with a big nucleus be stabilized, if so how?

Posted: 24 Jul 2016 07:37 PM PDT

What causes some clouds to have a bottom that appears flat?

Posted: 24 Jul 2016 12:56 PM PDT

How do antivirus software scan password-protected archives?

Posted: 24 Jul 2016 10:09 AM PDT

If a compressed archive is encrypted with a password (.zip, .rar, .7zip etc), it is inaccessible. But how does antivirus software gain access to it regardless to scan it?

Edit: Thank you for the answers everyone!

submitted by /u/Sphyrwa
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Why does a Ferrari going 120 mph appear faster than a Boeing plane going 250mph?

Posted: 25 Jul 2016 12:03 AM PDT

Why the body temperature of chickens is so close to the temperature of denaturation of proteins?

Posted: 24 Jul 2016 09:52 AM PDT

The melting temperature varies for different proteins, but temperatures above 41°C (105.8°F) will break the interactions in many proteins and denature them. This temperature is not that much higher than normal body temperature (37°C or 98.6°F), so this fact demonstrates how dangerous a high fever can be.

Source: http://www.chemistryexplained.com/Co-Di/Denaturation.html#ixzz4FLUZOGC1

The internal body temperature of birds shows more variability than mammals, and therefore there is no absolute body temperature. In the adult chicken the variability is between 105°F and 107°F (40.6° and 41.7°C).

Source: http://www2.ca.uky.edu/poultryprofitability/Production_manual/Chapter7_Ventilation_principles/Chapter7_air_temperature.html

Is there a something special about chickens and their proteins? Are they denaturate at higher temperatures?

submitted by /u/vstoykov
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There are Langrangian Points in the Sun-Earth system. Are there L-points in Milky Way-Sun system?

Posted: 24 Jul 2016 10:25 AM PDT

And where are they?

submitted by /u/m42ngc1976
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Sunday, July 24, 2016

What is the physical difference in the brain between an objectively intelligent person and an objectively stupid person?

What is the physical difference in the brain between an objectively intelligent person and an objectively stupid person?

What is the physical difference in the brain between an objectively intelligent person and an objectively stupid person?

Posted: 24 Jul 2016 06:20 AM PDT

Does it have to do with connections of neurons in the brain?

submitted by /u/flaminghotcheetos123
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Why does paper turns transparent when i smear fat/oil over it?

Posted: 24 Jul 2016 06:31 AM PDT

How would our understanding of physics (or more specifically E&M) change if we found a magnetic monopole?

Posted: 23 Jul 2016 11:51 PM PDT

If the moon or a big asteroid were to crash directly into the earth, what would happen to the other side of the earth that didn't receive the impact?

Posted: 24 Jul 2016 06:28 AM PDT

Would people get launched right off the ground or something totally different?

submitted by /u/Cyanide814
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Was the theory of infinitesimals proven true?

Posted: 23 Jul 2016 10:07 PM PDT

I understand that this concept is the building block of calculus, but was it simply an "almost true" concept used to understand calculus, or did it become a fundamental truth because of calculus? I could also be framing this question in a horrendously incorrect fashion, because I have only elementary mathematical education.

submitted by /u/taehyun778
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If visible light is photons, then is all electromagnetic radiation photons? If so, why does its wavelength give the photons certain properties (e.x. harmful to humans, visible, can pass through matter)?

Posted: 23 Jul 2016 07:15 PM PDT

Are there any indications that there are elements beyond the 118 we have currently discovered or synthesized? If so, is there any indication that there is a finite number of elements, other than their increasingly short halflives?

Posted: 23 Jul 2016 03:06 PM PDT

As a layperson, I would assume that one could just continually add more protons and neutrons to continually make new elements, but I'm not sure about the physics or any limitations related to that. If I'm right, then I assume the only difficulty is stabilizing the samples long enough for a confirmation, as I know that the last few elements we synthesized had incredibly short halflives. Are there any OTHER limitations to the atomic number of an atom? Will the periodic table ever be done? And are there any ways to forcefully stabilize atoms that would allow us to push farther?

submitted by /u/nathanpaulyoung
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How holes and electrons in the diode gets back to their original position when it is turned off?

Posted: 23 Jul 2016 08:56 PM PDT

When diode is turned on the holes and electrons gets mixed that is the holes will also appear largely on the n side and electrons also appears on the p side but when turned off how electrons and holes get separated as p and n side with same as when it is not connected. Practicals explanation please

submitted by /u/Balaeraivan
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[Physics] How is the sound of moving water created? Do different liquids have specific different "wet" sounds? What factors determine how do they sound like?

Posted: 24 Jul 2016 05:33 AM PDT

Imagine a largish pool of water (or some other liquid) which is still and you submerge your palm in it and slosh it around a bit, making that wet noise. What exactly is making that?

submitted by /u/Fun1k
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Are we--and all multicellular life--just giant biological synergies between our cells?

Posted: 24 Jul 2016 01:22 AM PDT

I mean, there isn't really anything that makes our cells any more special than bacteria, as far as I'm aware. Is it possible that complex life just originated from a few cells suddenly finding out that it is easier to reproduce when attached to different cells?

Edit: not even sure that synergy is the exact phrase I'm looking for, just couldn't be bothered to search for the right one.

submitted by /u/NitzanLeo
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Why is sustained attention span limited to about 20 minutes?

Posted: 23 Jul 2016 01:15 PM PDT

I've noticed it myself as well that it's so much harder to increase how long one can maintain peak concentration than to increase the intensity of said concentration.

What happens at 20 minutes that most adults are limited to a 20 minute sustained attention span?

submitted by /u/Josent
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What the smallest movement that the human eye can detect? Could a human eye perceive 1.5 arc seconds of movement under ideal conditions? What could it detect?

Posted: 23 Jul 2016 01:30 PM PDT

I'm curious about the question of parallax in nearby stars. The parallax of the nearest visible star is 0.77 arc second. That means that every six months or so Alpha Centauri moves twice that (1.54 arc second) accross the sky relative to other stars close to it in the sky.

An arc second is one part in 3600 of one degree. That seems really small. Six months is a long time. I don't know what "ideal" conditions for detecting movement are but I presume the time units are smaller than months.

If I place two LEDs a meter apart and stand a kilometer away, moving one far enough to make a degree of movement across my field of vision means moving it 17m. That feels like it would be possible to detect - we can easily see a semi at that distance.

Moving the LED enough to make 1.5 arc seconds of movement accross my field of view means moving it 7.5mm ((1.54*2*pi*1000m)/(360*3600)) that seems too small to detect.

submitted by /u/bunabhucan
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How does a spider retract its web?

Posted: 23 Jul 2016 02:12 PM PDT

When a spiders retracts or climbs up a strand of its web. What happens to the web?
Does it climb up its web and digest the web?
Does it spool itself up with web?

What happens? Can't find anything that answers this clearly on the web (heh).

submitted by /u/iasmatt
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Is it possible for there to be tiny (let's say basketball sized) Suns or even tiny solar systems in the universe?

Posted: 23 Jul 2016 06:41 PM PDT

I know they wouldn't be observable, so there's no definitive "yes there is" answer, but is there any reason there couldn't be a basketball sized sun? Perhaps even briefly (compared to larger Suns)? Based on current understanding.

submitted by /u/TurangaLeelaFry
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Why are the pressure and volume of a gas inversely related while either one of their relationships with temperature is linear?

Posted: 24 Jul 2016 06:09 AM PDT

Also a related question: It seems like when the number of moles of a gas changes but both pressure and volume are not restricted, the pressure and volume will both change at the same rate. Is this correct? If so, is there an intuitive explanation for why this is the case?

submitted by /u/throwaway146587
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Is there a way to accurately measure amounts of endorphins in the human brain?

Posted: 24 Jul 2016 05:36 AM PDT

Is there a way to accurately measure and quantify specific amounts of endorphins that are released in the human brain? Specifically, I am woundering about endorphins that are released from a painful or traumatic experiences, if that helps narrow anything down. I know one way to do this would be to use a PET machine, but are there other more accurate ways to measure this type of thing?

submitted by /u/thewiscojoker
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What variables produce colorful sunsets? Are beautiful sunsets predictable?

Posted: 24 Jul 2016 05:29 AM PDT

What variables produce colorful, dramatic sunsets? Are beautiful sunsets predictable the way rain or storms are?

We seem to get nice ones after rain. Why is that?

submitted by /u/Mens_provida_Reguli
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What's the fastest growing tissue in the human body?

Posted: 24 Jul 2016 05:23 AM PDT

Does boiling water by lowering atmospheric pressure sanitize water?

Posted: 23 Jul 2016 01:56 PM PDT

We all know that you can sanitize water by adding heat and boiling it. Does the same ring true if the boiling it caused by a lowered atmospheric pressure?

submitted by /u/Whatever1234567891
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Why are sympathetic chain ganglion (and associated nervous tissue) on the outside of the vertebrae, why don't they get the protection that the CNS gets?

Posted: 24 Jul 2016 04:11 AM PDT

Why did they evolve this way? How are they protected?

submitted by /u/chazwazer69
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How did the pressure of earth's atmosphere during past eras compare to that of today?

Posted: 24 Jul 2016 12:21 AM PDT

A friend and I were wondering why aquatic mammals can grow so big, which led to the same question for dinosaurs. I had heard that ancient atmospheres were denser than our current atmosphere, but this seems to be something of a myth. Can anyone shed some light on how the earth's atmospheric pressure has changed over time?

submitted by /u/Versepelles
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How do scientists statistically prove cause and effect?

Posted: 24 Jul 2016 02:56 AM PDT

Is there some formula that proves all confounding variables are irrelevant and one particular direct variation between two variables proves cause and effect? If there isn't some clearly defined line, how much is "good enough" to claim cause and effect?

submitted by /u/CallMeAladdin
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Would I float in wet cement?

Posted: 24 Jul 2016 02:25 AM PDT

Just trying to settle a debate I'm having at 4am. Roommate's convinced you'd sink to the bottom and can't swim/float up.

submitted by /u/anonymousbear
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Saturday, July 23, 2016

Does the craving of different foods at different times have to do with what nutrients your body is currently in need of (protein vs carbs for example)?

Does the craving of different foods at different times have to do with what nutrients your body is currently in need of (protein vs carbs for example)?

Does the craving of different foods at different times have to do with what nutrients your body is currently in need of (protein vs carbs for example)?

Posted: 22 Jul 2016 12:21 PM PDT

How do scientists achieve extremely low temperatures?

Posted: 23 Jul 2016 07:10 AM PDT

From my understanding, refrigeration works by having a special gas inside a pipe that gets compressed, so when it's compressed it heats up, and while it's compressed it's cooled down, so that when it expands again it will become colder than it was originally.
Is this correct?

How are extremely low temperatures achieved then? By simply using a larger amount of gas, better conductors and insulators?

submitted by /u/2Punx2Furious
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How do we know the approximate temperature of distant objects, like planets and stars, as well as from a very long time ago?

Posted: 23 Jul 2016 07:32 AM PDT

I was looking at this very interesting infographic about temperatures in the universe, and it listed objects such as the Boomerang nebula - which is 5000 light years away - as well as the universe at 10-35 seconds old. How can scientists calculate the temperature of stars and nebulae from so far away, and how can they calculate the temperature of the universe from so long ago?

submitted by /u/plasmapuadenas
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At what temperature do muscles operate optimally, and why?

Posted: 23 Jul 2016 01:32 AM PDT

Why does sugary drinks heat faster than simple water in a microwave oven?

Posted: 23 Jul 2016 07:20 AM PDT

For every action, there is an equal and opposite reaction. The universe is still expanding from the Big Bang, is it fair to say that it will some day contract and return to a homogeneous state with little to no empty space?

Posted: 23 Jul 2016 07:02 AM PDT

Title says it all, but is it too expanded to return to its original state?

Thanks!

submitted by /u/bleachworthy
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How dense must a cloud be to completely obscure vision? What is the ratio of ppm to distance light travels through the cloud.

Posted: 22 Jul 2016 12:09 PM PDT

This is a smaller part of a larger hypothetical question I am trying to work through. There is a lead box that is missing one of its six sides buried underground. The open face of the box is the part that is deepest underground. Superman can look through anything that is not lead.

Superman would logically fly partially around the earth until he had an oblique enough angle to peer straight through the earth and see the open underside of the box to determine what is inside.

Here is the question. How much of the earths crust would need to be in supermans way before he could NOT see through it because the cumulative number of lead particles he is trying to look through is too much, the way that normal humans can see through a little bit of water vapor but cannot see through a large cloud Once I have an algorithm for (X) ppm multiplied by (X) distance I can plug it into the numbers I pulled from geological survey papers.

Top soil in the US has an average of 10 ppm of lead and a range of 7 to 20 ppm The Crust has an average of 15 ppm with a range of 1 to 30 The Mantle has a mere 0.185 ppm

After I have figured out the appropriate distance through the earth I am going to have to figure out some geometry for how deep the box must be buried.

This Cloud problem has really derailed me. Any help you can offer would be greatly appreciated.

submitted by /u/atlasonholiday
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If moving electrons produce changing electric field, and if changing electric field produces magnetic field, every electron must produce an electromagnetic wave. This means an atom in its natural state must emit light or other waves in electromagnetic spectrum. But why doesn't this happen?

Posted: 22 Jul 2016 10:02 AM PDT

How can the sea level differ between the Atlantic and the Pacific (around Panama) since they are connected by the antarctic ocean?

Posted: 22 Jul 2016 01:03 PM PDT

How long will it be until new maps will need to be made due to the continents moving?

Posted: 23 Jul 2016 12:28 AM PDT

Carbon Trust: 'A photocopier left on overnight uses enough energy to produce over 1500 copies'. Am I missing something or is this utter rubbish?

Posted: 22 Jul 2016 12:50 PM PDT

All over my workplace there are the bog-standard 'reduce energy expenditure' posters, fairly standard these days. I was having a fairly slow day today and noticed one from the Carbon Trust that states 'A photocopier left on overnight uses enough energy to produce over 1500 copies'.

"That sounds utterly ridiculous" I thought to myself, so I decided to look into it. This is the example they give:

This fact is based on a mid-volume copier. In "sleep" mode this uses 51W and is on all day. Assume

that the office is empty from 6pm to 8am = 14 hours.

Then (51W x 14 hours) / 1000 = 0.714kWh

In copy mode the machine uses 614W and produces 25 copies a minute (1/60=0.016667 hours).

This is (614 x 0.016667) / 1000 = 0.010233kWh for 25 copies

0.714kWh / 0.010233 = 69.77199

69.7719 x 25(copies) = 1,744 copies could be produced overnight.

This doesn't look remotely right to me... So I looked up the specs of our office copier (Ricoh, can't remember the model) and ran my own calculations:

  • Power consumption: 1.6kW
  • Sleep: 0.00088kW
  • Warmup time: 55s
  • Copy time: 6.7s

Core hours for our office are 9am-5pm, this means 16 hours 'idle' time 5pm - 6am (note this is 2h longer than in their example!).

16h * 0.00088W = 0.01408kWh consumed overnight.

The amount of copies produced in an hour for a continuous print job = (3600s - 55s) / 6.7s = 529 copies.

In full operation the copier consumes 1.6kW, and therefore:

1.6kWh / 529 copies = 0.003024kWh/copy

With the energy consumed overnight while 'idle' and the 'energy per copy' I can therefore work out that the actual number of copies that can be produced with the energy wasted overnight is in fact:

0.01408kWh / 0.003024kWh/copy = 4.656 copies

A little less than the 1700 copies they quote!

Have I done something horrendously wrong here, are they using outdated information or is this simply a campaign of misinformation? At best I figure they must have missed a decimal point in their sleep power usage... which would put their number at a more reasonable 17 copies...

Everywhere you look online regarding energy saving in the office this value is quoted, and I simply can't wrap my head around where they obtained these values from.

EDIT: Uhh I don't know if that's the most appropriate flair but I try :|

submitted by /u/Nebbo_67
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What does the airport security swab thing do and how does it work?

Posted: 22 Jul 2016 03:46 PM PDT

Just going through an airport now and was wondering what the swab thing does? The patch of white attached to a handle that they swab over your hands with. What exactly is it?

edit: flaired "chemistry" but honestly I have no idea.

submitted by /u/ricekurt
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[Engineering] If "fast charging" works by increasing amperage, then why can't we just keep increasing amperage to have a super fast charging device?

Posted: 22 Jul 2016 04:30 PM PDT

The title sums it up mostly.

iPhones draw 1A when charging. iPads I believe draw 2.1A because they have bigger batteries. My Nexus 6P draws 3A and thus charges much faster than an iPhone. So why can't we just make a phone that draws, say 10A and charge in minutes?

submitted by /u/MonkeysInABarrel
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Couldn't the same technology in a double-walled, vacuum-sealed bottle (like a Stanley or Yeti) be used for buildings, allowing for super efficient heating and cooling?

Posted: 22 Jul 2016 01:28 PM PDT

I feel this could work, with the right ventilation system. Are there reasons it wouldn't? Or does this already exist?

submitted by /u/JoeKnowsNothing
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Do Microwaves (The appliance) "heat up" or are they instantly as hot as they get?

Posted: 22 Jul 2016 04:06 PM PDT

Would a Microwave be hotter or more powerful 5 minutes into cooking or is it the same from the beginning?

submitted by /u/r3volc
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How much does an individual's DNA change over a lifetime?

Posted: 22 Jul 2016 10:14 AM PDT

All cells divide, except neurons. Each mitosis division requires error prone DNA replication, which in turn causes mutations. Considering things like shortening telomeres, UV radiation, and cancer, there are a lot of opportunities for an individual's DNA to change. How much does it change over a lifetime?

submitted by /u/BoogieBear21
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Does Cholesterol in cellular membrane possess any glycerol structure?

Posted: 22 Jul 2016 08:48 PM PDT

Is cholesterol composed of glycerol?

submitted by /u/credditational
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Are flies more attracted to different colours than others?

Posted: 22 Jul 2016 11:00 AM PDT

TL;DR Do flies prefer to hang around certain colours? Why?

So me and my father are camping in Lappland, Sweden and we have been eating our meals out in the wild by our tent. He has been eating and drinking in peace while I have been in a war with the flies. They all seem to LOVE my pink camping mug, and gather around it in groups while my father's mug have not had a single fly land on it. His mug is dark green.

Is it because flies see my mug better in this environment, or is it because flies, just like me, love a little colourful touch to their daily lives?

Answers with any kind of information is greatly appreciated so that my father and I can end our own speculations.

EDIT: By following the link you will see a picture of my father's mug versus my mug. http://m.imgur.com/h3MV3We,h8xCoVb http://imgur.com/Bik0UGa

submitted by /u/Glooten21
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At very high gravities are thermobaric properties asymmetrical?

Posted: 22 Jul 2016 06:13 PM PDT

By the gods if I had the maths to avoid that word salad I would use it.
I assume brownian motion for thermobaric forces, but far inside a gravity well, wouldn't the forces distribute quite differently?

submitted by /u/FondOfDrinknIndustry
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Does Vitamix blending kills probiotics, enzymes or damages chlorophyll in raw whole plant foods?

Posted: 22 Jul 2016 08:10 AM PDT

I am wondering about damage on cell level that Vitamix may be causing while blending plant based foods. E.g. if I blend kombucha, spinach, or an apple -- will it kill probiotics in kombucha, damage chlorophyll in spinach, or kill enzymes in the apple?

Thanks so much! I can't wait to read what you post. :)

submitted by /u/MssDee
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How do we know that vaccines work and are responsible for protecting against certain diseases?

Posted: 22 Jul 2016 12:14 PM PDT

Anti-vaxxers always state there are no double blind randomized controlled trials. If that is true, then how do we know for sure that the vaccines are helping to protect against certain disease?

submitted by /u/WiseShepherd
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