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Sunday, May 26, 2019

What is the point of correlation studies if correlation does not equal causation?

What is the point of correlation studies if correlation does not equal causation?


What is the point of correlation studies if correlation does not equal causation?

Posted: 26 May 2019 03:28 AM PDT

It seems that every time there is a study posted on reddit with something to the effect of "new study has found that children who are read to by their parents once daily show fewer signs of ADHD." And then the top comment is always something to the effect of "well its probably more likely that parents are more willing to sit down and read to kids who have longer attention spans to do so in the first place."

And then there are those websites that show funny correlations like how a rise in TV sales in a city also came with a rise in deaths, so we should just ban TVs to save lives.

So why are these studies important/relevant?

submitted by /u/hrrm
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Does illness affect the phases of sleep in a person's sleep cycle?

Posted: 25 May 2019 07:32 AM PDT

I know that in Stage 3 of NREM sleep, the body works to physically restore itself by releasing HGH, etc., and I know that the longer someone sleeps for, the amount of time spent in the NREM phases decreases and the amount of time in the REM phase increases.

I am wondering if someone who is seriously ill (or recovering from a serious illness) might experience an alteration of the regular sleep cycle--namely, would they be spending more time in Stage 3 in order to "repair"? Or would their sleep phases occur as they would for any healthy person?

Edited to add: As this post gains attention I felt I should say that it's generally understood/has been experienced that illness results in poor sleep. Mainly I'm looking for information about how the individual stages of sleep may be affected by illness and in particular if periods of NREM 3 might be extended for longer than they normally would be. Thank you for all of the great answers so far!

submitted by /u/YoungRL
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Is there a measurement scale for stickiness?

Posted: 25 May 2019 04:06 PM PDT

Can simple invertebrates like snails feel pain? How can we know for sure either way?

Posted: 25 May 2019 03:22 PM PDT

Why do high energy particles like Gamma Rays or Cosmic Rays damage our DNA? How exactly do they damage it?

Posted: 25 May 2019 05:42 PM PDT

What makes these particles more harmful than say infrared light?

submitted by /u/theinquisitor7777
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What was the cost of producing plastic back in the 1950's?

Posted: 26 May 2019 07:45 AM PDT

Why do some digital clocks lose or gain time? My coffee maker has to be readjusted every couple months to fix the time. Used to have a car that would gain a few minutes each month.

Posted: 26 May 2019 07:07 AM PDT

How do certain foods and drinks increase or decrease blood pressure?

Posted: 26 May 2019 06:53 AM PDT

When I google I only get lists of foods which are purported to raise or lower blood pressure, but no explanation of the mechanisms.

submitted by /u/EndOnAnyRoll
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What impact does living in the tropics that are dry, dusty, and windy have on our lungs? Specifically, in terms of high density of particles in the air. Thanks in advance.

Posted: 26 May 2019 06:06 AM PDT

Organ donation: is there a "shelf" life of how long an organ could "live"?

Posted: 25 May 2019 03:23 PM PDT

I might have titled the post poorly but my curiosity is on one question: theoretically, is it possible for an organ to "live" forever if it keeps being donated and transplanted? For example, a donated heart is transplanted to person A who then donated the heart to be transplanted to person B after person A dies. Would the heart be able to live forever?

submitted by /u/alfxy
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After seeing several high definition photos of moons and planets, there is a large amount of visible craters. If the earth was devoid of all life, would earth's surface show just as many craters?

Posted: 26 May 2019 01:51 AM PDT

On a cellular level, what causes us to grow and age?

Posted: 25 May 2019 05:29 AM PDT

is there any evidence of two stars colliding?

Posted: 25 May 2019 11:49 PM PDT

How does game theory/environmental stable strategies lead to mix strategy behaviors being optimal ?

Posted: 25 May 2019 07:54 PM PDT

I understand the difference between tactics in strategies in terms of reproductive success for each type of behavior, but I am failing to understand why in some ( I'm not sure if it is all) the optimal outcome for the group is to have mixed strategies. Can some please explain to me how that is possible? (If I am wrong anywhere any corrections would be great)

submitted by /u/TM06-Toplanner
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Would the atoms change weight on different planets/Stars?

Posted: 25 May 2019 11:38 PM PDT

I remember that the different gravities create different weights so would it be the same with atoms?

submitted by /u/lawer12346
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How does the composition of milk change when it turns sour?

Posted: 25 May 2019 10:01 AM PDT

When a positive event occurs at the same time as a negative event, what determines whether a positive association or a negative association is built?

Posted: 25 May 2019 10:39 AM PDT

I came across this question as I'm planning for a move and trying to get my cat used to the carrier as I'll be driving for multiple hours a day. I've been putting his favorite blanket in the carrier, feeding him treats when he goes in, and petting him as he goes in to create a positive association with the carrier.

This got me thinking, what determines that a positive association will be built to the carrier from all those techniques and not a negative association to all of those techniques from the carrier? Another example would be treats after medicine: does the cat create a positive association to the medicine from the treats or a negative association to the treats from the medicine? Also, how does this apply to humans?

submitted by /u/Benvoliolio
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During fission/chain reactions, how do atoms absorb neutrons??

Posted: 25 May 2019 09:04 AM PDT

How do neutrons "Go past" the electron cloud and into the main nucleus itself?

submitted by /u/J-100
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Why is pi irrational when it can be formed by using an infinite series of fractions?

Posted: 25 May 2019 05:16 AM PDT

Does the distance of electron orbitals from the nucleus change as more nucleons are added?

Posted: 25 May 2019 06:57 PM PDT

Will a vacuum on the bottom of the ocean float?

Posted: 25 May 2019 06:53 PM PDT

If you would place a lightweighted box with a vacuum inside on the ocean floor what would happen? Will it stay on the bottom because of the pressure on top of the box or wil it float because the density inside is lower then the water?

submitted by /u/blaze519
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Do I weigh more after I fart?

Posted: 25 May 2019 06:38 PM PDT

How do medical scientists gather people/a person for a study?

Posted: 25 May 2019 09:38 AM PDT

Obviously, nobody can be everywhere at once - there might be a person with the exact condition a neurologist is trying to study on the other side of the country, and they have no idea that they're there.

So outside of general practitioners passing on referrals until someone eventually goes "oh hey, this is actually really rare, can I study it more in depth?", how do researchers gather relevant people for a group study/find that one specific person that has that specific combination of traits/conditions?

submitted by /u/Portalboat
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Saturday, May 25, 2019

Historically, why did fevers used to kill so many people, but now they're a rarely fatal annoying symptom?

Historically, why did fevers used to kill so many people, but now they're a rarely fatal annoying symptom?


Historically, why did fevers used to kill so many people, but now they're a rarely fatal annoying symptom?

Posted: 24 May 2019 12:37 PM PDT

Why does fruit bruise?

Posted: 24 May 2019 05:52 PM PDT

How would soft drinks (Carbonated) behave in space?

Posted: 24 May 2019 10:56 AM PDT

I was watching a video the other day about how an astronaut invented a special drinking cup for liquids in space, and that gave me a question that lingered in my brain enough to ask here.

Basically, how do soft drinks, like Coke and Pepsi, act in space where there's no gravity? How do the bubbles form and where do they go? Does it pose any dangers? If left opened to the "air" in the space-station, would it become de-carbonated like here on Earth? or will it hold onto the gas in it..etc

(I wasn't sure if I should use Astronomy, Physics or Chemistry for this, sorry if I made the wrong call.)

submitted by /u/AidenR0
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Why do estrogen levels drop before ovulation and then rise again after?

Posted: 24 May 2019 02:42 PM PDT

What is the purpose of the dip; why doesn't estrogen just stay elevated?

submitted by /u/la_petitemort
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Are Hurricanes/Tornadoes - Net Heating or Net Cooling events or Heat Neutral?

Posted: 24 May 2019 12:51 PM PDT

I know these events are caused by cold fronts and warm front meeting.

All said and done though are the individual events Net Warming Net Cooling or does it just help distribute the same temperature move evenly?

Do the storms themselves help alleviate environmental warming or contribute to it?

submitted by /u/ZebraHunterz
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How does wood become driftwood and why does some wood just rot in water?

Posted: 24 May 2019 01:11 PM PDT

How does it form, and why does not all water logged wood become drift wood?

submitted by /u/pancakelife
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Does a big molecule experience Buoyancy?

Posted: 24 May 2019 12:33 PM PDT

I am wondering how big an object has to be to be affected by Buoyancy. Atoms cannot be big enough, right? But big molecules maybe?

I mean, it is difficult to speak of "mass per volume" for a single molecule. And if certain big molecules are affected by Buoyancy they would probably form layers at certain depths. I do not think that is the case. So how big does the object have to be? The size of a few water molecules? Is there an equation for this limit?

submitted by /u/neuromat0n
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Why doesn't an atoms atomic number correlate with how common the element is?

Posted: 24 May 2019 10:25 AM PDT

Hydrogen has the atomic number 1, and it's also the most common element in the universe. Helium has the atomic number 2 and is the second most common element.

However, after that, the atomic number doesn't correlate to the elements abundance. The next most abundant is Oxygen, which has an atomic number of 8, then Carbon with an atomic number of 6.

This seems really weird to me because from my understanding, when fusion happens, for oxygen to be created, it has to first become lithium, beryllium.... etc, until oxygen. I'm guessing this is where I'm making my mistake and my understanding of fusion is not correct.

submitted by /u/Whateveritwantstobe
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What percentage of people sign petitions?

Posted: 24 May 2019 12:27 PM PDT

So for instance if a petition got 100000 signatures how many people would actually share those views. I was wondering this because of the revoke Brexit petition which got 6 million signatures although something like 48% (about 30 million) don't want Brexit.

submitted by /u/Boop121314
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When ignited what temperature does gunpowder reach?

Posted: 24 May 2019 12:04 PM PDT

The various sources I've found provide conflicting information, and I'd genuinely like to know the truth of the matter.

Also, on a slightly related note, what would be the 'blast radius' of a barrel of gunpowder being detonated? How about the blast radius of 10 square feet worth of it?

submitted by /u/VelaNovaMan
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If I take the rubber piece of a capacitive stylus off of the pen from which is came, and place it on an arbitrary stick or non-stylus pen, it loses its capacitive functions. What, besides the rubber, allows a capacitive stylus to function?

Posted: 24 May 2019 10:39 AM PDT

Would the alignment of a magnetic compass needle be affected during a thunderstorm?

Posted: 24 May 2019 09:26 AM PDT

We know that that compass needle changes its alignment when a wire with electricity running through it is brought closer to the needle. So will the same thing happen when there would be lightning strike nearby?

submitted by /u/whitehairdude
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Is there any data/science showing pornography actually "damages" a post-pubescent person's psyche?

Posted: 24 May 2019 08:51 AM PDT

With Theresa May's resignation I saw some redditors posting about her law that UK citizens require ID to access porn sites, to prove they're 18+.

So it made me wonder, is there any actual science showing "damage" (whatever that would mean in this context) as a result of young consumption of pornography?

I am talking about post-pubescent specifically here but younger ages would be interesting as well.

submitted by /u/Dynamaxion
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What does the bend at the end of a plane's wings do?

Posted: 24 May 2019 06:09 AM PDT

What is the mechanism for catch-up growth in children?

Posted: 24 May 2019 10:58 AM PDT

For example, how can a malnourished child 'catch-up' and regain their lost growth once fed properly, why can they make up for this lost time ? I realise this is phrased poorly but any information would be great.

submitted by /u/utf76
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Why does catnip contain nepetalactone? Wouldn't that be detrimental to the plant?

Posted: 24 May 2019 02:31 PM PDT

Catnip contains nepetalactone, which is a feline attractant and causes cats in the area to bite and crush the plant. Why did catnip evolve to produce this chemical? Is there some other advantage of nepetalactone that outweighs the negative effects of its cat-attracting capabilities?

submitted by /u/Golden_Lambda
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Friday, May 24, 2019

What do heavy metals really do to a person, and what does our body do to get rid of them?

What do heavy metals really do to a person, and what does our body do to get rid of them?


What do heavy metals really do to a person, and what does our body do to get rid of them?

Posted: 23 May 2019 11:02 PM PDT

There's been plenty of misinformation spread thanks to the vaccine scare, so I'm curious to have some facts.

Let's say some unfortunate person has eaten a tomato with an amount of lead in or on it.

The symptoms of heavy metal poisoning are easy enough to find online, but what exactly is happening to cause the symptoms? It's usually a bad thing to have them around in the body, so what does the body do to remove them? Are they just filtered out by the kidneys like a lot of other stuff? Do they break down somehow on their own?

submitted by /u/ZeinaTheWicked
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Are neurons immortal? Do neurons die and regenerate like the rest of your cells throughout your life? If so, how is the information preserved?

Posted: 23 May 2019 10:13 PM PDT

A) Are neurons immortal?

B) If not, how come my memory doesnt get wiped every few years or even decades?

C) Also, if a person were to live for a very very long time with the help of machines that would keep his organs working, would we be able to observe all his neurons die and his memories fade? Or would the brain just continue to function indefinitely? (I'm short, can the brain die of old age like other organs)

submitted by /u/mrhouse1101
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How did we discover molecular processes like the Krebs cycle or electron transport chain?

Posted: 24 May 2019 05:09 AM PDT

"I need someone to explain this to me like I'm a 5 year old" - Michael Scott

It's very easy to see how astronomers can look at large moving bodies and formulate a hypothesis and test the hypothesis with models and then identify if celestial motion can be accurately predicted. How do we do this in a cell? How do we replicate cellular biology? It's blowing my mind and I assume these processes work so fast and are so small that we can't visually see them.

submitted by /u/tkcalibo
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Why does anemia make you crave chewing ice?

Posted: 23 May 2019 09:30 PM PDT

Does a binary star system create a dynamic Goldilocks zone?

Posted: 23 May 2019 11:09 PM PDT

Would 2 or more stars in a system create a habitable zone which is always changing in position in respect to the stars' location?

submitted by /u/KOSTAFLEX
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Why do left - handed fermions form a doublet/transform under SU(2) and right handed don't?

Posted: 24 May 2019 06:08 AM PDT

I am studying the electroweak interaction and Higgs - mechanism and I am trying for days now to find an answer to my questions but I can't... I would be glad for help :)

submitted by /u/herrschoftszeitn
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Does grass have flowers?

Posted: 24 May 2019 05:37 AM PDT

I was wondering, if grass has flowers or how are they producing seeds you can buy and make your lawn. I have never seen that type of grass having flowers although the seeds look similar to grain seeds.

submitted by /u/PelicanRulezz
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How is the maximum capacity of a bridge calculated?

Posted: 24 May 2019 03:48 AM PDT

Maximum amount of cars that can be on a bridge, taking in count the length and the weight of the car and the outside factors

submitted by /u/killthots
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Is a Reynold's number higher than 4000(using SI units) always turbulent? Also where does the usefulness of this value break down?

Posted: 23 May 2019 11:44 PM PDT

It seems to me like Reynold's number is one of those "good enough" types of equations and I've been wondering if this relation is always true or if certain cases defy any assumptions made by the usual equation of (density X velocity X diameter)/(dynamic viscosity)

submitted by /u/Gallade475
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When a person is anesthetized, does s/he behaves as if were assleep (like snoring, dreaming) or is it something completely different?

Posted: 24 May 2019 05:41 AM PDT

Basically my brother is in surgery right now and I began to wonder about this.

Thanks in advance

submitted by /u/DangerASA
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Do countries in the tropics have a, "flu season"?

Posted: 23 May 2019 11:42 PM PDT

I live in Australia and we are coming into winter so it's coming to, 'flu season', and time to get our flu shots. What happens in the tropics where it is just warm all the time? Do they still have a flu season or a certain time of year they are encouraged to get flu shots?

submitted by /u/Ruby_Dalia
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Can there be dwarf rogue planets?

Posted: 23 May 2019 11:56 PM PDT

Can there be dwarf rogue planets?

submitted by /u/RABALA
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What do the pollen count numbers actually mean?

Posted: 23 May 2019 08:47 AM PDT

A friend of mine is looking for an explanation of the pollen count scale.

She wants to know "how a measurement is converted to this scale, is it linear, etc." She was looking up information on it, but she kept getting simplified style info, and she wants more detailed scientific explanation of it.

Thank you!

submitted by /u/junipermucius
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How does the equipartition system apply to macroscopic degrees of freedom?

Posted: 24 May 2019 02:02 AM PDT

My lecture notes on Experimental Methods includes a description of thermal/Johnson noise in electrical circuits. The argument used to quantify the amplitude of this noise is to consider a closed RC circuit (no voltage source). The energy stored in the system is (1/2)CV2. Equipartition then requires every quadratic energy term to store an energy (1/2)kT (at high temperatures), and from this we can obtain the RMS voltage.

I fully understand why equipartition applies to a system composed of a large number of particles, where each composing particle introduces as many microscopic quadratic energy terms as it has degrees of freedom. What I don't get is why the voltage of the RC circuit should count as a degree of freedom in itself, given that it is macroscopic.

I suppose this connects to a broader question about the range of applicability of the equipartition theorem. What counts as a "degree of freedom" of a system?

I hope this question is clear - I'm not entirely sure it's clear in my head and so please do ask if I can clarify something.

submitted by /u/Movpasd
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Is it possible to have saltwater rain?

Posted: 23 May 2019 10:22 AM PDT

If what I've read about photons is correct, they follow the conservation of energy. What happens to the energy from the photon after it is absorbed by the retina and we "see" it?

Posted: 23 May 2019 11:26 AM PDT

What, physiologically, makes an animal warm blooded or cold blooded?

Posted: 23 May 2019 11:25 AM PDT

Does heat generation come from the inefficient use of high energy molecules? What parts of the body generate heat, does this happen everywhere, or does it occur in a particular organ such that blood can carry it to other places? I've heard that muscle usage might be attributed to this, however we still generate heat while we are resting, right?

submitted by /u/WhatIsPlagiarism
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Why do OTC drugs like ibuprofen sometimes turn up as false-positives for THC and/or PCP on drug screenings?

Posted: 23 May 2019 12:06 PM PDT

This has happened to me twice, and although it didn't effect the outcome of my employment in anyway (they don't test for THC), it has me wondering how many folks out there may have lost their jobs because of this.

submitted by /u/SoldMomForKarma
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How does possitive void coefficient work?

Posted: 23 May 2019 01:46 PM PDT

Hey, so i understant negative void coefficient; steam = 1/1860 the neutron absorbing qualities of water, more steam bubbles, or voids, = less neutons absorbed = reactivity decreases.

Can someone please explain how positive void coefficient works. i understant that increased voids = increased reactivity, although in not sure why it works. I can grasp this in a RBMK reactor where the moderator (graphite) is different to the coolant (water). This is because the increased voids = less liquid water = less cooling, however the graphite moderator remains there so neutrons absorbed reducing reactivity, although in not sure what relevence the increase of steam from water has on neutrons (apart from the lack of cooling aspect, which effects temp of core however to my knowlage not neutrons).

Appologies for the shoddy explination

I hope you understand what im asking Thanks

submitted by /u/Dat-Boyo
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