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Monday, June 26, 2017

What happens to water when it freezes and can't expand?

What happens to water when it freezes and can't expand?


What happens to water when it freezes and can't expand?

Posted: 26 Jun 2017 04:16 AM PDT

What is the reason for our irrational disgust of insects and arachnids? Were humans often poisoned-killed by them while we evolved?

Posted: 25 Jun 2017 07:54 AM PDT

Why is it recommended to eat a lot of fruit, but it is not recommended to eat a lot non-fruit sweet snacks? Is fructose better than other kinds of sugar?

Posted: 26 Jun 2017 01:22 AM PDT

Is arcing a more efficient way to transfer electricity versus a conductive wire? Ignoring the obvious safety concerns, could we have arc towers instead of power lines?

Posted: 26 Jun 2017 02:13 AM PDT

Why does 100°C water feel so much hotter, more painful, and cause more damage than 177°C air?

Posted: 25 Jun 2017 08:38 PM PDT

For example, submerging your hand in boiling water will cause severe burns, but you can easily put your hand inside a hot oven for much longer than you could in the boiling water.

Also, why does a soft rug at 0°C feel warmer to your bare feet than a concrete floor at the same temperature?

submitted by /u/Sundancelancer
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Does chlorine that settles in to ground when irrigating lawns or draining swimming pools degrade into something else, or remain unchanged?

Posted: 26 Jun 2017 07:13 AM PDT

I work in water utilities. 99% of residents in my city irrigate their lawns with city water, and we like chlorine to be 1.8-2.1 in this city. All run off from irrigation and when people drain pools and the like seeps into their lawn, and all water eventually makes it to the lake system. It's common knowledge here that chlorinated water once "filtered" through ones lawn removes nearly all the of the chlorine from the water by the time it makes its way back into our lake system.

So my questions is, does all that chlorine sit in the ground unchanged? Or does it eventually degrade into something else?

submitted by /u/citizensandwich
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What exactly happens in fission and fusion reactions? and how are fission chain reactions sustained?

Posted: 26 Jun 2017 04:22 AM PDT

I know the basics of fission and fusion with fission being the splitting of the atom and fusion being atoms combining. But as I am only 14 I don't have a major understanding of this topic but I really love physics and learning more so any answers would be greatly appreciated.

Thanks in advance.

submitted by /u/TekkasSlovakia
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How does mercury form amalgams?

Posted: 26 Jun 2017 06:04 AM PDT

I would like to know more about how they are formed and how this compares to other types of bonding but the wikipedia page only says its an alloy but nothing about the process. My chemistry level is only at A-level.

submitted by /u/megamit
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Where does all the chlorine we have in the HCl acid in our stomachs come from?

Posted: 24 Jun 2017 08:58 PM PDT

Why does this problem not intuitively make sense?

Posted: 25 Jun 2017 11:08 PM PDT

So here's a quick question about a fundamental math question I've never truly understood despite being able to work it out... Here it is: Say you have a 100 sided die (yeah, I know it's unrealistic), and you're going to roll this die 'x' amount of times until you roll a 1 (1/100 chance). Now you want to find out how many time you have to roll this to give you a 50% chance of rolling a 1 at any point in those rolls. Well, by doing a little bit of arithmetic, we can find that if you roll that die ~69 times, there's a 50% chance of rolling a 1. My question is what is the logic for this, and why do most people naturally think you'd have to roll it 50 times to get a 50% chance of getting a 1...

We know that's wrong, but why would many intuitively think that is correct? If the question is confusing, please let me know and I'll try to clarify.

submitted by /u/mathnerdm
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If stars in a galaxy increase in velocity the further they are from the center, why do galaxies have spirals? Wouldn't spiral arms indicate slower speeds as you approach the edges of a galaxy?

Posted: 26 Jun 2017 07:27 AM PDT

I understand dark matter plays a role here, keeping the galaxy spinning as one like a dinner plate. Does this indicate the spirals form before enough dark matter appears?

submitted by /u/Kythorne
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If I move both my index fingers at once, am I sending one signal to both hands, or am I sending 2 individual signals? Is there a signal queue?

Posted: 25 Jun 2017 10:11 PM PDT

Do any animals show appreciation for music?

Posted: 25 Jun 2017 05:02 PM PDT

If you were able to cool plutonium to 0 kelvin, would it stop emitting alpha radiation?

Posted: 25 Jun 2017 08:18 PM PDT

We have thousand separator for big numbers (eg: 100,000,000) but why is there no separator for very small decimal numbers?

Posted: 26 Jun 2017 05:52 AM PDT

I never realized how useful separator is for counting money until I met bitcoin. I can easily read thousands or millions of dollar value, but reading how much bitcoin I have is kinda hard. How much again is one satoshi? is it nine zero or ten zero before comma?

then after looking at this satoshi btc converter site I realized that.. why's there no decimal separator like in thousand ?

Edit : sorry if I put the wrong flair, first time asking here.. hehe

submitted by /u/fugogugo
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Is primitive streak/ primitive node linked in any way to coccyx bone?

Posted: 26 Jun 2017 07:52 AM PDT

Hi, I'm debating with muslim student of medicine, and he was telling me about common belief among some muslims that coccyx bone has been described by prophet Muhammad as special in embryo formation and indestructible. He quoted Hans Speman via this article http://www.nicheoftruth.org/pages/the_coccyx_bone.asp

Questions:

1) I assume they are stretching the meaning of primitive streak/node to mean it is the same as coccyx bone, while coccyx is but a product. Could you point to some academic literature that explains why/why not it's a correct assertion?

2) He also claimed coccyx bone doesn't decompose. Is there any truth in it? Is it decomposing slower? Please also point to any literature here.

Thanks

submitted by /u/ScienceThrowAway5423
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Where do river-spawning, migratory fish exist? Are they only in cold climates?

Posted: 26 Jun 2017 07:51 AM PDT

I've been reading about Patagonia's efforts to recover river environments, mostly in the US and Canada by lobbying for decommissioning and destruction of dams that affect fish that swim upriver from the ocean, such as salmon.

I was wondering, do any species like these exist in hotter climates? Such as in Mexico or Brazil? My state in Mexico has 11 rivers and I believe 10 of them are dammed.

Is this an issue only for salmon and these more northern and southern latitudes? Do any tropical species migrate like this?

submitted by /u/CrombopulousMichael
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How was velocity and position measured on a continuing basis in Cassini? What were the reference objects and were there several?

Posted: 26 Jun 2017 06:50 AM PDT

[Engineering] Tempering is known to increase the toughness of steels, but why does it work? How does it operate on a molecular level?

Posted: 26 Jun 2017 12:00 AM PDT

"Tempering is a process of heat treating, which is used to increase the toughness of iron-based alloys." (from wikipedia). I understand that metallurgists use high temperatures to increase the toughness/reduce fracturing. But why do higher temperatures lead to better elastic materials (like springs) and lower temperatures lead to better toughness (like hammers or screwdrivers).

submitted by /u/DoloPingu
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What is the most populous mammal on Earth?

Posted: 26 Jun 2017 05:36 AM PDT

Is it humans? By how much?

submitted by /u/t510385
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Before nuclear fission/fusion was discovered, what did people think powered the sun?

Posted: 25 Jun 2017 10:41 AM PDT

What dinosaur species may have witnessed or been first impacted by the Chicxulub crater?

Posted: 26 Jun 2017 05:26 AM PDT

So I am writing some fiction set at the very end of the Cretaceous and in a lot of Media T-rex and triceratops seem to be looking right at the impact but given that it hit near mexico - what poor species would have witnessed the meteor impact?

submitted by /u/damianlz
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MHD. How do current sheets form?

Posted: 26 Jun 2017 05:16 AM PDT

Currently studying magnetic reconnection and my notes say that even in ideal MHD conditions there are current sheets formed between separate plasma region. I'd like to know process, not reconnection mind you, but the formation of the sheet.

submitted by /u/Michkov
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Why are we told to cover our mouth with a wet cloth when there's a lot of smoke?

Posted: 25 Jun 2017 07:14 PM PDT

Sunday, June 25, 2017

I am cancer researcher Wes Wilson. I study immunotherapies, which use the immune system to treat cancer. AMA!

I am cancer researcher Wes Wilson. I study immunotherapies, which use the immune system to treat cancer. AMA!


I am cancer researcher Wes Wilson. I study immunotherapies, which use the immune system to treat cancer. AMA!

Posted: 24 Jun 2017 08:06 AM PDT

Hi, I'm Wes Wilson (/u/LabcoatNomad), a Canadian cancer researcher currently working in Australia on treating metastatic mesothelioma using combination immunotherapy treatments. I first got started in cancer research in Toronto at Sunnybrook Hospital before moving into research on childhood brain tumours at The Hospital for Sick Children. There I worked on the epigenetics of childhood brain tumour progression in 2010.

In 2013 the journal Science labeled cancer immunotherapy as "the breakthrough of the year" and many cancer patients were given new hope for treatment. But the work and research to identify the best treatments and combinations for the variety of types of cancer is still on going and desperately needed. No one knows why some immunotherapies work for some patients and others they fail. Our work hopes to increase the effectiveness of these new therapies by combining it with adjunct therapies to help the body self-vaccinate against the tumours!

I will be back at 8pm ET to answer your questions. Ask me anything!

(Note from the mods: we cannot comment on specific patients' cases, so please do not post any personal medical information on the subreddit. Thank you!)

submitted by /u/AskScienceModerator
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If left, spilled soda eventually ends up attracting ants. Would diet soda do the same, or do they ignore it because there is no caloric benefit?

Posted: 24 Jun 2017 07:13 PM PDT

Why don't you feel an electric shock while touching a 9V battery but feel one with the fake pen and gum toys with button cells?

Posted: 25 Jun 2017 04:02 AM PDT

Is atomic stability of radioactive elements affected when they form a molecule with another element?

Posted: 25 Jun 2017 02:09 AM PDT

For instance say plutonium bonds with some other element. Is it's half life reduced or is it constant regardless?

submitted by /u/Largedump
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Does Jupiter have a solid core of anything or is it truly just a large ball of gas?

Posted: 24 Jun 2017 05:25 PM PDT

Why do fishes go belly up?

Posted: 24 Jun 2017 07:26 PM PDT

When a fish dies, why do the go upside down?

submitted by /u/Jettward
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Would Earth's magnetic field get weaker as the outer core solidifies?

Posted: 24 Jun 2017 09:07 PM PDT

How does staying hydrated help your body fight infections? Is it a matter of just not being dehydrated?

Posted: 24 Jun 2017 03:44 PM PDT

Is it possible to burn calories without increasing the heart rate? Also, why does resting heart rate tend to go down the more "in shape" someone gets?

Posted: 24 Jun 2017 03:45 PM PDT

How does sunscreen work?

Posted: 24 Jun 2017 03:34 PM PDT

Two photons are fired to the same point at the same time from different distances, so one photon reaches the destination first, yet for both of the photons no relative time has passed, yet one arrived first. What did the photon which was more distant "see"?

Posted: 25 Jun 2017 03:54 AM PDT

The question still stands for if the photon that was closer would be fired later, yet arrive first.

submitted by /u/uniklas
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Does electrolysis happen when a current passes through the body?

Posted: 24 Jun 2017 09:54 AM PDT

I was thinking that areas of the body with salt and water (a saline solution) should cause electrolysis to happen, making NaOH on/in the body and releasing chlorine gas. However, when I get a current through my body from un-grounded electronics (like my macbook), I don't feel or smell any sodium hydroxide or clorine gas. Why is this? I would really expect NaOH in the eyes to sting.

submitted by /u/Annrothb
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Would sending a Nanobot spacecraft through a black hole using Quantum Communication be the best method for gathering information?

Posted: 24 Jun 2017 07:13 PM PDT

Since you probably wouldn't be able to use radio / light communication once you went past the event horizon.

submitted by /u/HeavierMetal89
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Why ∞ x 0 is a indetermination and not 0?

Posted: 24 Jun 2017 11:41 AM PDT

How does Missile Approach Warning (MAW) systems work?

Posted: 24 Jun 2017 12:21 PM PDT

As title. Detecting a piece of metal flying so fast and knowing where it targets seems to be quite an amazing feat.

submitted by /u/gordandisto
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Why, in a fluid, is pressure the same in all directions?

Posted: 24 Jun 2017 11:26 AM PDT

I understand that, with depth, the weight of the fluid in question increases, so that accounts for the downward force, but why do fluid particles exert the same pressure from every other direction?

submitted by /u/samtheman0126
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How much energy would be released from a single atom splitting?

Posted: 24 Jun 2017 04:03 PM PDT

Also, how many atoms were split during the explosions of little boy and fat man? What about the tsar bomb?

Thanks in advance

submitted by /u/Inferno_4
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Saturday, June 24, 2017

Do insects/arachnids get headaches?

Do insects/arachnids get headaches?


Do insects/arachnids get headaches?

Posted: 24 Jun 2017 05:21 AM PDT

How do brain cells get replaced without changing who you are?

Posted: 24 Jun 2017 04:49 AM PDT

I don't have any cells that I did from 8 years ago so how id that possible?

submitted by /u/1-9-9-8
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What makes electronic money officially money? Why can't people forge electronic money?

Posted: 23 Jun 2017 04:53 PM PDT

Did humans always have to drink water regularly or was it an environmental/genetic factor that caused it?

Posted: 24 Jun 2017 05:42 AM PDT

When my garden soil is too alkaline, I'm told to add sulphur or other somewhat noxious chemicals. Why can't I just pour a bottle of vinegar into the garden bed?

Posted: 24 Jun 2017 03:35 AM PDT

What would go wrong?

submitted by /u/SurprisedPotato
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What's the reason diesel engines are left to idle for long periods of time instead of shutting them down?

Posted: 24 Jun 2017 06:44 AM PDT

Heavy diesel engines (buses, construction equipment, transport trucks, etc) particularly tend to be left idling for long periods of time between uses. What's the rationale behind this practice?
Is this practice still applicable to modern engine design?

submitted by /u/TerribleTortoise
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Why does a lump form when a mosquito bites you, and why does it grow as you scratch it?

Posted: 23 Jun 2017 08:54 PM PDT

Have we put life on Mars?

Posted: 23 Jun 2017 02:44 PM PDT

Unless the rovers that we sent to Mars were 100% Sterilized before they were launched, wouldn't they have carried with them lots of microorganisms, even ones that could eventually evolve into more advanced life forms?

submitted by /u/isademigod
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Do animals acclimatise to heat in the same way humans do?

Posted: 24 Jun 2017 02:09 AM PDT

I understand that the human body acclimatises to heat over a period of time, but do animals such as dogs and horses undergo the same changes? If I take my dog to a hot country, will his body make the same physical changes as mine in response to the change in climate?

submitted by /u/Hillshurt
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Why is it that most animals have hair that stops growing at a certain point, but human hair does not?

Posted: 23 Jun 2017 03:09 PM PDT

Is it possible to alter the epigenetic structure of a zygote?

Posted: 24 Jun 2017 02:17 AM PDT

Why does humans lose their hair when undergoing chemo, but dogs don't?

Posted: 24 Jun 2017 04:10 AM PDT

Inspired by a post over at /r/rarepuppers, which got me thinking...

submitted by /u/TrinitronCRT
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Why do cleaning bottles say, "Kills 99.9 percent of germs"? What about the other 0.1 percent and why is it immune?

Posted: 23 Jun 2017 04:40 PM PDT

Is there a differential equation relating a change in thrust with a change in the semi-major/semi-minor axes?

Posted: 23 Jun 2017 08:41 PM PDT

I have played around a bit, and I feel as though I have an expression that does what I want. However, I can't check it. Is there a established equation for da/dT?

submitted by /u/makeshift8
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Would LIGO signal change for merger of larger black holes?

Posted: 23 Jun 2017 04:56 PM PDT

Would the signal picked up by LIGO from the merger of two moderately large black holes (1,000 suns each to pick a number) be the same only larger, or would it convey additional information not obtained by the signals so far?

submitted by /u/bjscript
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Aquariums hold sea life that live great distances below the surface where the pressure is much greater. Do aquariums some how simulate the amount of pressure the animals would experience in their natural habitat, or does it not matter?

Posted: 23 Jun 2017 02:47 PM PDT

How much does CO2 from carbonated beverages contribute to greenhouse gas emissions? Can this be measured?

Posted: 23 Jun 2017 07:32 PM PDT

How can I, as a human male, share 45/46 (~98%) of my DNA with a human female, but ~99% with a male chimpanzee?

Posted: 24 Jun 2017 05:15 AM PDT

The 45/46 number is meant to account for the XX / XY difference and the chimp DNA number comes from here: http://www.sciencemag.org/news/2012/06/bonobos-join-chimps-closest-human-relatives

If this doesn't come down to semantics, I will be surprised.

submitted by /u/Bill_Nihilist
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Why isn't there smoke after a lightning in the sky ?

Posted: 23 Jun 2017 09:12 PM PDT

As I understand , lightning happens when oppositely charged clouds of particles come in contact generating light and sound. We know that lightning carries a huge amount of voltage , hence current and heat. My doubt is , when the clouds of particles collide, woudn't the burning of various gasses in the atmosphere cause significant smoke and why don't we see smoke in the skies after lightning ..? Thankyou in advance

submitted by /u/warlock1992
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Since theoretical physics and chemistry exists, why doesn't a theoretical periodic table for exotic atoms?

Posted: 24 Jun 2017 04:40 AM PDT

We all know the periodic table, but exotic atoms such as Muonic Hydrogen, Positronium and Muonium dont have a place in the periodic table. Of course, it would be tedious having a table full of thousands of theoretical atom varieties with one electron switched with a muon or tauon etc, but why not those exotic atoms we have already synthesized? If muons and tauons have more energy and (mass?) & (size?), wouldn't they take up more slots which would give the exotic atom a distinct chemical property?

submitted by /u/Sednaball
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How does having "extra" (more than needed) satellites make GPS more precise?

Posted: 24 Jun 2017 03:23 AM PDT

I understand that 4 satellites are required to calculate a position. Makes sense. But how does receiving the signal of more satellites makes the calculation more precise? How do we know, which signals are better than the others? How is decided which 4 or many possible combinations is used for the calculation. Or how else is dealt with over determined equations for the position calculations?

submitted by /u/idkblk
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Do we know of animals that use plants or certain things in general as medicine when they are wounded or sick?

Posted: 23 Jun 2017 02:14 PM PDT

Are there or have there been cultures where general sexuality isn't considered something "private"?

Posted: 24 Jun 2017 02:50 AM PDT

In my impression it seems that sexuality in "modern" cultures is either something very intimate between people or when it happens "in public" it is most likely a special turn-on for the participants and/or observers. A simple example is a couple being intimate in a public place without the explicit intention to be caught or as another extreme example a swinger club where people explicitly want to be watched. Anyway, these things are considered taboo in all cultures that I know.

But are there or have there been cultures where it is/was completely normal to engage in sexuality in public without it being something considering kinky by the rest of the society? Some cultures in the jungle or islands walk around naked. No big deal for them. In most "modern" cultures one would get arrested.

submitted by /u/idkblk
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