Pages

Thursday, September 27, 2018

Do dogs understand pictures of their owners?

Do dogs understand pictures of their owners?


Do dogs understand pictures of their owners?

Posted: 27 Sep 2018 12:30 AM PDT

Why do our teeth not heal or regenerate when cracked or broken?

Posted: 26 Sep 2018 09:15 AM PDT

Every other part of the human body will heal itself to a point. Get a cut? Skin grows back. Break a bone? the body will seal the cracks. Why is it that teeth do not regenerate whatsoever?

submitted by /u/SFgiant55
[link] [comments]

We know the Earth is not perfectly round. Why do we not ever see it in any photos?

Posted: 26 Sep 2018 08:57 PM PDT

Is it just to negligible?

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

How do the Mars orbiters (or rovers) communicate with the earth?How much signal is lost in space and how much time does it take?

Posted: 26 Sep 2018 09:57 PM PDT

Why doesn't the zinc used in galvanic coatings react with oxygen as readily as iron?

Posted: 26 Sep 2018 09:05 PM PDT

I understand that galvanizing iron or steel with a protective coating of zinc can prevent rusting, which is caused by the reaction of the underlying iron with oxygen. But zinc also reacts with oxygen. Why, at the molecular level, is zinc slower or less likely to form zinc oxides than iron is to form iron oxides? Why is zinc, and not some other metal, the most ideal material for galvanization?

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

Can a inductor limit DC transient currents?

Posted: 27 Sep 2018 12:07 AM PDT

Let's say I have a DC constant voltage source. I plug a resistive load subject to voltage transients (infrequently but periodically adding and removing loads at intervals, loads that vary from one steady state to another under operating conditions, etc).

If I want to limit the transient currents while holding the steady state current the same, would using an inductor be appropriate?

Seems like this is a no brainer. Under steady state DC an ideal inductor is just a piece of wire. When subject to a short, sharp voltage rise the current through the inductor doesn't rise right away but rather rises as I = V/R(1-EXP(-t/tau)) where tau is the time constant tau = L/R.

This limits the peak current due to storing the transient of the energy in the magnetic field of the inductor.

Am I missing anything?

is it really this easy to limit DC transients?

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

Why doesn’t the sun’s gravitational pull make us a tiny bit lighter during the day? (when it’s above us)

Posted: 26 Sep 2018 04:04 PM PDT

Why do we have different soaps for different things? What are the differences between, say, shampoo and dishwasher liquid that prevents them from being interchangeable?

Posted: 26 Sep 2018 10:02 AM PDT

Why couldn't we use hand soap in our hair, shampoo for our dishes, dishwasher liquid for our laundry, etc? Are there chemical properties of each that only allow them to be used on certain materials/in certain conditions?

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

Does playing video games actually give you any cognitive benefits?

Posted: 26 Sep 2018 03:05 PM PDT

Up until I read this article, which said that playing video games caused no increase in memory or attention, I was pretty confident that gaming was a good habit. That article only says things about memory and attention though, so what about other things like reaction time, problem solving skills, and coordination? Does it offer any benefits at all?

Edit: Should this be in Neuroscience or Psychology?

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

Why the boiling point of water changes with pressure ?

Posted: 26 Sep 2018 11:40 AM PDT

Today i was in Termodynamics class and my teacher eventually talked about the boiling point of water and said that the boiling point of water goes down as the pressure goes down too.

I couldn't figure it out in my head why this happens...

submitted by /u/Tuareg99
[link] [comments]

Why does certain medicine, like Claritin D, cause me to be drowsy but my workmate to be more "awake"?

Posted: 26 Sep 2018 10:13 AM PDT

I'm drowsy. She hyped. What fuck?

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

How does an eye scan security device work? Is every human eye ball unique like fingerprints?

Posted: 26 Sep 2018 02:46 PM PDT

Are photons from light emitting sources such as a lightbulb, a campfire or the Sun different in anyway physically?

Posted: 26 Sep 2018 10:13 AM PDT

I'm curious to ask those who understand the topic if there's any change in how a photon is made dependent on its origin (and captured) whether by a camera or an organic eye from start to finish. For example are there different types of photons?

Thanks for your valuable time!

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

How do scientists know how molecules look like?

Posted: 26 Sep 2018 02:05 PM PDT

I mean there is this abstract notation of molecules. For example this is the notation of ethanol:

https://upload.wikimedia.org/wikipedia/commons/thumb/d/df/Ethanol-2D-flat.svg/201px-Ethanol-2D-flat.svg.png

But after watching a documentary which threw the notation of random molecules on the screen without much explanation, it left me wondering how people managed to figure out how each and every atom is connected. How did they figure out what is connected to what?

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

What happens if an electron on the "outermost orbit" of an atom absorbs energy (dunno if this is physics or chemistry) ?

Posted: 26 Sep 2018 10:15 AM PDT

Hello, I m not a native english speaker, and in my native language i couldn t find anything on this (or didn t know what i was looking for). (Also, there was something about energy levels, but the orbit thingy in the title sounds better than saying "what happens when electrons with the highest energy level absorb energy"). Anyhow, since i didn t have any chemistry class since 5 years and in my new (apprenticeship? Training? Some sort of school where i learn a job, anyway) we began with pretty basic stuff, like atomic models. My question is, since electrons "jump up" if you make them absorb energy, what happens if you do that to electrons which cannot jump, since there is no further energy level

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

Is it theoretically possible for there to be a 4th dimension?

Posted: 26 Sep 2018 08:34 AM PDT

I always figured it was possible there was some 4th dimension out there that could theoretically be discovered, but how would that work? What other boundaries are there?

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

Is there a method to determine the relative position of an object given its oriention in Earths magnetic field, acceleration and angular velocity(s)?

Posted: 26 Sep 2018 10:08 AM PDT

I am trying to determine the position of an object relative to its origin without using GPS. I have access to a sensor that can provide acceleration, angulary velocity and magnetic orientation and wanted to see if there was a way to use this to determine relative position.

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

Psychologists/Psychiatrists what is it called when someone is attracted to their "saviour"?

Posted: 26 Sep 2018 10:07 AM PDT

Hello there!

So I remember once hearing something about a syndrome describing a victim of sorts falling in love or being attracted to a person that helped or saved them.

To clarify my question let me give you a scenario:

Person is stuck in a burning building - firefighter saves the person - person falls in love/becomes attracted to firefighter.

Now I was wondering what that syndrome is called? That is, assuming it exists and that my memory is not playing tricks on me.

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

Qubits. Why are they different in effect than using multiple bits to determine a single value?

Posted: 26 Sep 2018 10:41 AM PDT

I.e. Qubit = 1, 0, or other

Using two binary bits to determine one value

11 = 1

00 = 0

01, 10 = other

Is it just a matter of efficiency (one qubit vs. multiple binary bits) or am I as stupid as I think I am?

submitted by /u/ELI5-Questions-
[link] [comments]

If two circles make contact externally, how much of the circumference of one actually makes contact with the other? And would that amount equate to an infinitesimal?

Posted: 26 Sep 2018 09:59 AM PDT

Which foods are PRO-angiogenic? When I run a search for this, I only get results about ANTI-angiogenic foods...

Posted: 26 Sep 2018 10:41 AM PDT

https://www.bing.com/search?q=pro+angiogenic+foods

If some foods are anti-angiogenic, some must be pro-angiogenic, right? How come every result is about anti-angiogenic foods, even though I searched for pro-angiogenic?

Are there any pro-angiogenic foods?

submitted by /u/48151_62342
[link] [comments]

Wednesday, September 26, 2018

Do (fighter) airplanes really have an onboard system that warns if someone is target locking it, as computer games and movies make us believe? And if so, how does it work?

Do (fighter) airplanes really have an onboard system that warns if someone is target locking it, as computer games and movies make us believe? And if so, how does it work?


Do (fighter) airplanes really have an onboard system that warns if someone is target locking it, as computer games and movies make us believe? And if so, how does it work?

Posted: 25 Sep 2018 02:51 PM PDT

Have humans always had an all year round "mating season", or is there any research that suggests we could have been seasonal breeders? If so, what caused the change, or if not, why have we never been seasonal breeders?

Posted: 26 Sep 2018 05:01 AM PDT

On the ISS do they have to adjust for flatulence because of the closed loop environment?

Posted: 25 Sep 2018 02:51 PM PDT

How do trees fight off disease?

Posted: 25 Sep 2018 05:13 PM PDT

I'm assuming trees don't have an immune system, so do they have any protection against disease?

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

How do we know a blackhole is spinning?

Posted: 26 Sep 2018 01:12 AM PDT

Iv always been interested in astronomy and physics. But iv been wondering how can you calculate a black hole is spinning or not? Is it by the mass orbeting the black hole? Does a spinning black hole have anything diffrent from a regular non spinning one? Do all black holes spin can a black hole spin at the speed of light would that be possible?

submitted by /u/Redpanda248
[link] [comments]

Ask Anything Wednesday - Engineering, Mathematics, Computer Science

Posted: 26 Sep 2018 08:12 AM PDT

Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Engineering, Mathematics, Computer Science

Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical /r/AskScience post? No question is too big or small for AAW. In this thread you can ask any science-related question! Things like: "What would happen if...", "How will the future...", "If all the rules for 'X' were different...", "Why does my...".

Asking Questions:

Please post your question as a top-level response to this, and our team of panellists will be here to answer and discuss your questions.

The other topic areas will appear in future Ask Anything Wednesdays, so if you have other questions not covered by this weeks theme please either hold on to it until those topics come around, or go and post over in our sister subreddit /r/AskScienceDiscussion , where every day is Ask Anything Wednesday! Off-theme questions in this post will be removed to try and keep the thread a manageable size for both our readers and panellists.

Answering Questions:

Please only answer a posted question if you are an expert in the field. The full guidelines for posting responses in AskScience can be found here. In short, this is a moderated subreddit, and responses which do not meet our quality guidelines will be removed. Remember, peer reviewed sources are always appreciated, and anecdotes are absolutely not appropriate. In general if your answer begins with 'I think', or 'I've heard', then it's not suitable for /r/AskScience.

If you would like to become a member of the AskScience panel, please refer to the information provided here.

Past AskAnythingWednesday posts can be found here.

Ask away!

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

In Chemometrics, how does the Savitzky-Golag Derivation work? And what is Multiplicative Scatter Correction?

Posted: 26 Sep 2018 04:20 AM PDT

What is it about sour candy that makes it sour, and how come some candies are crazy sour and some are disappointing?

Posted: 26 Sep 2018 06:48 AM PDT

I mean comparing candies like Warheads and Sour Skittles (which are some serious pucker-inducing candies) to things like Sour Gummy Worms that aren't sour at all, just sprinkled with a tangy crystal substance?

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

Is it possible to freeze water while electricity is flowing?

Posted: 25 Sep 2018 10:36 PM PDT

When you eat something and get hives, what causes the hives to appear everywhere (even your legs)?

Posted: 25 Sep 2018 09:09 PM PDT

Why can't phone chargers/ charging ports have a higher voltage, thus charging faster?

Posted: 25 Sep 2018 11:40 PM PDT

How do ramjet and scramjet engines deal with the issue of initial propulsion? Do the crafts equipped with such engines need an auxiliary one?

Posted: 26 Sep 2018 12:11 AM PDT

Basically the title. I understand how ramjet and scramjet engines work, but I didn't find how the crafts equipped with these engines take off, basically.

submitted by /u/m1l4droid
[link] [comments]

How do things like squash and pumpkins grow with a hollow cavity inside? What makes up the gas in there and how did it get inside?

Posted: 25 Sep 2018 02:23 PM PDT

Let's say I scrape up my hand. How does the skin grow back exactly the same?

Posted: 25 Sep 2018 11:46 PM PDT

Why are STI tests more accurate after months have passed, instead of a week, from a sexual encounter?

Posted: 26 Sep 2018 02:44 AM PDT

Would it be possible to have STI tests that give accurate results instantly?

submitted by /u/recyclops-robotheart
[link] [comments]

How does light "bounce off" a material?

Posted: 25 Sep 2018 01:17 PM PDT

I understand that when light hits a surface, some light is absorbed (by exciting electrons), and other light is reflected, and it's that reflected light that gives objects their colors. What I don't understand is how atoms/molecules actually "reflect" light? If the light cannot interact with a material, I would expect it to pass through, but this only happens with transparent materials. How do photons bounce off an atom, and what determines whether they bounce off or pass through?

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

Does your body produce insulin in response to consuming Stevia?

Posted: 25 Sep 2018 02:14 PM PDT

More generally, is it the taste of something sweet that generates insulin or does a carbohydrate need to be detected before that response initiates?

submitted by /u/MeVer217
[link] [comments]

Can binary stars have stable lagrange points? If so, have we ever found a planet in one of those lagrange points?

Posted: 25 Sep 2018 09:59 AM PDT

Why are there larger meniscuses in smaller tubes than in larger tubes for water?

Posted: 25 Sep 2018 03:32 PM PDT

Why is it that certain metals like zinc and iron are crucial for our body while other metals like lead and murcury are deadly?

Posted: 25 Sep 2018 01:41 PM PDT

Are there any drugs that have stopped being used because the disease evolved total resistance to it?

Posted: 25 Sep 2018 06:20 AM PDT

To which point(s) is the system of latitude and longitude fixed, since the continents are actually constantly moving?

Posted: 25 Sep 2018 01:46 PM PDT

Or in other words; how do I make use of the grid system when looking at a map of for example Pangea?

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

Is body fat percentage correlated with how long someone can endure starvation before death?

Posted: 25 Sep 2018 11:06 AM PDT

Let's say two people wash up on a deserted island. One with 7% body fat and one with 32% body fat. They have access to a reliable water source however there is no food on the island. Would the individual with a higher body fat percentage be able to survive through starvation longer than the other? Logically I would assume that because there is more energy stored and available for use they would survive longer, however I've not seen any meaningful data supporting that notion.

submitted by /u/gravyboat15
[link] [comments]

Tuesday, September 25, 2018

What could have caused a violent reaction between 2 store-bought pool chlorine brands?

What could have caused a violent reaction between 2 store-bought pool chlorine brands?


What could have caused a violent reaction between 2 store-bought pool chlorine brands?

Posted: 25 Sep 2018 04:40 AM PDT

A Tale of Two Chlorines

Can someone please explain why I had a sturdy plastic bucket literally explode into fragments when I mixed 2 different brands of pool chlorine together? I've never seen something explode like that when exposed to open air.

So what I would normally do is mix the chlorine with pool water and then pour everything into the pool, no problem.

One day we switched chlorine brands, so I poured the last little bit of the original chlorine into the bucket (there might have been a little water in the bucket to begin with) and topped up with the new chlorine. I noticed vapor coming off the mixture almost immediately as I started mixing. The reaction started bubbling and boiling and within about 10 seconds, the mixture started putting out a thick yellow cloud. This was when I knew I had to GTFO, mainly to avoid breathing in any of the noxious fumes. I can't quite remember if I was going to call someone or to get water to dilute the mixture.

I turned around and started walking and as I turned a corner about 5 meters away from where the bucket was left standing, I heard an incredibly loud bang and saw pieces of the red bucket fly past me and land in the pool and on the lawn over 10 meters away. There was literally nothing left at ground zero other than a few white stains from the powder. It was a really powerful explosion.

This happened quite some years ago when I used to look after the pool at home, so the details may be a bit sketchy. I've always thought about that incident, what if I hadn't moved away? I could have been permanently blinded, or developed some kind of respiratory issue, possibly even hearing damage?

P.S. the brands were HTH and Clarity in that order (i think)

There was no outside contamination that I know of.

Edit: Thanks for the replies and explanations so far. I'm glad I'm not the only one surprised/confused by this. Just a couple things, This was a long time ago like I said, so it might not have bubbled for 10 seconds, the gas might have been green instead of yellow, etc. All I know for sure is that it was loud, it started raining red plastic bits, there was definitely no lid on the bucket and that there were 2 brands of chlorine in a bucket.

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

How exactly is unused breast milk absorbed back into the bloodstream?

Posted: 24 Sep 2018 05:56 PM PDT

I read somewhere that whatever milk is left in the breast after weaning gets absorbed back into the body. But what exactly is happening there? How is the body able to absorb nutrients without involving the digestive tract?

I hope these are not extraordinarily dumb questions. I only have middle school level background in biology (and most other things).

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

In the quantum chemistry model why don't the negatively charged electrons fly into the positively charged nucleus?

Posted: 25 Sep 2018 06:25 AM PDT

In the Bohr-Rutherford model it makes sense why they wouldn't because it's just like why the planets in our solar system don't fly into the sun. But, in quantum chemistry you have stuff like P orbitals which look like 8's in which 1 electron is found in each loop so they dont rotate around the nucleus completely. Why don't they make contact with the nucleus?

submitted by /u/Phobac07
[link] [comments]

How do scientists manage to find the exact masses of different atoms when then they were first discovered?

Posted: 25 Sep 2018 02:37 AM PDT

What happens when a nebula made of non-simple molecules begins accretion?

Posted: 24 Sep 2018 03:50 PM PDT

For example, the area designated W3(OH) is a nebula of primarily methyl alcohol. What happens when angular momentum begins an accretion disk? I thought hydrogen and helium would create a nursery for new stars, but in the case of other molecules does a protostar form, or what happens next?

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

If you have a family history of cancer, are you at risk for cancer in general or just the type of cancer(s) your relative(s) had?

Posted: 24 Sep 2018 02:58 PM PDT

So for instance, my aunt had breast cancer. As a male, my risk of getting breast cancer is still relatively low. However, does that also mean I am more likely to get any type?

submitted by /u/Boba3964
[link] [comments]

When was the last time molten lava was naturally present on the surface in the continental USA?

Posted: 24 Sep 2018 11:56 AM PDT

I know the lower 48 states have lots of volcanoes, particularly on the west coast, and there have even been some relatively recent eruptions (most famously Mount St. Helens). But to my knowledge, those recent eruptions have been explosive gas and ash, not lava. The presence of massive ancient lava flows in states like Idaho and New Mexico indicate that volcanoes with lava do exist in these though.

Basically, what I'm wanting to know is when the last time there was a Hawaiian-style eruption with flowing lava, and/or molten lava present on the surface, even if not part of a major eruption -- there's not a place like this in the continental USA currently, right?

submitted by /u/xj20
[link] [comments]

Is a sound’s volume tied to its range?

Posted: 24 Sep 2018 01:52 PM PDT

In other words could you make something be heard from farther while maintaining the original volume. Also does an increase in volume always mean it will be heard from farther ? And could you make a speaker that is the same volume from every distance ?

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

How a Doppler ultrasound works?

Posted: 24 Sep 2018 05:58 PM PDT

It's possible to build up a homemade Doppler ultrasound?

submitted by /u/Pkt27
[link] [comments]

In a galaxy, how much gas and dust would have to be present to prevent being about to see out of the galaxy in the visible spectrum?

Posted: 25 Sep 2018 01:27 AM PDT

As I understand it, we're unable to see across tongue other side of the Milky Way at least partially because there is too much gas and dust in the way. If the solar system were deeper into the galaxy where there's more dust and gas, or if the galaxy were less flat, could there ever be enough dust and gas to prevent us from seeing out of the galaxy entirely?

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

How do various vitamins/minerals actually get used in our body?

Posted: 24 Sep 2018 10:31 AM PDT

Like on a physiological level, how does the zinc, vitamin C (or D, B's, etc), or whatever else actually work? How do they get used by our cells? Please drop some knowledge on whichever vitamin/mineral you can shed some light on!

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

What is the difference between radiation that transfers heat and the radiation that we associate with radioactive substances?

Posted: 24 Sep 2018 08:11 AM PDT

So I learned in class that radiation is a form of heat transfer. Is this difference than say, the radiation from nuclear explosions?

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

What do we know about ancient gut microbiomes?

Posted: 24 Sep 2018 07:47 AM PDT

I know that we are just starting work on understanding the differences between gut microbiomes among modern populations. How much work has been done on sequencing the traces of gut microbiomes in ancient latrines?

Do we know anything at all about the gut microbiomes of Neanderthals?

submitted by /u/Prufrock451
[link] [comments]

Would Outer Space be an effective coolant?

Posted: 24 Sep 2018 09:20 PM PDT

As opposed to something like nanofluids or liquid nitrogen, or even helium 3/4. I know that outer space is cold. (2.7K) But you also cant pump it around, and sometimes external radiation is a problem. I know the ISS uses radiators to get rid of its waste heat, but it doesn't have large reactor and doesn't use much power, let alone all that it uses. Basically, if you were going to put a ridiculously hot reactor on a giant space ship, would it make more sense to have outer space just cool it off for you than to use something else? What would be the advantage/disadvantages of using space to cool your reactor?

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

Dating in archeology and geology depend largely on the fact that there are layers of earth/ice. Is the earth getting bigger as these layers are added?

Posted: 24 Sep 2018 12:19 PM PDT

What gives Polyester it's useful properties?

Posted: 24 Sep 2018 01:48 PM PDT

I know that when Polyester is made into fabrics, the stretching forces the molecules into parallel patterns, giving the material more tensile strength, etc. What I want to know specifically: Why is it shatterproof? Why is it hydrophobic?

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

Why does red print appear to move on a blue background?

Posted: 24 Sep 2018 07:09 AM PDT

Why is smoke seemingly unaffected by gravity?

Posted: 24 Sep 2018 11:57 AM PDT

Why is the polio vaccine still needed in the US?

Posted: 24 Sep 2018 06:27 AM PDT

Was doing some research and just want to understand. Polio is only transmitted through fecal matter getting into someone else mouth - either infected food, water, etc.

Do we not have enough technological advances on food and water cleanliness that the vaccine is merely not needed any more? The only places that seem to still have polio (at a very low rate at that) are places where cleanliness can be hard to come by.

Apparently the vaccine is only 95% effective, and 5% of people it is administered to will not be truly 'safe' from getting Polio, but still there are no reported cases in the Americas since 1991.

Averaging 4 million births a year in the US from 1994 to now is 96 million people, 4.8 of which would not have the vaccine being effective. Still no cases. So why is the vaccine needed?

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

What are the Hessdalen lights?

Posted: 24 Sep 2018 01:31 PM PDT