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Sunday, September 3, 2017

Why do clothes feel crunchy when you air dry them, but soft out of the dryer?

Why do clothes feel crunchy when you air dry them, but soft out of the dryer?

Why do clothes feel crunchy when you air dry them, but soft out of the dryer?

Posted: 02 Sep 2017 04:57 PM PDT

Do animals like music? Or at the least, can they recognise the patterns, melodies etc. and react to them?

Posted: 02 Sep 2017 03:03 PM PDT

Why do some people outgrow allergies and some people develop them later in life? And why do some people never outgrow them?

Posted: 02 Sep 2017 05:11 PM PDT

Is there any way to determine the likelihood of whether someone will or won't outgrow their allergies? I feel like I can never find a solid answer to any of these questions.

submitted by /u/Lowfatmilksubstitute
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Did the construction of the Panama and Suez canals affect the ecology of the surrounding waters?

Posted: 02 Sep 2017 03:44 PM PDT

Despite the small overland distance, would connecting two very different bodies of water have a noticeable effect on the flora and fauna of the two regions?

submitted by /u/SpooningThemSoftly
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In light of recent events in North Korea, how do you set off a nuclear bomb underground without causing substantial damage above the blast site?

Posted: 03 Sep 2017 12:06 AM PDT

Reports saying that this was a hydrogen bomb and 10 times more powerful than anything ever previously tested and 5 times more powerful than the Nagasaki bomb which killed 70000 people almost instantly. How is there not like, y'know, a massive crater in the ground where it was or something?

submitted by /u/Farquad4000
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During a supernova, what amount of the star's matter is converted into energy?

Posted: 02 Sep 2017 10:56 PM PDT

It looks like during the lifetime of the sun, .034% of it's mass will be converted into energy via E=MC2. But what about a supernova? Perhaps we can use an A1 type as an example.

submitted by /u/Djerrid
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Can a star have more than one fusion core?

Posted: 02 Sep 2017 04:40 PM PDT

Other than supernova, could for example a blue supergiant/hypergiant have hotspots not in the center that cause fusion?

submitted by /u/UntamedOne
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How are parrots able to repeat and talk?

Posted: 02 Sep 2017 08:20 PM PDT

How are parrots able to memorize and repeat certain noises and words so well?

submitted by /u/stargazer547
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How does the Rfly drone based RFID system developed at MIT work?

Posted: 03 Sep 2017 05:57 AM PDT

The text in the article says:

The drones don't actually carry the RFID reader with them — Adib explains that this added weight basically caused the drone to crash — but rather, relays the signals emitted by the reader over larger distances. "You can take a single reader, whose range is limited to a few centimeters, and send the signal over exponentially larger distances."

So does this mean that the drones are just repeater/amplifiers? Does the reader have that much more bulk? What if two drones transmit the same reader signal and send back the RFID codes at the same time, are there multiple readers waiting for the signal? Do different drones operate on different frequencies?

submitted by /u/snarejunkie
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Is the Planck length constant or does it change as the universe expands?

Posted: 02 Sep 2017 02:31 PM PDT

Also, is space time pixelated by this length, or could you have overlapping of said pixels or lengths, where space-time is actually continuous?

Edit: The title should read "....could it possibly change..." as it might be theoretical.

submitted by /u/jstaylor01
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Does a satellite experience centrifugal force or centripetal force?

Posted: 02 Sep 2017 06:17 PM PDT

Does the quantity or quality of melanin in our skin change as we age?

Posted: 02 Sep 2017 05:17 PM PDT

Is there radiation associated with the creation of a charged particle?

Posted: 02 Sep 2017 06:20 PM PDT

I was studying for E&M and I noticed that radiation fields seem to be accompanied by a changing current somewhere. I then tried to figure out how to get radiation without a current this is the best I got. I know the question is kind of nonphysical since you can't just create a lone electron for example but supposing you could, does that release radiation? I'm assuming there's some delta function like object but I'm not sure.

I recognize that this is kind of a silly question but I wanted to procrastinate and nobody else is in the office with me.

submitted by /u/MarsOfDickstruction
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How does speakers make multiple frequency at once?

Posted: 02 Sep 2017 05:01 PM PDT

So I understand that a speaker oscillates to a specific frequency but how is possible for it to make a mixtures of highs and lows at once

submitted by /u/princehermit
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Why is a kettle so much more efficient than a saucepan at boiling water?

Posted: 02 Sep 2017 10:59 AM PDT

Can someone explain the comparative strength of household magnets?

Posted: 02 Sep 2017 06:18 PM PDT

I'm interested in making household (i.e., refrigerator) magnets as a craft project by gluing some gewgaw to a plain, ordinary magnet. The plasticky "magnet tape" is notoriously weak, and the hard black ones are too big, so I ended up with some neodymium magnets from the hardware store. After some reading, I am worried that these are too strong and may be difficult to remove from a refrigerator without tearing off the gewgaw. Internet research is just getting me a lot of industrial supply company FAQs and Wikipedia articles with tesla measurements. I don't even know what a tesla is a function of: mass of the magnet? area of the pole? something more esoteric? I would appreciate a quick-n-dirty guide comparing household magnet types in some sort of strength-for-size way. Thank you!

submitted by /u/SciviasKnows
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What determines the boiling and freezing points of a substance?

Posted: 02 Sep 2017 03:51 PM PDT

Is there a difference in sound quality when I use the volume control wheel (a variable resistor, I assume) on my headphones as opposed to changing the volume through software?

Posted: 02 Sep 2017 11:19 AM PDT

I understand that it would not necessarily be a noticeable difference; however, is one method of volume control superior in any way? Is it better leave the software volume at its maximum and lower the headphone control as needed, or vice-versa?

submitted by /u/Thundershock97
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Need help Understanding JFET's, Specifically how the depletion region is controlled and its relationship to drain current?

Posted: 02 Sep 2017 01:58 PM PDT

So we just started studying FET's in my Electronics circuits and device theory class, I have a basic understanding of how N-channel JFET's work.

I am having trouble wrapping my head around how the depletion region is affected by VDS/Drain current when VGS is set to 0V. I think the larger the drain current(ID) becomes the more free electrons are "pulled"(not sure if correct term) from the N-type making the depletion region have more positive ions. I am trying to understand what is physically happening in the depletion region when VGS=0 and ID increases.

I also want to understand the other side, Where ID is a function of VGS, How does applying a larger negative voltage make the depletion region larger and how does that effect the resistance of the N-channel.

What is the difference between the depletion region when VGS=0 and ID is at saturation compared with VGS= Some negative value and ID = some lower saturation current. What physically happens to the charges in the depletion region?

I can clarify if what I'm asking is unclear.

submitted by /u/eoin34
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Why do some things burn and some things melt?

Posted: 02 Sep 2017 11:05 AM PDT
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Saturday, September 2, 2017

Does language affect the way a person's vocal chords develop?

Does language affect the way a person's vocal chords develop?

Does language affect the way a person's vocal chords develop?

Posted: 01 Sep 2017 05:58 PM PDT

Is there a limit to how many elements there can be?

Posted: 02 Sep 2017 04:09 AM PDT

What was the weather like in northern parts 13,000 years ago that humans would consider and make the trek from Asia to NA?

Posted: 02 Sep 2017 06:31 AM PDT

Are we capable of fission reactors for electrical space propulsion?

Posted: 02 Sep 2017 05:21 AM PDT

Considering future interplanetary exploration using electrical engines we will need powerful and efficient electrical power sources. As far as I know solar panels are not capable of supplying a mass per kilowatt efficiency required by power heavy engine types like MPD arcjet or Vasimr, especially for the exploration of the gas giants.

Would proper fission reactors (other than the weak RTGs) be feasible in our current technological and industrial capabilities? Or are they currently science fiction?

submitted by /u/88880
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How does electricity get to the load with AC?

Posted: 02 Sep 2017 04:54 AM PDT

Hello reddit,

first of, English is not my native language, so my apologies in advance if I make any mistakes.

I'm an electrical engineering student but I haven't really understood how the electricity gets to the load with alternating current.

I know that with AC, the polarity changes (50Hz in Germany), so the electrons sort of "vibrate" back and forth, therefore they basically stay in the same place.

I've read that not the electrons, but the electric field is the important factor. I just don't understand how the electric field makes the electrical load (correct term? The device that should be powered) work. How does the load get the electricity it needs?

Edit: I've read that the "vibrating" electrons create energy. But what kind of energy? And how does it get to the load? Also, if the electrons aren't really "used" by the load, how does DC work? The electrons flow to one direction, so they have to flow "into" the load at some point. What happens to the electrons then?

I would appreciate some help very much! Sorry if this questions has been answered before.

submitted by /u/SirJoey
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Is motion relative even at the quantum scale?

Posted: 02 Sep 2017 04:31 AM PDT

Do dogs know that cats are cats?

Posted: 01 Sep 2017 05:35 PM PDT

I know that dogs can differentiate between humans and other dogs, and that cats think that humans are essentially weird cats, but do we know what dogs think of cats?

submitted by /u/Thug_Mustard
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Is an electrocardiogram sensing actual current or an electromagnetic field?

Posted: 01 Sep 2017 08:14 PM PDT

I think that the ECG is sensing current, since you need the wet electrode pads and skin impedance is an issue.

I know that the action potential in the heart is created by sodium ion movement through cardiac tissue, which would create an electromagnetic field, but how does that create a current that would travel to where the electrodes are?

Is there some influence on electrons outside the heart that the ECG is sensing? I hope I made my question clear, thanks for taking the time!

submitted by /u/TotallyNotNew
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Have we contaminated space with life from earth?

Posted: 01 Sep 2017 05:48 PM PDT

For example, do we know if the Voyager probes or the Curiosity rover did not carry (living or dead) bacteria, viruses, or other microorganisms (e.g. tardigrades) into space or other planets? Are there normally steps taken before launch to prevent this?

submitted by /u/TrainFan
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Can particles still be entangled when one of the pairs is in a black hole?

Posted: 02 Sep 2017 02:17 AM PDT

If you could detect and measure Hawking radiation, could you tell what was inside of the black hole?

Posted: 01 Sep 2017 10:06 PM PDT

How do astronomers and organizations like NASA determine characteristics of exoplanets such as wind speed and weather?

Posted: 02 Sep 2017 12:41 AM PDT

What holds the nucleus of an atom together?

Posted: 01 Sep 2017 02:40 PM PDT

How does someone develop an allergy?

Posted: 01 Sep 2017 04:32 PM PDT

How does the collapse of a star decay the protons and electrons into neutrons?

Posted: 01 Sep 2017 12:53 PM PDT

So the basic idea of the birth of a neutron star is that the incredibly massive ball of H, He, and other material implode to become a supernova after millions of years in fusion reaction as it consumed and fused the light fusion material into heavier matter. In this 10 seconds the protons and electrons are transmutated into neutrons. But how?

What happens to the particles in the supernova from a particle physics standpoint? Electrons by themselves cannot be made into neutrons since they are leptons, right?

And also why is it that it are specifically neutrons that are favored in this event?

Thank you for reading, and thank you in advance. Cheers!

submitted by /u/88880
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Potentially stupid question, would it be possible to surgically insert magnets into the stumps of people who has lost hands to allow them to pick up metal objects easier?

Posted: 01 Sep 2017 01:50 PM PDT

Is it possible to make a light source that emits an equal intensity of every visible wavelength? Why or why not?

Posted: 01 Sep 2017 12:11 PM PDT

When having children do you physically pass on a piece of your DNA or is a copy of your DNA somehow made and passed on?

Posted: 01 Sep 2017 06:03 PM PDT

DNA is an actual physical thing, right? So if it has a physical shape, what do you guys think?

submitted by /u/T4blespoon
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Will the electrons in the wire of the generator run out?

Posted: 02 Sep 2017 12:00 AM PDT

This sounds like a dumb question. I'm a teen and from my understanding in class. Electricity is produced by cutting a conductor through a magnetic field to "push" the electrons. So when we us electricity, will the electrons be used up and you have to change the metal in the generator or the electrons are still there but just the energy they carry is transferred. I asked my teacher and all he said was "It isn't in the syllabus, don't bother"

submitted by /u/poi_slayer
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Friday, September 1, 2017

How much does drinking a cold drink really affect your body temperature?

How much does drinking a cold drink really affect your body temperature?

How much does drinking a cold drink really affect your body temperature?

Posted: 01 Sep 2017 07:24 AM PDT

Just as "red" in hundred meant "count", does the "ter" in close relatives (like father, mother, brother, sister) mean anything in Old(er) English?

Posted: 01 Sep 2017 07:48 AM PDT

Is the gas in your joints that gets popped when cracking your knuckles the same one that you have to worry about when diving?

Posted: 01 Sep 2017 07:40 AM PDT

Why do female lions kill the cubs of a pride mate?

Posted: 01 Sep 2017 06:25 AM PDT

Hello! I was re-watching the Savage Kingdom, a documentary which shows what you might expect from an African wildlife program but is narrated as though it's some epic drama. Most of the scenes however are what you usually see. Predators hunt prey, drink water, establish territories, etc.

However, in the first episode the supposed dominant female in a pride mates with the male and gives birth to cubs. Two weeks after birth, the other lions find them and start to violently thrash them and then eat them. All the time, the mother is clearly distressed but makes no attempt to stop the others.

The show never attempts to explain it other than 'This is not cruelty on the lions part, this is simply how lions behave'. However, I found it hard to understand the logic of it.

I 100% understand when in the same episode a lion kills a leopard cub. They perceive leopards as competition or a threat to their young, so they kill them whenever possible and the cubs cannot defend themselves. I also understand if a new male comes in and kills the female's offspring so they go back into heat and are ready to mate with him. I could even rationalize if it was a rival female seeing new cubs as a threat to her own pride.

However, I do not understand why they would kill the offspring of their own pride-mate and supposed superior. My friend and I came up with the following theories regarding it, but none seem to stack up.

  • Our first thought was that the female in the documentary is not actually the highest ranking, and that by mating with the male and producing cubs she was seen as defying some higher ranking female. However, even if she isn't technically in the highest standing she is the mother of the newer lionesses, making her a lot older and physically bigger. The fact that she never tries to defend her cubs from younger/weaker assailants made me question this viewpoint.

  • Our second thought was that because the cubs were young they didn't yet smell like lions, and the pride-mates mistook them for leopards, rival lion cubs, or simply just perceived them as food. However, they had been alive for two weeks already and the mother clearly understood what they were.

  • Out last thought is the pride members never meant any harm but were being too rough in their play, and at some point they got so excited they started feeding on them instead of trying to play with them.

So tl;dr, a female lioness who is supposedly the highest ranking female gives birth to cubs away from the pride. Two weeks later the pride finds her, takes the cubs and violently thrashes them, then begins to eat them as they kick and cry out. All along the mother, while clearly distressed, does not attempt to stop her comrades.

submitted by /u/DeneralGegenerate
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What happens to the Intensity Pattern of the Young's Double Slit experiment when the 2 sources (beams of light) are polarized in mutually perpendicular planes?

Posted: 01 Sep 2017 07:55 AM PDT

Amplitude of S1 = A, Intensity = I

Amplitude of S2 = 2A, Intensity = 4I

I know when the 2 beams are polarized in the same plane, the intensity varies sinusoidally between I (destructive interference) and 9I (constructive interference). But what if the beams are polarized in mutually perpendicular planes? A constant 5I?

If the intensity is not constant, then that is the resultant intensity when they meet in phase and out of phase?

submitted by /u/STorrible
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If a human being were crushed down past their Schwarzschild radius, would the resulting black hole pull in enough surrounding matter to sustain itself or would it shortly evaporate in a devastating explosion?

Posted: 31 Aug 2017 11:41 PM PDT

How do we calculate current world population? Also, how accurate is that count?

Posted: 31 Aug 2017 02:56 PM PDT

Burning question on my mind for awhile now. How do scientists calculate the current number of people on the planet? Is it some massive database, clever guesstimation, or something else?

submitted by /u/TwitchFunnyguy77
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When a subsea cable is damaged, how do internet companies know the location where the fault occured?

Posted: 01 Sep 2017 01:43 AM PDT

Intriqued by this article: https://www.itnews.com.au/news/aussie-internet-pain-after-asian-subsea-cables-cut-472070 I asked myself how can they possibly know where the damage is? I mean, with a "normal" cable/wire you can just know if the cable is cut or not, not where it's cut. Do subsea cables have some kind of transmitters installed in them at interval lengths to help narrow down any faults?

submitted by /u/anzezaf
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How does being in space for months affect an astronaut's circadian rythm?

Posted: 31 Aug 2017 03:11 PM PDT

Why are trees in the Sahara flat and wide?

Posted: 31 Aug 2017 08:18 PM PDT

I understand it is a certain species that grow like this, but how is it beneficial to the tree? It seems like it is very important to the animals because of how much shade is provides, but wouldn't the increased surface area on top create issues with more of the tree being exposed to direct sunlight?

submitted by /u/imtakingapooprn
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How do we consistently measure air pressure at sea for the weather charts?

Posted: 01 Sep 2017 05:07 AM PDT

Why do some seagulls have messy feathers small necks and are very aggressive?

Posted: 01 Sep 2017 07:39 AM PDT

Sorry if the title is confusing it's just I always see the occasional 'alpha' looking seagulls. That's wider than others shorter with small necks and have messy feathers. Also they always sqwuack at the innocent ones trying to get a piece of the pie.

submitted by /u/Spoodaman
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Does the human ear have a flat frequency response? Or do we perceive certain frequencies louder than others?

Posted: 31 Aug 2017 04:08 PM PDT

When a boat travels over a water bridge, how does the weight on that bridge change?

Posted: 31 Aug 2017 04:21 PM PDT

Inspired by this picture, I wanted to know if the weight on the bridge would be lighter or heavier while a boat was traversing. My assumption was that it would be lighter, from displacement.

Furthermore, how heavy (as a percentage of the weight of the existing water) could a ship be before it sank or high-centered on the bridge?

https://i.redd.it/42cw78hjq3jz.jpg

submitted by /u/submax
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How do animals that consume venomous creatures metabolize the venom glands?

Posted: 31 Aug 2017 11:09 AM PDT

I just watched this video that National Geographic posted: https://tinyurl.com/ybosw7pg It depicts a rooster attacking and consuming a cobra. I'm curious about how the bird metabolizes the venom. Even if it hasn't been bitten, wouldn't eating the entire animal (specifically the venom gland) be deadly?

submitted by /u/mibergeron
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Is there a front side to a spiderweb?

Posted: 31 Aug 2017 03:15 PM PDT

For several days I've been watching a big ol' spider that has spun a large web on my back porch. Every time I go out to check on the spider it's on the side of the web facing away from the house. Do spiders naturally favor one side of their web over the other side? Is there a front side and a back side?

submitted by /u/thepixelpaint
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How do we determine the half-life of U-238?

Posted: 31 Aug 2017 08:20 PM PDT

From the Institute for Energy and Environmental Research's website:

"Uranium-238, the most prevalent isotope in uranium ore, has a half-life of about 4.5 billion years; that is, half the atoms in any sample will decay in that amount of time."

The key word I'm looking at here is 'any'.

So if you had a sample of two U-238 atoms and wanted to watch it decay, how would you know its half-life if it would take 4.5 billion years?

If one watches the neutrons decay individually over time from one atom of U-238, how long would it take before you see the first neutron decay, allowing you to extrapolate the half-life?

Can you please show your math and how you got to that conclusion?

Thank you.

submitted by /u/Yewnique_Yousurname
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What is the consensus on creatine and its impact on baldness?

Posted: 31 Aug 2017 05:45 PM PDT

I've seen ants huddle together on water to be able to float. How do the ants on the bottom level not drown and die? Or do they?

Posted: 31 Aug 2017 12:12 PM PDT

Is it possible to make a 100kW nuclear reactor that's not an RTG?

Posted: 31 Aug 2017 11:51 AM PDT

I'm looking up "small nuclear reactor" and mostly finding that "small" means "enough to power 50,000 homes". Outside of an RTG, is it possible to go small enough to make a nuclear powered range extender for an electric vehicle? Or are there constraints on the minimum size of nuclear power?

submitted by /u/mutatron
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If Temperature is a measure of the average kinetic energy of particles in a medium, is there something that measures standard deviation?

Posted: 31 Aug 2017 10:39 AM PDT

And if there is a way of measuring the standard deviation, what are the implications of it? My understanding of evaporation is that the higher energy molecules escape the liquid even though the overall temperature is below the boiling point. If the standard deviation of the temperature is lower, would that imply that evaporation would occur at a slower pace?

submitted by /u/sacrelicious2
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London is on a higher latitude than Montreal, why does it snow so rarely in comparison?

Posted: 01 Sep 2017 12:44 AM PDT

Would we be able to see geological evidence of a Harvey-like event from 1,000 years ago?

Posted: 31 Aug 2017 06:18 PM PDT

Given that Hurricane Harvey is being described as a "1,000 year event", do we have any way of seeing if there was a hurricane with flooding of a similar magnitude in the past 1,000 years based upon geological or ecological evidence?

submitted by /u/sacrelicious2
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