post_title
stringlengths 9
303
| post_text
stringlengths 0
37.5k
| comment_text
stringlengths 200
7.65k
| comment_score
int64 10
32.7k
| post_score
int64 15
83.1k
|
|---|---|---|---|---|
ELI5: How did humans learn to extract metal from rocks? | This is something that has always perplexed me. How the hell did our ancestors learn that putting certain types of rocks in 2000 degree furnaces would yield a useful material for weapons and tools? | Certain metals like gold, small amounts of iron, etc. can be found in their natural form without smelting. As time went one our ancestors learned that other metals could be extracted from rocks by heating them. Not all metals require insane temperatures to smelt either. Some of the early attempts could also have been accidental as hearth stones that contained ore were heated and we observed that metal came out of them. | 11 | 25 |
CMV: Romantic relationships in high school are not worth the trouble | When someone is in high school, it does not make sense to have a committed romantic relationship. Romantic relationship is defined as a mutual agreement of exclusivity in dating, and being referred to as together.
The first point I have is that in a purely practical sense, dating should be seen from a breadth first approach. It is more pragmatic to date many people and learn what your particular tastes are than to learn it by stumbling through a series of relationships that fall apart and tripping right into the next one. This is emotionally taxing.
Second, as teenagers have not matured enough yet to what they will be as adults. You can't really understand the significance of that intimacy at that time. One just is not ready until a later age
Third, relationships are distracting, expensive and time consuming. High school is often what decides the course of someone's life, and it is not wise to mess with something that powerful. I have seen many people throw their lives away for their boyfriend or girlfriend, and it seems that it just is not worth the risk.
EDIT: Please note I am only saying that people shouldn't get into serious relationships, not that dating should stop altogether.
Answer this and I will be convinced; Is it vital that someone gets relationship experience in high school? Would in not be bennifical to date noncommittally until after graduation?
To support this I point to the statistic brought up by u/tomrhod:
>The key is that the research shows that starting in the 1980s education, specifically a college degree for women, began to create a substantial divergence in marital outcomes, with the divorce rate for college-educated women dropping to about 20 percent, half the rate for non-college educated women. Even this is more complex, since the non-college educated women marry younger and are poorer than their college grad peers. These two factors, age at marriage and income level, have strong relationships to divorce rates; the older the partners and the higher the income, the more likely the couple stays married.
... A closer look at even these lower rates indicate that there are really two separate groups with very different rates: a woman who is over 25, has a college degree, and an independent income has only a 20 percent probability of her marriage ending in divorce; a woman who marries younger than 25, without a college degree and lacking an independent income has a 40 percent probability of her marriage ending in divorce.
Please, CMV
Edit 2:
The multitude of stories changed my view. Thanks!
_____
> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | The earlier you have your first serious relationship, the earlier you mature and become better at having serious relationships. Your first relationship is always going to be a learning experience, why not have it when you are young? | 134 | 67 |
CMV: Prisoners being forced to work isn't the same as slavery and is OK with some protections and caveats | So starting off with there are huge problems with the prison industrial complex and how prisons don't reform inmates and issues with them returning to a normal life. I'm generally in favor of many reforms here. That said, I have no issues with prisoners being forced to work if they are found guilty and serving time. I think the conditions should be humane, safe, and not demeaning. Inmates with health conditions or advanced age would be exempt or fill roles they are suited for. I think anyone contracting them should pay market wages. I think any wages or profits or savings should go directly to upkeep and maintenance of the facilities, quality of life improvements for inmates, restitution for victims, and programs to help them transition back to a normal life so it removes the incentive to just lock people up. What am I missing? | Setting aside the moral aspects for a moment.
What does allowing the indentured servitude of prisoners incentivise?
The prisons profit off the labour of their prisoners. This means that there is an incentive to have more prisoners.
So why would a prison attempt to reform a prisoner? Reform is an expense, and denies the prison an asset in the future when the prisoner is less likely to re-offend. It also creates the incentive to imprison people for minor and non-violent crimes, because more prisoners means more money.
Imprisoning someone should always be an expense, because it is a punishment society should be using responsibly and only where strictly necessary. | 32 | 28 |
Eli5: How can spacecraft determine their speed once out in space? | There are a number of ways, but one is by measuring the frequency of the radio signal it receives from Earth. The signal is sent at a precise frequency, but because the spacecraft is moving - normally away from earth - the frequency is 'doppler shifted' down - because between each peak in the radio wave and the next, the craft has travelled a little further away, so it takes a little longer for it to arrive. From this the craft can calculate the speed with respect to Earth, and as it knows, from its programming, where and how fast the Earth would be at this time, and the orbit it is in and what direction it is travelling, it can calculate its speed. | 22 | 23 |
|
ELI5: If an exoplanet like Kepler 442b, the most likely to be habitable exoplanet, has a mass 2.34x that of earth, would the gravity of the planet be 2.34x that of earth as well? Also, how would this affect humans if they were to travel there? | Depends on the size of the planet. Gravity increases proportionately with mass but inversely proportionately with the square of the distance.
Consider the Moon. The mass is 0.0123x Earth, but its (equatorial) radius is 0.2725x Earth. Combining these gives us:
(0.0123/0.2725^(2)) = 0.1656... which is around 1/6th the gravity of Earth, which is what we observe.
So, if Kepler 442b was simply 2.34 the mass of Earth but also the same size then, yes, it would be 2.34x the gravity of Earth. But it's radius is 1.34x Earth which gives us:
(2.34/1.34^(2)) = 1.3032... so it is about 30% more gravity than Earth. | 174 | 147 |
|
ELI5: Why is light brighter in peripheral vision then direct vision in the dark | There are two kinds of light sensitive cells in the eye.
Rods are sensitive to low levels of light but only see in black and white and things kind of look fuzzy because they are good at collecting light, but that means they are not very precise.
Cones see in color and are very precise, but that means they are not very efficient at collecting light.
The centre of your eye is packed with cones which is why you can see very good details when you look right at something. Cones are sparse in your peripheral vision so you see less detail.
In very dim light you are seeing with only rods. If you look at the sky you will see dim stars in your peripheral vision that disappear if you look right at them. That's because there are so many cones in the centre of your eye there is no room left for rods. | 17 | 24 |
|
Why do so many flying insects have aquatic larvae? | Aquatic larvae allow juveniles and adults to exploit different environments and resources. This prevents competition between different life stages of the same species and allows both stages to maximize the resources in their particular environment. Additionally, larvae tend to be much smaller than adults, and the body plans of adults may not be well suited to significantly smaller dimensions, so a different body plan (in this case, one adapted to an aquatic environment) can be advantageous as the larva grows in size. Finally, separating adults from larvae may also serve to protect a population from environmental catastrophe, as terrestrial and aquatic environments are likely to be affected differently from such adverse events. | 15 | 56 |
|
CMV: I find difficulty in supporting abortion. | I want to make this thread as a genuine opportunity to see some info and get some opinions that can change my view, as i am clearly in the minority, especially on Reddit. I dont know if I’m missing something, but I just find it hard to support.
First, i need to point out that I am on board with abortions for things such as the health of the mother or child being compromised, rape, incest, those sort of situations. I also feel it may be necessary to point out that I am not a particularly religious person, I think I would fall in line with agnosticism.
I see many people saying to believe in science, and that saying that life begins at conception is blatant misinformation. I then found this;
https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3211703
So that part is concrete to me.
My other reasoning is I do feel it falls to accountability for actions. I’m not saying to be, and realize it is unrealistic to expect, abstinence across the board. But the thing is, we have many forms of protection, condoms, plan b, birth control, all very effective. I know that it isnt a guarantee, and if by chance that all fails, that is very unfortunate. But that is the risk everyone knows, and takes. Reproduction is literally the point of sex. Im not saying that is or should be the only reason people have sex, but that is what it is for. It seems entirely unfair and wrong to end an unborn child’s life, because you made a mistake, or an accident happened. The “my body my choice” view seems simply wrong due to it being the childs body, the childs life.
For me, and obviously cant speak for everyone who doesnt support abortion, it has nothing to do with supposedly trying to control womens bodies. Get your tubes tied, men can get their nuts snipped. I do not see any arguments (besides mentioned at the top) for getting an abortion, and yes, ending a babies life. Not being able to afford it, not wanting it, thats things you need to consider before hooking up with people, and make sure to take the proper precautions, and if it all fails, again that is unfortunate, but you know what the risk is. I find it completely unfair to just end the babies life because of a mistake or accident.
Where am I going wrong? What am I missing? To me this seems reasonable, but I am very clearly in the minority, and people like to think I’m some piece of shit who want to control women or something | 1) The paper that you linked is not peer reviewed. It is a supposed study conducted by the director of Illinois Right to Life. Specifically, he asked biologists this question: "“In developmental biology, fertilization marks the beginning of a human's life since that process produces an organism with a human genome that has begun to develop in the first stage of the human life cycle.” Even abortion advocates would agree with that statement. The fact that it is the beginning of the process does not mean that it is yet a human life. This is an attempt at designing and conducting a study for a gotcha moment.
2) Why does there have to be a consequence for not being careful with sex? That assumes from the beginning that sex not for the purpose of procreation is a bad thing. We seek, as a culture, to eliminate consequences for all sorts of decisions. We have rehab clinics for those who get addicted to drugs or alcohol. We have weight loss programs for the obese. We have programs to help people get rid of criminal backgrounds. We get rid of consequences all the time and society hasn't collapsed.
3) Your view assumes that the fetus is worth saving as soon as the sperm hits the egg. At that stage of development, the fetus is only a few cells large. Most ethicists would put the human life somewhere later in development - when it can detect pain, or when it can register brain waves. That happens at around 18 weeks, far after Texas' 6-week ban.
4) Having a child is incredibly demanding on the mother. The mother may have gotten a college degree that she can no longer use because she will have to, as a single parent, take care of a child. She may have to quit her job. Having a child may mean that she is a less attractive prospect for marriage. Mothers should not be forced into this situation without an extremely compelling countervailing interest. | 3,532 | 1,467 |
Why are some common lab-grade reagents used in food production, such as NaCl, labeled as "lab use only" and "not for consumption"? | I have a 12 gallon HDPE chemical container with a NaCl MSDS attached to it. I want to use for storage of food grade liquids, but the container says the NaCl is for lab use only and not for consumption. By all accounts, my other containers should not be used for storage as they once held acids of various types. If cleaned and sanitized using food-safe chemicals, why should I not use these NaCl containers? | Chemicals intended for human consumption need to be handled in more stringent environments than research chemicals. For research chemicals, nobody freaks out if the reactor you used to crystallize sodium chloride was used to crystallize sodium cyanide the week before. But they would if people were going to consume that salt. If a chemical is meant to be eaten, it must also go through additional testing to ensure that it's not contaminated with specific toxic substances. There are no regulations about what research chemicals can be contaminated with. Researchers do typically demand that their chemicals be analyzed so they know what they're using, though.
Containers are the same. Plastics can be contaminated with all sorts of plasticizers and catalysts that you don't want to eat. Food grade plastics have minimized those impurities. Chemical storage plastics are chosen for their durability, not their lack of toxicity.
I don't see any reason to risk it. Buy food safe containers. | 30 | 15 |
Why are Neanderthals considered a different species from humans if we could interbreed and produce fertile offspring? | I've often heard the word species defined as the largest group of organisms that can interbreed and produce fertile offspring, if that is the case why do we consider Neanderthals a different species when many people today have Neanderthal ancestry? | species are more about having a distinct gene pool with little or no outside interbreeding, and neanderthals had that for a long time and so developed a genetic distinction of their own, becoming a separate species.
basically they are a different species because they formed a isolated group that didn't interbreed extensively for a long time and therefor evolved differently from other humanoids. the fact we could still interbreed is irrelevant to them being a separate species or not.
the thing is, the term species isn't as clear cut as most people believe. what exactly the crossover point between being a separate species and not being one isn't based on clear easily identified criteria. | 12 | 44 |
How much more would gas prices need to rise for people to start taking public transportation (Elasticity, Supply and Demand) | This is a very difficult question to answer as it will depend on the region and access to adequate public transport, population of said region, disposable income after essentials like food/power/etc per capita of said region, WFH policies, average commute miles per capita, average leisure driving miles per capita, inflationary impact of said region, etc.
For many across the US, there is no true public transportation alternative. For example, in Texas there are many cities where a 18-20 drive to work easily becomes 1.5 hours (one way!) along with a 10 minute walk if you try and take the bus, making public transportation a non-starter for most.
And if more people move over to said public transport, the system may not be set up for such a surge and wait times could increase significantly, pushing people back to cars. | 44 | 64 |
|
Why exactly is a 100% efficient process impossible? | So I've built a perpetual motion device and need your help...
No, actually I'm a BSc Physics grad working on a book and trying to sort some things out in my head. I've been doing a bunch of reading on the topic and am trying to pin down one particular point. I get the basics of the four laws of thermodynamics, I remember the statistical explanations of entropy, and (actually, mostly thanks to a few reddit posts), I'm starting to get a hold of the idea of heat being "unusable" energy.
Ok, so my actual question is this: How valid is it to say that you cannot reach 100% efficiency because you cannot escape friction, and friction always results in a heat transfer? Am I thinking on too much of a macro level?
Thanks for any help you can give. | Friction is a good culprit in mechanical systems, but equivalent types of loss occur in other systems (e.g. viscosity leads to drag in fluids; randomization of electron paths leads to ohmic resistance in electrical systems).
I think the concept you're reaching for is this: it is never, in practice, possible to create a completely ordered system, and slight amounts of disorder in any energy-transducing system will yield loss of ordered energy (mechanical, electrical, chemical) to disordered energy (heat at uniform temperature). Friction is due to lack of order in the physical shape of sliding solids on the molecular scale, or to viscosity in liquids or gases -- which in turn is due to momentum transfer by disordered molecular motion perpendicular to applied shear. Electrical resistance is due to disorder in the electron-nucleus interaction in a conductor. Etc.
The problem is that such statements have to be so general (to encompass all the forms of disorder and of ordered energy) that they just boil down to restatements of the second law of thermodynamics. | 25 | 23 |
ELI5: Why are mascots a big part of American sports but not so much in Europe? | The focus on American sports tends to be more about the teams and the team franchise identity, when in Europe the focus is a lot more on locale. This came up a bit on a question a while back when someone was asking about how US teams can so easily change owners or cities compared to European teams. Because most American sports are only maybe 150 years old tops and organized play groups are mostly less than 100 years old, there isn't nearly as much history. The oldest European Football team (Notts County) has been active since 1862. The oldest American Football team, by comparison (The Green Bay Packers) joined the NFL officially in 1921.
The focus on the franchise of the team versus the locale is also impacted by the relative size of the countries. It's easy to find a local team to support in England, where the UK club system can have hundreds of teams across all the various levels. There are 92 teams in the first four levels *alone*, while in the entirety of the NFL there are only 32 teams. Even just going with Level 1 teams, there's approximately 1 team for every 2,500 square miles in England, and in the NFL there's one team for ever **12,000,000** square miles.
So it's a lot easier to associate with a franchise than a location, especially when that location might be five states over. And part of creating that franchise is by creating a mascot or icon to rally behind. | 10 | 24 |
|
How do we establish elevation on another planet that has no ocean, ex. Mars? | Do we pick the lowest point on the planet and call that zero? Or what do we use for "zero" elevation, when there is no ocean? | On Mars we use atmospheric pressure to determine at what elevation water molecules would no longer be stable if they WERE present (6.105 mbar) and use that as a reference point that’s similar to our sea level. It’s called the Mars areoid. | 92 | 105 |
ELI5: Is it true that hanging towels, clothing, etc. out in the sun naturally deodorizes it? If so, how does that work? | Trying to figure out whether or not this is just an old wives tale or if there's some kind of chemical change that comes in the sunlight that destroys odors. Also, is the deodorizing effect only temporary, or permanent? Does the sun actually destroy or just mask odors from mold, etc? Thanks in advance! | The "livestock" living on your towels/clothing need a warm, wet and semi dark to dark environment.
Placing them in the sun removes the water. Water is very necessary for life.
Imagine if you got lost in the middle of a desert. No water, too much sun, little to no food. Your ability to survive would be dependent on finding shade and water.
So basically putting clothing or towels in the sun causes desertification of their little ecosystem. | 30 | 76 |
Do straight lines exist in nature? | If straight lines do exist in our natural environment, do we have any really good examples?
Edit: Spelling
Edit 2: So as I understand it straight lines depend on scale, do we have any examples of vastly large straight lines? (over a mile) Or anything larger than a crystal? (we'll say larger than 2cm) | That depends on the scale of what you're considering, and how much wiggle room you're willing to give.
Crystals can have remarkably straight and precise edges, but if you were to look at them in a microscope, they'd probably be pretty jagged.
Rock scoring left by glaciers can be pretty straight, too.
Geological strata in exposed rocks.
The trails left by sailing stones.
| 66 | 90 |
ELI5: How does a change in the number of protons/neutrons/electrons drastically change a molecules properties? | It's like I add a few electrons and neutrons and protons and BOOM, went from hydrogen to copper or copper to neon.
How does a simple change in a molecule's structure determine the chemical and physical properties of an atom? | The structure is what determines how it interacts with everything around it.
Think of a molecule like a key, and the rest of the universe is a set of keyholes. The protons and electrons and neutrons---their positions, charge, number, and other properties---are like the grooves and teeth on the key. If you change those things in even a small way, it will dramatically alter what keyholes the key will fit. | 15 | 35 |
[The Truman Show] What kind of lawsuit Truman can fill against the TV Producers of the show? | What was done to him is pretty heavy, and there are literally lots of people involved. But starting from the very creator and director of the show... What kind of criminal charges can fall upon him if Truman decides to take legal action? | Slavery, violation of privacy, sexual assualt, rape, illegal imprisonment, back pay and wages, copyright and trademark infringement, coercion, mental duress and trauma. The list goes on and on. But a corporate entity cannot be named guardian of a child and any consent or rights waivers his mother signed would have expired on his 18th birthday. He was forced to stay in the town despite several attempts to leave. Forced to perform and work without pay commensurate to his labor. Engaged in sexual relations where consent would be impossible (actors playing a role can't consent because their characters consented, but it's dubious because it opens up a can of worms legally speaking for anyone that's hired an escort to sleep with someone else unknown to them). Products sold and marketing using his face without his permission or monetary compensation. It'd be a landmark case and enough public support would be behind Truman from the fans that he would be hard pressed to find an unsympathetic or nuetral court to hear the case. | 43 | 30 |
ELI5: When people talk about "rendering" a video for x amount of time, what is the process that is taking place? | Do they leave the computer turned on until the video renders? What about a video that takes weeks, or even years? | Basically the computer program needs to calculate what exactly will appear on each point of the screen, for each frame. It needs to take into consideration the objects that are in the scene, their location and appearance (colors, textures etc.) and especially the lighting.
> Do they leave the computer turned on until the video renders?
Yes.
> What about a video that takes weeks, or even years?
Each frame of the video can be rendered separately. This allows the rendering process to easily split to multiple computers on a server farm - instead of having one computer work for 5 years, you can have 100 computers work for two and a half weeks. | 33 | 53 |
What makes online forums so prone to disinformation? | Don't really have time to explain them, but you might be interested in the disinhibition effect, affective communities (Papacharissi), and how algorithms encourage/facilitate the formation of echo chambers. | 11 | 21 |
|
CMV: We're living through the best period of human history there has ever been - people globally have never had it better. | Modern humans are safer, richer, smarter, healthier, and happier than humans have ever been before. Let's say 'modern' is approximately since the turn of the millennium. I think you can apply any metric to this and the conclusion is the same - our species is at its greatest point in time, so far.
There's a huge amount of sensationalism and doom flowing from both sides of the political spectrum, through media and the politicians themselves. It's easy to buckle under the pressure and perceive humanity in a negative light. It's easy to woe at the state of the world, as if there isn't an unfathomable amount to be proud of in our history, which has brought us to this point of relative greatness.
Poverty is at a record low, violence is at a record low, scientific progress is at a record high, medicine is at a record high, individual freedom is at a record high, oppression is at a record low. I can dig up sources for this but its intuitive - *surely* this is the greatest of all times.
Change my view, through any means, statistical or philosophical. I'm interested if my optimism is as flawed as the pessimism I see regularly and dismiss quickly. | It depends what metric you use. From an environmental standpoint, the world is way more overpopulated than it was 20 years ago. The effects of climate change are being noticed. Natural disasters are doing more damage to more people.
Since 9/11 fear of terrorism has skyrocketed, and airline travel and border security worldwide has become much more strict, and thus less convenient.
24 hour news has increased our exposure to news, but has decreased the quality of news. News outlets tend to focus more on emotional response and less on fact reporting. It is difficult to get an unbiassed opinion, even with all the knowledge we have at our finger tips.
We are living in a time of constant surveillance, and personal privacy is at an all time low.
Mental health, though less stigmatized, appears to be more rampant. Cyber bullying and social media addiction are adding to the issue.
Workers, more than ever, are expected to be on-call 24/7, and fluent in technology. Jobs, even at the entry level, are requiring multiple years of experience and multiple degrees. College tuition and books are getting increasingly more expensive.
Minimum wage has not risen with inflation in most countries. Housing is comparably expensive. Fuel prices are very high. We have much more expenses to deal with such as cell phone bills. So it's harder to live day to day. | 16 | 73 |
We know DNA -> amino acids -> proteins sequence. How are the non-protein structures encoded, for instance lipid walls, chlorophyll, hema? | We know DNA encodes for 21 amino acids used by ribosomes to build proteins.
However there are many structures which are not made out of amino-acids. Examples are the cell lipid wall, parts of the respiratory and photosyntesis systems, chlorophyll, hema.
What encodes for the non protein structures in the cell?
Here are the components of Photosystem I in plants:
17 proteins
4 lipids
5 pigments
5 co-enzymes
http://en.wikipedia.org/wiki/Photosystem_I
| They are formed by enzymes, which are proteins themselves and therefore determined by a sequence in your genome, or extracted or retrieved from the food. Further elaboration is possible, but that's basically it. | 33 | 30 |
ELI5, Why is the amount of water required for producing something (food, clothes, etc..) used as a measure of sustainability? | I get that if it’s produced somewhere where water is scarce it’s important not to waste it but where I live freshwater is incredibly abundant why does it still matter? | Industrial production tends to use massive amounts of ressources. If not well managed, even the most abundant of ressources can become depleted given enough time.
Another reason is that industrial processes often cause pollution and if not managed (often mandated by law), polluted water could be dumped back into the environment. The water may not be reusable without (heavy) treatment, therefore not sustainable for the long term.
Another reason could be that a big corporation could set up shop in an area, exploit the ressources without caring about the environment. Once the ressource is depleted or the market has dried up, the corporation leaves. The local inhabitants are now left economically deprived in a degraded environment which could have been better preserved when the moneyed corporation still had an interest in the area. | 85 | 84 |
CMV: The Nordic countries are not socialist | First of all, I should say I don’t consider myself socialist, but I agree with a lot of the criticism against capitalism.
What has baffled me is this - I see a lot of people here in reddit state that the Nordic countries are socialist, but I hadn’t heard this point of view anywhere else. I’m Bulgarian and my country has a socialist past and if I compare that to the Nordic countries now there’s almost no similarity in how the systems work.
Socialism is about state-controlled market, but the Nordic countries have a free market. Also, in socialism all businesses are nationalized, as was the case in Bulgaria, but in the Nordic countries most of them aren’t.
I read someone mention that in Norway the oil industry is state-owned, and the state has a bank (but not all banks), but that is still far from the idea of socialism.
I also haven’t heard anyone from the Nordic countries describe their model as socialist. I feel people might be mixing up the words social and socialist, but social policies can be found in a lot of countries and they do not result in a socialist system.
I am really curious to understand why people consider the Nordic countries socialist.
Edit: In addition, someone recently referred this article to me - https://en.m.wikipedia.org/wiki/Nordic_model - as proof that the model is socialist, but it even goes to say that it is based on free market capitalism. It does mention social policies, but I still don’t understand why people take that to mean socialist. | Words are defined by who uses them.
And there are a lot of people who use the word socialism for things that by your definitions are merely capitalism with a social welfare system.
This is especially prevalent in the US, where the term socialist is often used by the right to criticize normal government welfare projects on the left. Parts of the left have responded by embracing the term, taking away the danger of the accusation by changing the definition to be something positive.
As a result, the meaning, especially in US contexts, often doesn't refer to governement controlled economies, but just to social welfare systems. | 21 | 17 |
Is Computer Science A Good Career Choice? | Hello, I am a high school senior trying to decide on a career. I am considering computer science as a career, but I don't like Mathematics. Would I have to do a lot of difficult Math like Calculus 1 and 2 to get a computer science degree? | "computer science" as a career is working at a university or research department somewhere and usually requires a masters or PhD. It usually requires good math skills.
The majority of people with a CS degree don't work as computer scientists, but instead go on to be software engineers somewhere. If the question is "is software engineering a good career choice?" Then the answer is yes. It might not earn as much as a doctor, lawyer, finance, but it earns more than most other professions and is a *lot* less stressful than the doctor/lawyer/finance route.
The math load of the course is entirely dependent on the university and syllabus. Whilst you might have to pass a calculus course, you'll almost certainly have to do a lot of discrete math, e.g. graph theory/algorithms and things. | 43 | 17 |
ELI5: What needs to happen for a plane to fly into other countries' airspaces? | When a plane crosses another country's airspace in its journey, what happens? Does that country's air force get all airplane schedules of the day ahead of time and verify that? Or is there a database of planes flying that we don't know about? | If it's playing nicely then it will have a filed a flight plan and be carrying a transponder which identifies it, so air traffic control are expecting it and know which plane it is when it appears on their radar.
If not, and it doesn't respond to air traffic control asking what it's doing, then fighters would be scrambled to go and see what it is, and eventually shoot it down if the appearance of fighters doesn't make the pilot more talkative. | 25 | 38 |
What is the most fascinating emerging field in Philosophy in your opinion? | Probably the most response you get will be problems from bioethics field. New problems in that discipline are just piling up> nanotechnology, artificial intelligence, genetics, cryogenics, etc, etc. Maybe the better question is> what is the most fascinating author or theory. New fields, as subdiscipline of philosophy, are hard to codify. | 21 | 30 |
|
ELI5:Why didi so many black activists in Civil Rights Movement the US convert to Islam? | I see the extra i in did now and I am sorry | In their quest for civil rights and equality, many blacks in American rejected white culture, along with a largely white religion that was content to see them in slavery. Many turned to Islam, a more African religion, in a quest to reconnect with African culture. | 25 | 18 |
ELI5: why does the rest of the Middle East hate Israel? | The two primary reasons are religious differences and the history of how Israel became a (disputed) country. During the time of WW1 and WW2, the areas now known as Israel, Palestine, Lebanon, Jordan, Syria and parts of Egypt were controlled by different powers, starting with the Ottoman Empire (Turkey) and the British. After WW2, artificial borders were drawn up giving Israel an "official" territory. In the following decades, the countries surrounding Israel, at various times, attempted to take over parts of that territory (most notably the 6 Days War in 1967). Those conflicts were largely unsuccessful but had the effect of breeding resentment between Israel and its neighbors. Territorial conflicts with Palestine continue today from the results of the 1967 conflict. Add to that fundamentally opposed religious views and a history of aggressive self-defense (arguably bordering on open aggression) from Israel, plus open extremism from Hamas (terrorist attacks against Israel, etc.), and you get the situation you see today.
*note that the story will vary wildly depending on which side you ask, but this is a fairly neutral overview. | 57 | 124 |
|
ELI5: What do people mean when they say "...because of the economy"? | What exactly are they referring to?
As far as I can tell, the economy isn't doing anything to me that affects my spending decisions/job opportunities, so either I'm totally missing something, or it doesn't apply to me (incredibly unlikely - I'm probably just ignorant). | An economist in the 1700s, Adam Smith coined the term 'The Invisible Hand' to describe the small effects that changes to the economy can have that may not seem to affect you directly.
For example if interest rates go up your company may not be able to borrow money for a new factory this year. If there's no factory you might not get a promotion. With no promotion you don't buy a new car this year. Since you're driving your old car, you might have to bring it to your mechanic more often. With more business from people in that situation, your mechanic hires more staff and builds a second location. | 39 | 34 |
eli5 How did people get iron or other metals in 9th century. Did they extract metals from wherever we do now ? | Mining metals has been known since likely prehistory in many areas. In both Europe and Asia, from about 5000-6000 years ago there were thriving mining operations and trade network for metals.
By the time frame you ask for, Europe and Asia were filled with iron mines and iron would have been traded widely.
Or in short, yup, they mined it.
That said, there were areas that were not mining iron, such as the americas, Australia, the South Pacific, parts of Africa.
If you’re specifically asking if they mine from the exact same deposits we do now, mines eventually go dry or aren’t reasonable to extract more ore, so the answer can be both yes or no depending on the mine, and modern techniques allow us to mine metals in ways that never would have been achieved by earlier people.
Add to that, a lot of the industrial revolutions early start is a result of finding better ways to mine (both coal and metals) which resulted in some early steam powered industrial engines (to pump water out of mines) | 23 | 18 |
|
[Star Trek] What does 'Vulcan' mean to the Vulcans? What is the Vulcan name for themselves and their planet, and how do they feel about being known by a name from Terran mythology? | I mean, take Spock. Does Spock speak English and call himself a Vulcan, or does he use the universal translator which just translates the name of his planet into "Vulcan" in English? Is "Vulcan" the official name for his planet Federation-wide? When he introduces himself to an alien whose species never encountered Vulcans and has no name for Spock's people, does the translator say the English word "Vulcan"? How do the Vulcans react to this Terran linguistic hegemony? | It has to be a mix of universal translators and humans habits of making up names for things other than the actual names.
What do you call this country?
*Nippon*
Im sorry? Did you say Japan?
*No... Nippon*
Well Japan sounds better, youre Japan now | 61 | 34 |
ELI5: Why are directors considered the "masterminds" behind movies? Don't the writers and producers contribute more to the movie's plot and aesthetics? | Writers contribute dialogue, narrative, theme, etc. Producers contribute money, mostly.
Directors, on the other hand, take the input of writers and other creatives working on the film, as well as the talent of the actors themselves, and try to shape that into an artistic expression. They are the ones who can have a broad vision for how a scene might play out and not just *what* is said and done, but *how*.
So while writers, producers, and others have their roles to play in the production, the director is the one person who can (or ought to) bring everything together into one package. | 56 | 61 |
|
Confusion about the definition of socialism | So when I look up the definition of socialism, it says it’s the government controlling the means of production. However, whenever someone is talking about the government redistributing wealth, people say “that’s socialism”. But how is that socialism? Isn’t the definition of socialism just the government basically owning businesses? Wouldn’t wealth redistribution be a different thing, since the government isn’t actually owning the means of production, they’re just taking from one person to give to another? | There is a related concept called "social democracy", which generally advocates for a greater degree of redistribution to help the disadvantaged and government regulation of private businesses. Despite its reformist policies, social democracy supporters generally have no fundamental objections to capitalism--they believe that most of the economy should be capitalist, with redistribution and government regulation to control rent-seeking and lessen the raw harshness of inequality and creative destruction.
Scandinavian countries are particularly famous for their model of social democracy. Other continental European countries, like Germany and Spain, also allude to social democracy in their constitutions. But they are still capitalist--they have no intention of replacing private ownership over the means of production. People from those countries are perplexed when Americans call them socialist, or compare them to the Soviet Union. That's partly due to Americans using the word socialist as a slur.
Further to the left of the social democrats are "democratic socialists", who legitimately believe in the common (i.e. government) ownership of the means of production. As an example, the post-WWII British Labour Party engaged in a massive nationalization program. In addition to welfare programs like pensions and collective bargaining rights, they nationalized industries such as healthcare, energy, transportation, electricity, telecoms and certain banks.
Many of those industries were later privatized, but famously the National Health Service remain to this day -- much of the British healthcare industry is still state-run, like public libraries or police departments in the U.S.
That said, many traditional socialist parties who once believed in actual socialism eventually became social democrats. In that process, they also engaged in the redefinition of "socialism", e.g. the UK Labour Party defining socialism as "*for the many*, *not the few*", which is technically social democracy.
TLDR: technically socialists believe in massive nationalization of industry, social democrats just want more redistribution. But some social democrats and some right wing Americans also use the word socialism to refer to social democracy, so that confuses things. | 63 | 91 |
CMV: Cultural appropriation is not a bad thing | Okay, I really want to change my mind here, because a lot of the people I generally agree with my position here.
Full disclosure, because I think it’s relevant: I am a straight white cis male, but I hope that doesn’t doesn’t deter minority voices. Don’t spare my feelings.
I’m also American so my experience and focus is white people appropriating from non-white people, though I want to talk about the concept in general.
Cultural appropriation, as I understand it, can generally refer to people looking at other cultures and saying “that food/music/clothes etc. is neat, I’ll incorporate it into my life”.
Some people have said it’s wrong for the appropriating culture to use something they don’t understand. Others have said that it doesn’t matter how much the culture is understood, you can’t steal from another’s culture.
This seems like a natural evolution of culture though. A culture changes it’s customs, adding things and removing things as it wants. When the Moors invaded Spain and were eventually kicked back out, the Spanish peasants stole the Moores’ culture of bathing regularly and being more hygienic, as the story goes.
I understand the big difference of power struggle here. The Moors were the invaders, and the Spanish were being colonized. However, I don’t see this argument amounting to anything more than a distaste for white culture.
I also see the fetishization of minorities in America. A lot of white people look at black people as “the ones who make the cool music and talk all cool!” as if they’re not people the way white people are. This plays into the power struggle argument, but I don’t see why white people should be barred from appropriating. | Cultural appropriation is usually meant to describe one of two things: when members of a dominant culture adopt another culture's practice or icon without fully understanding it, and when members of a dominant culture are able to profit off of another culture's practice or icon while people of that other culture have a much harder time.
Do you disagree these things are bad? Just trying to get a lay of the land here. | 15 | 24 |
Why are clouds often discrete? | Especially those stereotypical bunny clouds on a windy day. Are all clouds big enough that each one represents a pocket of air where the conditions for condensation are right? If so why isn't the upper air more uniform?
Are individual clouds sometimes directly from individual lakes, or other smaller isolated geological features? (not mountains or coasts)
I've never really been satisfied with my understanding of cloud formation, but I get the theory (i think). There was a similar question on yahoo answers, but the answer wasn't very helpful for me. | Clouds appear to have a very well defined boundaries because of a property of optics. If you went to a cloud an measured the density of water vapor you would find that at the boundary between the cloud and not cloud changed a little but not a lot. This is because the opacity of air is proportional to exp(density of water vapor), so that a small change in the density of water vapor will lead to a dramatic change in the opacity. If you could go up close to a cloud you would see a small transition region, but from far away it looks like a really sharp transition from transparent to opacity. This is what causes clouds to have their distinct shapes and features. | 38 | 30 |
[Star Wars] Why weren't all the clones as good in combat as Jango and Boba Fett? | Age and experience. The clones were aged at an accelerated rate, and were only between ten and fifteen years old, most times you see them.
Most times you see a Fett, he's had many more years of combat experience.
Plus the Fetts focused on single combat, not squad or army-based tactics. | 175 | 126 |
|
ELI5: How does stretching work? What does it do to the human body? | Stretching improves circulation by increasing blood flow to your muscles. Why most people when they wake up yawn and stretch. It improves circulation helps the body recover faster. Stretching keeps the muscles flexible, strong, and healthy, and we need that flexibility to maintain a range of motion in the joints. Without it, the muscles shorten and become tight. ... Injured muscles may not be strong enough to support the joints, which can lead to joint injury | 10 | 18 |
|
CMV:That cyclists should have to carry ID with them like every other road user. | In Australia we have a debate happening about introducing a law saying cyclists should have to carry ID with them when riding on the road with cars and other licensed vehicles. I don't understand what the pushback is, but it's fierce.
The road is a heavily regulated space, we have laws and rules for conduct on the road and we hold users accountable through licensing laws and consider road use to be a privilege - not a right.
So why do cyclists think this doesn't apply to them when they use the same space?
**EDIT: Ok, my view has been changed. Or rather, clarified. I can now see that carrying Photo ID at all times for all cyclists is a prohibitive measure and does not increase safety nor accountability for cyclists using public roads. However, I do think that on certain busy roads, i.e. - roads over 4 lanes, motorways and highways that cyclists should be required to hold a license and register a roadworthy bicycle. They share a heavily regulated space with other regulated drivers and I don't think it's reasonable to exempt cyclists from these regulations.**
**If you wanna change my edited view - have at it.**
_____
> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | A driver's license fulfills two roles. It serves as a license to drive a car and, as a secondary purpose, it serves as an ID. Drivers are required to carry an license as proof that they have obtained express permission from the government to operate a motor vehicle.
People aren't required to carry a license or ID to occupy a public space. They are only required to carry a license to conduct a regulated activity such as driving (or in the case of James Bond, to kill.) Basically, unless the government has regulated a specific activity, the rights belong to the people. They don't need permission to do it.
Walking or cycling in the street are not regulated activities. There is no licensing course to be a cyclist or pedestrian like there is to be a driver. A child who has never driven a car a day in her life can legally ride her bike down the road.
Unless the government is willing to legislate cycling as a restricted activity, there is no grounds to require cyclists to carry license/ID. But that is a whole another CMV. | 37 | 66 |
Why are Plato's dialogues of Socrates much more famous than Xenophon's? | Basically because they are a lot richer philosophically and as literary works. As well, Plato himself was more influential on the whole philosophical tradition that followed him, and so his importance just sort of snowballed in a way that Xenophon’s works couldn’t keep up with.
But really, the richness of the works is what matters here. Nobody could read Plato’s *Phaedrus*, for example, and think Xenophon holds a candle to that. | 37 | 63 |
|
How do lakes deep underground maintain an ecosystem with no energy input from the Sun? | Underground aquifers could support primitive microbial life-forms if they were adapted to living off the minerals, and hydrogen seeping into the water from the surrounding rock. They may also adapt similarly to deep sea life that lives off of/near hydrothermal vents if they're present in the underground aquifer | 3,200 | 7,501 |
|
What kind of reading schedule do you maintain to be on top of everything while completing a major research project and going through day to day life? | I only ask because I'm a final year undergrad who has gotten by through bursts of productivity on some days and days where I am out of commission. I might read 4 articles/book chapters a week in depth and loads of skimmed material ie. stuff I didn't have time/energy to complete. There is no regularity or sense of control involved. I am always fighting against the clock, my mental health and my ability to get it done.
I hope that understanding the day to day workload of someone undertaking a major research project like a pHD can help me plan out my own routine when I take on my thesis next year. I want to take some control back. I know with my mental health issues, it will always be a struggle but being prepared is what has gotten me this far!
I know answers differ individually! I'm just trying to get a rough idea so I can build towards my own goals little by little. | I suggest setting goals in terms of time spent reading, not the amount read. Spend the same time every day reading, and it quickly becomes part of your routine and you won't have to worry whether you've done it or not. And you can easily scale it up or down to find the ideal balance. | 73 | 126 |
What are some lesser know statistics career options? | I’m going to keep it short and to the point. I’m a college student who enjoys statistics and would like to enter the field after I’m done uni.
From my limited understanding, most jobs are corporate jobs helping the company optimize production or academia. What are some other things you can pursue as statistician? | Marketing, social planning, policing, urban planning, utilities, forensics, auditing .... Any thing that asks Why does this happens ? What will happen ? Can we make it better ? Is this really a problem ? How do we know ? Are we safe ? | 19 | 26 |
Why doesn't the glass inside optic fibers break? | The individual optical glass fibers used in cables are very strong and very flexible because they have a large tensile strength and small diameter. This is the same material used fiberglass boats, ladders, etc.
When bundled together inside a coating, along with strengthening components such as Kevlar, and then wrapped in extra material (the cabling) to protect against dirt, bending, crushing, etc. you have a very tough fiber optic cable.
Having said that, breaks and faults in fiber optic cables are not unheard of. | 57 | 62 |
|
ELI5: How can Jeremy Hunt get away with imposing a new junior dr contract when something like 98% of medical professionals oppose it? | So as I'm sure people in the UK know by now, Jeremy Hunt has decided that negotiations are over and has imposed his new, extremely unpopular contract on junior doctors despite two strikes that have had the support of the majority of the general public.
Is there anything that the general public can actually do when they disagree with something the government is imposing?
| Basically, the legality of contracts are decided by the government and the laws they set. Minimum wage, for example, means that a contract can't be for less than that.
The Government simply changes the laws for contracts that affect junior doctors. Then, the hospitals can't draw up a legal contract if it doesn't adhere to those new terms.
In terms of the general public affecting a change like this, you had your chance in the 2015 election. Welcome to another 5 years of Tory rule. | 47 | 85 |
How does superluminal (ftl) transmission of information or matter violate causality? | I keep reading in threads that hypothetical FTL propositions (wormholes, warp drives, ect) violate causality, but I haven't found an explanation as to why this is so.
| The exact time difference between two events depends on your frame of reference. Two events that happen far apart in time in one frame can happen very close to each other in another frame. All this is governed by Lorentz transformations. Now if an object travels faster than light in one frame, than the Lorentz transformation shows that the object is traveling backwards in time in other reference frames. If an object (or information) can travel backwards in time, that means that a cause in the future can lead to an effect in the past. Cause and effect are therefore backwards and causality has been broken. Breaking causality leads to all sorts of non-physical paradoxes, and therefore is understood to be impossible. Therefore, traveling at faster the speed of light is impossible. | 19 | 44 |
ELI5: Why space vacuum does not suck out our atmosphere? | Atmosphere is just a layer of gas on the surface of the planet. Their composition varies a lot; Venus' is incredibly thick, but Moon's is so sparse that it weights just a few meager tons.
But why does Earth have one? There just was enough gases to form one. Gases are lighter than solids or liquids, so when gas is produced one way or another it starts to climb above the heavier materials.
We _currently_ have an atmosphere because Earth has enough gravity to keep it from floating away and a strong enough magnetic field to keep solar radiation from eating it up. | 18 | 15 |
|
Why does Freud/Psychoanalysis come up a lot in philosophy discussions? | My academic background is cognitive science, and Freud and psychoanalysis were taught to give us some understanding of the roots of psychology. Outside of that, Freud's ideas (and much of psychoanalysis) are not taken seriously by mainstream psychologists. My professors spoke of psychoanalysis as a dying form of therapy, and said very little else.
I'm wondering how Freud is perceived in philosophy given that he seems to come up a lot in this sub and r/philosophy. I'm what contexts his ideas are used in philosophy as well. | Accepting Freudian thought has serious implications for philosophical questions. For example, in the realm of political philosophy, the notion that our actions are determined by specific unconscious drives presents a challenge to other notions, namely the Marxian idea that the economic mode of production is the primary motivator of human action. The 20th century gave us many philosophers and psychologists who were compelled by aspects of both theories (Fromm, Reich, Adorno, Lacan—just to name a few). | 70 | 109 |
ELI5: Why do Americans learn a foreign language so late in their educational career(i.e. high school and college) while foreigners are practically fluent in English by the time they're in their late teens? | And on a related note, why is it that American schools only offer 2 or 3, maybe 4 languages (usually French, Spanish, German and maybe Latin)? | Part of it is that in Europe it's more important to learn other languages because of proximity. Look at Germany France and Belgium. The countries that all have different *majority* languages and they all touch.
In the US we have a one of Canada's provinces to the north that speaks French and then then entire height of our county before you get to Mexico where people speak Spanish. | 49 | 50 |
[Star Wars] Are all sith "evil" or Darth Sidious and his followers were just shitty people who happened to be sith? | The Dark and the Light sides are simply divided by their practitioners' adherence to certain emotions. Where Dark Siders draw from raw emotion: Jealousy, Anger, Fear, etc. Light Siders draw from higher feelings like Patience, Compassion, Mercy.
While one may follow the Dark Side and be "good" (for instance, passionate love is the domain of the Dark Side and that's not necessarily bad), the power drawn from the Dark Side is drawn in large part from very selfish feelings. The greedy, aggressive and megalomaniacal are the strongest in the Dark Side, so those are the ones who managed to become Sith Lords.
TL;DR - Sith are dicks because Sith are powerful in the Dark Side and the Dark Side's power mostly comes from being a dick. However, not all who use the Dark Side are necessarily dicks. | 108 | 97 |
|
ELI5: Why are so many common philosophical ideas dismissed as Philosophy 101? What concepts are covered at higher levels? | Most common philosophical ideas are common because they can be communicated and understood without an extensive background in philosophy or specialized vocabulary. Think of the plot of the matrix and its idea that the reality we perceive may not be 'real' at all, this is a very expansive concept but it's summarized very briefly and most people 'got' it without too much explanation.
These sort of ideas are dismissed as 'philosophy 101' because they may be profound and interesting ideas but anybody with one semester of logic and critical thinking probably already knows and understands them. They're entry-level concepts, and being able to comprehend and discuss them indicates a basic familiarity with philosophy in general, not some deep, arcane knowledge.
The higher levels can encompass nearly anything, so it's hard to be specific. The distinction is more about methodology than the subject matter, it's like the difference between looking at a bug under a dissecting scope in fifth grade vs. looking at it under a scanning electron scope in college. You're investigating the same subjects, but more advanced methodology requires more advanced techniques and more experience,and the results are more informative but also harder to understand. | 20 | 25 |
|
ELI5: How did herbivorous dinosaurs get so large while have so little protein in their diet? | I get that they would have a surplus of vitamins but I don't understand how something as big as the [apatosaurus](http://en.wikipedia.org/wiki/Apatosaurus) could get as big as it is with so little protein. | Part of what allows Herbivores to grow as large as they do is that the Digestive Systems in Herbivores are optimized for extracting every bit of protein available from the food they eat. Their digestive tracts can also make some proteins from food that lack proteins. A good example is a a cow's Digestive Tract: It has four stomachs, all for getting the most nutrient possible out of every bite.
Also, plants aren't necessarily devoid of protein. Plants have Keratin, which most predators, and humans, can't digest. Herbivores however, usually can digest it. This greater diversity to what a Herbivore can eat allows them to have access to a surprising amount of protein and nutrients. | 21 | 23 |
ELI5 Why you must turn your phone to airplane mode on some airlines, while others offer on-flight wifi | WiFi radios can be set at specific frequencies in the 2.4 and 5ghz range, configurable by the access point. This frequency can be tested to not interfere with the plane's systems. Wifi radios generally transmit at less than a watt, and modern planes with internet access are much more likely to have better quality wiring that reduces interference.
With cellular data the radios are stronger because they have to transmit farther, and there is a huge array of frequencies they use: GPRS, Edge, 3G, LTE, etc.
Another factor most don't consider is the wireless phone companies don't want you using your phone during takeoff. At several thousand feet and doing 300mph, you're contacting every cell site in town and bouncing from one to another quickly. The likelihood of completing a quality call or getting decent data speeds is low, and you're using a lot of their resources to do it, so they don't want 150 of you trying.
So the phone companies pushed the FAA to disallow cell phones on commercial airplanes, but got them to cite nebulous safety reasons.
| 25 | 36 |
|
[Three Laws of Robotics]I need my robot to disregard the first law | The kids in my neighborhood have come up with a new way to pass the time: They walk up to someone with a robot, and tell the robot something along the lines of "I'll kill myself if you don't follow me" or "My grandmother is dying, only you can help her!". Essentially they trick the bot into thinking it's in danger of breaking the first law, thereby ignoring any commands it is given, dropping whatever it's doing and running off with the kid. I've even heard of some of them tricking the bots by endangering their own health by eating something they're slightly allergic to.
Sometimes the bots don't come back, In my case it did. How do I stop this from happening again? | You should be able to retrieve your robot's memories, which are admissible as evidence in most jurisdictions. You can sue the kids and their parents in small claims court for monetary compensation if they damage or steal your robot, and if they waste its time you can charge them for its runtime at labor wages.
That said, this is a great example of why the Three Laws are a terrible idea. | 179 | 254 |
CMV: American portion sizes are too big and this is contributing to the society's problems | Compared to the rest of the world, or at least the places I have travelled to, American portion sizes for restaurant-served meals are easily at least 30 percent more than what they are elsewhere, usually even more so.
I feel that this introduces a host of issues:
1. Some people are doggy-bagging the leftover food that is inconvenient to carry around and the extra packaging is bad for the environment.
2. Some people leave the remaining meal which is wasteful.
3. Some people continue to eat the entire meal even when they achieve satiety or eat their required portion halfway through the meal. This pattern causes an abundance of health issues especially as people are mentally-tricked into thinking that it is their own designated portion size, not realizing that a smaller portion might have sufficed or even served them better. The feelings of satiety often take a little while to transmit to our brain and overeating in that window is often harmful for health.
4. The restaurant and fast-food industry profits from serving people larger portions (more sales per customer) which in turn leads to reduced cost per unit of food for the customers and in turn entices more people to turn to unhealthy restaurant/fast-food vs homecooking healthier meals.
I know my post doesn't apply to every person and if you are a younger guy with a high metabolism, you probably think the portion size is adequate at best. I do understand that portion sizes are subjective person-to-person but given how diverse the American population is, with a mix of people of all races, genders and sizes, it might make more sense to keep the portions smaller so a larger number of the population can only order as much as they need to. | For people with less money, a larger portion can be helpful since a larger portion meal can count as two meals, like you said. They may not have the time to make a homecooked meal, so this may be their best option, at times. | 665 | 2,832 |
How do fish know where home is? Do they have a set place in the ocean they always come back to? | How do fish navigate the oceans, and how do they not get lost along their way? Do they have a place in the ocean they would call home and always come back to? | Many organisms have magnetoreceptive organs or organelles that help them sense magnetic fields. These specialized structures have been found in numerous species of fish, birds, molluscs, insects, even bacteria. It is believed that migratory fish use magnetic fields to navigate. | 11 | 34 |
ELI5: Why are elementary schools so much smaller than middle schools, than high schools, etc? | In the area where I live in the US which I'm going to assume is generally emblematic of most areas in the US there are a ton of small elementary schools, often really close to each other, some middle schools, and a handful of high schools across the entire state.
Why are elementary schools made to be small and yet densely packed in an area compared to a high school? | Several factors together:
Little kids tend to need more individual attention (smaller student:teacher ratios), so you need more classes at the elementary level. That means you need more classrooms. You could just stuff them all into one bigger building but...
Little kids don't do as well with long bus/drives, and they can't drive themselves. It's a lot more convenient for middle/high schoolers to walk/bike/drive/bus (far) to school than little kids. So you want the elementary schools close(er) to the students. That means a big number of relatively small buildings spread around, rather than one huge building.
And middle/high schools tend to use much larger/specialized/expensive resources, so you want to concentrate people to make best use of them. You're not going to build a 400m competition track, pool, mid-grate theater, full chemistry lab, machine shop, etc. at every elementary school. | 57 | 23 |
[ELI5] If sound is matter vibrating, and the speed it vibrates is pitch, what dictates volume? Is it the amount of matter vibrating, and if so, does that mean there’s a “max volume” for air? | The energy it carries, which is apparent by the amount of space by which it displaces particles, known as amplitude. I’m not aware if there exists a max volume, but there’s definitely a threshold where it begins to cause damage to things. | 127 | 208 |
|
eli5: How did ancient armies find each other before battles? | EDIT: A little background to the question for people saying scouting (and to clarify why I initially posted). This was my first thought as well, but in reading about Roman history, I’d found out that they were notoriously bad at scouting, as it was something that they felt was below them (and it cost them at Lake Trasimene). Thats when I realized I had no idea how these armies would actually find each other | Terrain and supply lines. Without modern machinery, everything moves by muscle power. It simply isn't possible to move hundreds or thousands of troops, supplies and arms across steep hills and slopes (don't be fooled by what a motorized vehicle can carry and climb - muscle power is very limited)
In that sense, it isn't really possible to disguise where large groups of troops have to march. They follow level terrain where FOOD and WATER is available. (large troops on feet cannot march far in a day, and cannot carry weeks of food/water) Even if horses are available - horses are going to be limited in quantity and most of the support will be carried on carts and backs. | 42 | 46 |
[Mass Effect] How does the Quarian economy work? | They are all secluded on their fleet, their only outsource being labour the labour of youths that leave to travel, and yet they have an acceptable military and their society is stable. What's going on? | The Quarian society is mostly self-sufficient and produces mainly life support goods or spare parts. Since they are known to be expert engineers the majority of production and other functionality is automated. The most widespread job is maintenance which can be performed by people of almost any age due to good planning/interface design.
On the fleet the galactic credits are not used much since everyone is provided with basic supplies (which everyone produces together based on their skills and decisions of ship or fleet authority). Credits' main use is purchasing technology or ships from outside sources. The popular form of trade aboard the ships is barter - exchange of rare imports brought by those on Pilgrimage or hand-crafted cultural items like tapestries. It is not uncommon for vessels to temporary exchange crewmembers for especially tricky engineering or social cases.
The military favors those who successfully completed their Pilgrimage as the most experienced ones while the rest are still allowed to take on lesser roles.
-- excerpts from research by Council Space Relations Analyisis Group, noncommercial
| 16 | 15 |
When two waves destructively interfere, where does the energy go? | Destructive interference occurs either at some moment of time or at some point in space. In time, if two waves meet each other and
destructively interfere, then a few moments later they will have traveled some additional distance and will constructively interfere. In space, if two waves produce a dark spot at some point then there will be a bright spot at a different point. The energy canceled out by destructive interference is always compensated by the energy doubled up from constructive interference.
EDIT: There seems to be some confusion as to how this works. The superposition cos(kx + vt) + cos(kx + vt + pi) = 0 represents two waves propagating in the same direction which cancel everywhere, which is a trivial solution to the wave equation. It means nothing was emitted in the first place. If you reverse the propagation direction of one of them, they will not cancel everywhere. This is what is meant by interference.
EDIT 2: The reason this probably seems surprising is because wave interference is usually taught by considering only the spatial variables for simplicity. Using only spatial dependence means you have selected one particular moment in time. But apart from the trivial solution discussed above, *total destructive interference cannot occur at all positions at all times*. And this is the whole point of the question. If waves could simply disappear, energy would not be conserved.
EDIT 3: sin(kx - vt) + sin(kx + vt + c) = 2sin(kx + c/2)cos(vt + c/2), where c is the phase shift. | 31 | 112 |
|
CMV: Just because I’m a white American doesn’t mean I’m a colonizer | I was in a Facebook argument about something completely unrelated and someone called me a colonizer. I mean, just because my ancestors stole and colonized land doesn’t mean im a colonizer, does it? My reasoning is that I never colonized land. I was born in an already colonized country and I live in my parents home. I haven’t stolen land from people. I reside in stolen land and benefit from American colonization, but does that make me a colonizer? Wouldn’t that mean basically everyone in every country is a colonizer? I mean, there were people in America before native Americans (I think, correct me if I’m wrong please), so then by that logic wouldn’t native Americans also be colonizers?
I guess you might compare this to white privilege. Yes because I benefit from the systems put in place to protect white people, and I get all the other benefits I get for being white, that absolutely means I have white privilege. Yes I have a “colonization” privilege, but is it true that since I benefit from that, then I’m a colonizer?
Just because my ancestors owned slaves and I benefit from the centuries of slavery, does that mean I’m a slave owner? Perhaps this is an invalid comparison, if so please tell me why.
Perhaps my perception of what a colonizer is in incorrect?
Edit: in my opinion, a colonizer would be someone who has literally stolen or colonized land from another. The difference for me is that I live on stolen land, but I didn’t steal it myself.
Edit 2: Based on what other commenters said, I’m taking the word colonizer too literally, it was probably just an angry insult. But regardless, the point they were probably trying to make was that I benefit from colonization privilege, which I agree. | I would suggest taking a more nuanced view. There are many other people around the world that would consider the US to be colonizers right now. You (and me) benefit greatly from extracting cheap resources from third world countries. It’s not exactly the same but there are enough similarities that it would be fair to consider what the US does as a modern form of colonialism. | 34 | 40 |
When listening to the radio in a traveling vehicle and then going through a tunnel, and the audio of the song/news turns to static, what is being played through the radio if the signal is lost, as in, what provides the 'static' sound? | Thank you everyone for all the informative responses. Much obliged :) | For radio signals to be received correctly, with few errors, the signal to noise ratio (SNR) should be above a certain threshold. The SNR can lowered by decreasing the signal strength (which the tunnel causes) or increasing the noise. For analog signals (AM/FM) as the signal strength drops the quality of the signal becomes worse, which we hear as the static noise drowning out the FM station.
The static you hear (especially at FM frequencies) is mostly made from radio frequency interference (RFI) from the electronics all around us (eg, motors, power supplies, computers). Any electrical device can, and may, produce some amount of radio noise. There is also a thermal noise floor of the radio receiver which limits its sensitivity (but RFI will generally be the stronger interference) and even noise from space (see CMB). All these sources of noise add up to create what we usually call white noise (its the same as the “snow” on an analog TV).
An analogy of white noise is people in a crowd. If you are in the middle of a crowd and everyone is talking you wont be able to pick out any particular conversion but there will be a lot of noise. if someone picks up a megaphone and starts talking into that, you will be able to hear that person above all the background noise (even if the volume of background noise doesn’t change).
​
You can us visualize the radio spectrum with a device called a software defined radio (SDR) and the cheap ones can be picked up for less than $20 (RTL-SDR). | 1,106 | 2,850 |
How does one read information from qubits? | When the qubits are being read by the outside world, they would collapse - how do we make sure they collapse so that the information is accurate? | This is the entire challenge of creating quantum algorithms, and there's no set method. The way that you manipulate your qubits will vary depending on what sort of problem you're solving. The basic idea, though, is that since quantum states can interfere with each other, you arrange it so that states corresponding to correct answers constructively interfere, while states corresponding to incorrect answers destructively interfere.
The simplest quantum algorithm is probably the Deutsch-Josza algorithm, which solves the following problem: Given a function that takes as its argument a string of 1s and 0s of length n and outputs either a 1 or a 0, and given that this function is either a) constant, meaning it gives the same result for all inputs, or b) balanced, meaning it returns a 1 for exactly half the possible inputs and 0 for the others, how can you tell which of a) or b) is correct?
The solution is essentially to take n qubits, in a superposition of all possible states, and manipulate them so that any state that returns a 1 picks up a negative phase shift, while any state that returns a 0 is unchanged. If the function is balanced, then the half of the states with a negative phase shift will exactly cancel out with the other half that are unchanged, whereas if it's constant, all states have the same phase and so all reinforce, and this is set up to be linked to the probability of measuring a particular state, where all the qubits are 0, in the output. So you measure the output, and if you get all 0s, then you know it's constant, and if you get anything else, you know it's balanced.
This is a simplification, but it should give at least a sense of how it works. | 21 | 33 |
ELI5:What are the different programming languages for? | I only know that HTML and CSS are for webpages but completely clueless about the rest. Can they all be used for web pages? Or do they each do a different thing? | In general all programming languages can all do the exact same thing. They differ in how easy, how fast and how efficient the process of doing the thing is.
The basic test for what a programming language can do is to see if it can do the same thing as a very simple computer called a "Turing machine" and language or system that can do that is called "Turing Complete". A language that is Turing Complete could do any computation task given an infinite amount of time and memory. This turns out to be a very low bar, for example people have built a turing complete computer inside of Minecraft.
Once that low bar is out of the way the languages begin to differentiate.
Some languages like Python are super easy to learn, but run really really slow. This allows you to focus on making you algorithm really good, but makes it nearly impossible to fiddle with the nuts and bolts of how the program is run.
Some languages like C are more difficult to learn but run really fast. Alot of the old operating systems were coded in C, because they really need it going quickly.
Some language like Java or C++ strike a balance in between them.
Other languages like MATLAB focus on doing one thing and doing it really really fast and easy, but are difficult for other thing. MATLAB does math and graphs really really well, but you would have to jump through some serious hoops to build a game out of it.
Also the languages differ in the "Libraries" that support it. A libary is a collection of code that a programmer can call upon to help him do something. For example rather than writing the code to draw a cube on the screen from scratch, he downloads a library and calls the function in the library to do it for him. | 16 | 20 |
ELI5: how does the inflation works? How come everything costs more than 50 years ago? | Governments try to run monetary policy so that there is a small but consistent level of inflation, achieved through a combination of controlling interest rates at the central bank and issuing money through raising government debt.
They do this because a small level of inflation encourages investment and encourages people and companies to take out loans to invest, thus moving money around the economy.
Too high inflation starts to impact day to day lives through rapidly falling wages.
Deflation tends to be very bad - when money grows in value on its own, and when the real value of outstanding debt increases, and when goods will cost less tomorrow than they do today, then the net effect is that everyone who can stops spending money, which pulls even more money out of the system, which causes further deflation while pushing up unemployment. It’s a spiral that’s very hard to get out of. | 19 | 21 |
|
[ELI5] What exactly is a mushroom? How do they differ from plants or animals? And what makes some safe for human consumption? | A mushroom is the fruiting body of some types of fungus. The reason the fungus living in the soil underground or in a rotting log grows them is to distribute spores which are like mushroom versions of seeds.
Fungus are an entirely separate branch of life from plants and animals.
Some of them develop a poison which can kill people who eat them. Some don't. Producing a poison takes extra energy, so ones that don't probably developed in areas where there were less animals likely to eat them. | 106 | 140 |
|
What is python for? | So, I have a rough understanding of computer programming. I was into it like 15 years ago, but got distracted by life. But for the life of me, I can't understand what python is for or why it's so valuable.
What do you do with it? I'm familiar with like machine code, or robotics programming with like C# or something like that, or M-Code...
Java (I think) is for making gui's, html is for making the functional linking of pages and elements... But what is python for?
I'd love a reason to learn it, but I won't buy a tool I don't know how to use. | So, Python (just like Java or C#) can be used for a lot of things including Ml/Data Science, Webapps (Django, Flask) or even GUIs. It is a dynamically typed language and is actually much slower than C but has some other advantages over it. It is easier to learn and you don't really have to buy it. | 22 | 25 |
ELI5: What is the benefit of having a stuffy nose when sick? | We get stuffy noses when our nose gets inflamed inside. But what is the point of this inflammation when we are sick? Is there any benefit to it? It only seems like its there to annoy us and make breathing a hard time. | Inflammation/ mucus help keep more foreign matter/ antigens from entering your body. When you are under attack from an antigen, your immune system responds by upping the amount of mucus to keep out any more antigens. This way your immune system is not overwhelmed. So, although it is uncomfortable, it is an important part of your innate immune system. | 106 | 450 |
CMV: While gender can be decided upon by the person, sex cannot due to genetics and sex, not gender, should be used for medical and other information on forms (as well as gender if necessary) | Gender, especially because of people who identify as transsexuals, can be chosen since they are male/female but identify as the other. For example, a XY who identifies as female is a MTF trans and vice versa.
That being said, sex is biologically deterministic and dependant on the appearance of the Y chromosome. Even if you have multiple chromosomes, such as XXY, or deficient, such as X0, the Y chromosome determines sex and therefore, anatomy. [To this date, there are no functioning uteri in MTF transexuals](http://en.wikipedia.org/wiki/Transgender_pregnancy) and FTM transexuals *can possibly* get pregnant.
Especially from a medical standpoint (and one striving for medical school), I don't want to (in the future) determine that the patient is possibly having a spontaneous abortion when all it turns out to be is a ruptured appendectomy (both emergencies, but diagnosis wise completely different).
Forms, especially medical ones, and other ID should have your biological sex on it, instead of gender to prevent such confusion. CMV.
**EDIT:** If gender is used, it should be used only for statistical purposes, like in censuses, or for the person's own beliefs and views.
**EDIT1:** I've acknowledged that all ID, as well as only X/Y sex-based determination is too broad/narrow and should be used in less cases/include more information.
_____
> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | I will give you medical forms listing biological sex since it's legitimately important to know (although some people are intersex biologically).
But what's the case for it in any other context? You say other ID should also have it, but the only examples you give are medical. Why does the cop who pulls someone over need to know what kind of genitalia / chromosomes they have? | 154 | 441 |
Is it a contradiction to be a pro-choice vegan? | I became a vegan because I realized I couldn't justify causing unnecessary suffering for sentient beings, or those beings likely or possibly sentient but without clear evidence for being so (benefit of the doubt, as it were).
However, in the case of pro-life vs pro-choice, I sense a certain amount of cognitive dissonance in myself. If I'm giving the benefit of the doubt regarding sentience to animals like chickens and fish, what's to say that an unborn fetus doesn't at some level achieve similar levels of sentience? And, with a lack of understanding of fetal neural development and inability to draw a line, the pro-life position seems to be the least at odds with the reasoning that led me to veganism.
It's especially concerning to me, since I used to justify being pro-choice with exactly the same logic: that a fetus likely has less or equal sentience/awareness than animals we eat for food, and eating animals for food is ethical, therefor abortion is ethical. I now reject the second premise.
EDIT: I should add that I'm vegan in the sense of The Vegan Society's definition:
>Veganism is a way of living which seeks to exclude, as far as is possible and practicable, all forms of exploitation of, and cruelty to, animals for food, clothing or any other purpose. | Jeremy Bentham wrote in the 18th Century:
>A full-grown horse or dog, is beyond comparison a more rational, as well as a more conversable animal, than an infant of a day or a week or even a month, old.
There are perfectly rational reasons to put the interests of many animals above that of a human fetus. There are also much more serious consequences to bringing an unwanted child into the world relative to the consequences of not eating animals (in fact not eating animals has even more positive consequences).
There is plenty of room to be pro-choice and vegan. The only hypocrites are the people who claim to be pro-life without being vegan. | 27 | 29 |
Why are there shadows in electron microscopy? How are they different from shadows due to the absence of light? | I just watched [this gif of a moving drill recorded with an electron microscope](http://i.imgur.com/BMU4Wx0.gifv) and noticed that there are both shadows and gloss where you'd expect them if it was made with a regular light capturing camera.
Are these effects identical with shadows and gloss due to light (or the lack thereof) and if not, how are they different? Are there any differences in size, strength, specularity etc.? Is there an effect similar to iridescence?
Or is this part of post-processing? In my research field, there are several examples of scientifical visualisations that create faux shadows in order to simulate spatiality, but to the best of my knowledge, electron microscopy isn't one of these technologies. | There are two main types of detector for imaging on an SEM. Backscatter electron and secondary electron detection.
Backscatter electrons are the 'reflected' electrons that have scattered of atomic nucleus, the chance that an electron will backscatter is a function of the atomic mass, i.e. areas with higher average atomic mass appear brighter. In terms of shadows etc. Backscatter electrons behave in a similar way to light, in that they are the 'reflected' electrons. This causes shadows to behave the same as it would in light.
Secondary electrons are quite different, and you need to be cautious in interpreting secondary electron images as you would a light image. The primary electron beam penetrates some distance into the material surface, scattering about, think of this causing a teardrop shaped volume under the material surface where there are ionising primary electrons in high concentration. These primary electrons cause low energy secondary electrons to be emitted. The secondary electron detector detects these low energy elections by using a low voltage electric field that isn't strong enough to effect the high energy primary and backscatter electrons. Because these secondary electrons are created in a teardrop volume under the surface, where the primary beam strikes near and edge or slope, some of that teardrop is exposed to the chamber, causing a much larger proportion of secondary electrons to escape and be detected. Additional, these low energy electrons follow a curved path causing odd illumination effects.
In essence, both modes can have shadows and glare, and these can be deceptively similar to light imaging, however, as in the secondary electron image you showed, the glare is likely caused by the angle of the surface and the shadow by the tool piece blocking the path to the secondary electron detector rather than indicating the source of illumination. | 453 | 2,062 |
ELI5: Why is Iowa so important in presidential elections? | / | As stated elsewhere, it is first, so it is important. People vote for winners, so if you are winning early, people are more likely to get behind you. And there are a lot of benefits to doing it this way. With so much money involved nowadays, arguably a candidate with less money has a chance if he/she can win over enough people in a smaller state like Iowa. If it was in California, New York, etc, you would have to have a ton of money to make a dent in reaching that size of a population. | 15 | 28 |
ELI5: What is the difference between PGP keys, SSH keys, and SSL keys? | I know that they all use asymmetric encryption, but I don't understand their differences and applications. Any guidance is much appreciated! | The only difference is the types of programs they're used for (PGP usually for email or encrypted messages, SSH usually for securing remote connection to computers, SSL usually for running a website or anything else done over SSL), but besides that they're the same keys just wrapped in a different container. | 47 | 101 |
CMV: Writing is more persuasive when we vocalise it (say it out loud) first. | A curse on business and academic writing is the Myth of Professionalism. This is the belief that to sound like we know what we’re talking about we have to use formal, abstract, high-register language, ie long, fancy words derived from Latin and Greek (think ‘construct’ instead of ‘build’, ‘depart’ vs ‘leave’, ‘request’ vs ‘ask’). High-register language is solemn, emotionless and soulless. I think it makes writing sound more drone than human; it alienates readers and kills personality.
Instead, I think any piece of persuasive writing has more impact (ie clearer, more readable and livelier) when you vocalise what you’re trying to say and use that as your first draft.
There are three reasons I think vocalisation works:
1. Because we use normal, mid-register language (aka ‘plain English’) when we vocalise, as opposed to formal, fancy language, it makes us sound more human and more approachable. So it helps tone of voice.
2. For the same reason, it helps us clarify our message; we immediately know when something sounds clear and when it doesn’t. It makes our writing clearer.
3. Mid-register language has more emotional energy than high-register language. It gives our writing more energy.
Change my view. | Interesting topic. A couple of clarifying questions, if you will?
1) How about a non-native speaker, who has learned most of their vocabulary and diction from books and movies (rendering it vastly different from what you refer to as "mid-register language")? Can they not be as persuasive, even if their writing is clear and concise?
2) Why do you think vocalization would be the solution, and not something different, e.g. a diagram of interconnected ideas, a list of bullet-points?
3) Why would "more (emotional) energy" make the text more persuasive? Wouldn't the text then constitute an appeal to emotion more than an appeal to logic? What if the concepts being communicated rely on logic more than emotion? Should you not make the text fit the idea, rather than the other way around? | 32 | 172 |
ELI5: Why is it often political suicide to "flip-flop" or change one's opinion based on sound argument, evidence, or voter opinion? | It seems like every election cycle this is a negative phrase used by one candidate to the other (both sides being guilty of this). I can think of several times that my personal opinion has been swayed by sound argument, evidence, or strong social movements that I would otherwise not be aware of.
Thus, changing a political ideology or belief seems like a good thing as it would appear the individual is: a.) listening to arguments and building a sound opinion; b.) listening to the voices of the people and representing the population; c.) has new information on a topic that sways his/her opinion on previous established beliefs. All of these reasons seem to give a person a unique perspective of both sides and allows for civil discussion and debate to continue to occur. Why is this seen as such a negative thing to voters? | There are a few aspects to this. First is that people like politicians with strong internal principles that they agree with. Bernie, for example, has been hammering the same points for 30 years. You can find old clips on YouTube from the 90s that are almost identical to his campaign speeches. Having strong principles is a selling point.
As a corollary, the worry with politicians changing their mind is that it means they can change their mind about anything for any reason. And there are a lot of bad reasons out there. How do people know you weighed the evidence and came to a reasonable conclusion when you could have just as easily been given a lot of money by a lobbyist or realized there were a few thousand votes to be gotten for a small policy shift?
It's a fine line. We want politicians that can be swayed by new evidence, but we don't want ones that will cave to anything resembling pressure. But since it's easy to make an ad about flip flopping and hard to convince people that you really did change based on evidence, this is what we get. | 12 | 15 |
How would Galileo (in his time) convince people of the accuracy of his telescope? | How things look through a telescope is not evidence to convince people to switch to the Copernican model unless people believe exactly what they see? Galileo could have fiddled with the device so that people see an image he wants them to see. How did he convince people that his instrument was so accurate that it was worth the paradigm shift to move to the Copernican model? Surely some strong indicative reasoning is required there that did not exist yet? | You should try reading his short text “The Starry Messenger” in which he instructs the reader on how to build his device, describes what he sees and posits about the heavenly body, and then asks the reader to confirm and continue his work. | 45 | 40 |
ELI5: How are doctors trained to deal with hypochondriacs and patients that are especially anxious about their health? Do they end up getting worse care than more ordinary patients? | Generally, you try to avoid giving in to unnecessary tests. And you try to build a rapport with them as best you can so that they will trust you when you say that nothing is wrong with them. Ask questions like “why do you think you have X?” And then explain why that symptom doesn’t mean you have X disease | 22 | 25 |
|
CMV: The US national wait list of organs for transplant should provide "extra waiting list points" to patients with a history of being registered donors. | There are currently over 115,000 Americans awaiting a life saving organ transplant and about 8,000 of them die each year while waiting. Organs are now allocated by the national wait list computer based on things such as time waiting, acuity of illness, blood type, time/proximity to donor and body size. The wait list algorithm should be changed to include "organ donor registration status" as an important allocation variable, meaning adults with a history (five or more years) of donor registration will be moved to the top of the list and those who have refused to register as donors moved toward the bottom of the list. This will tend to remove the "free rider" problem, give incentive to more people to register which will lead to more transplants and more lives saved.
Pediatric patients under 18 will not be part of this extra point system. Patients between the ages of 18 to 23 will be provided a portion of extra wait list points dependent on the percent of time since turning 18 that they were registered i.e. a patient listed for transplant at age of 22 and registered as a donor when they were 20 would get 50% of bonus points.
_____
> *This is a footnote from the CMV moderators. We'd like to remind you of a couple of things. Firstly, please* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | Some states have automatic & easy registration, for example as part of getting a drivers' license. Other states do not. Your proposal would punish sick people for the crime of being from the wrong state.
Even in states with that kind of automatic registration, your proposal might punish people for not having a drivers' license. | 13 | 28 |
Does it mean anything if professors at a university got their PhD at that same university? | Im looking at engineering PhD programs \(US universities\) and notice at one university in particular that several professors \(at least 5\) within the department got their PhD from that same department. Three of them even all had the same PhD advisor. They range from early career to mid\-late career \(30 to 50 years old\). It is well known US university ranked in the top\-10 for many areas of engineering.
Some people have told me this is a bad sign. Is it? why or why not? | It's not necessarily a bad sign, but usually the feeling is that an academic should leave their graduate institution for the next steps in their career for a few reasons:
* Exposure to other philosophies at other institutions, broadening one's experiences.
* Flip side of this, the department usually wants to bring in people from other institutions to benefit from their different perspective learned at their previous department.
* To spread the prestige of the graduate institution (not always a factor, but some people care about this).
* Probably the big one is to spread out collaborator networks and more importantly funding. If you have several professors at a university working in the same area as their advisor, that can make it more difficult to bring in funding - either you have multiple separate teams competing in the same field, or you have fewer external collaborators to strengthen a multiple-PI proposal (especially if you haven't gone beyond your first university to build a network). You may also see higher competition for grad students with several professors working in such closely-related areas.
* There can sometimes be an issue with nepotism if several of these faculty have the same advisor who is a very senior member of the department. Even if they're not a department head, that advisor may have an excess of political power in the department due to having essentially lackeys to back them up.
All that said, these are just benefits from leaving your graduate institution (except the last factor) - it's not a *bad* thing to stay put, if you like the location for living in (a very underrated factor!) or the institution is a completely premiere location for your kind of research and simply the best option. Alternatively, some professors will have moved around a few times, e.g. after earning a PhD, someone might do a postdoc somewhere, go into industry for a while, spend a few years at a national lab, and then return to their first institution as a faculty member. So it may not mean anything, but if you see other warning flags it could be a bad sign in combination with those. | 42 | 25 |
ELI5: why is the color green the magic color for video editing? | The idea is to have a color which is unique to the background or a portion of the image which is to be removed or altered. Blue is another color commonly used but red is avoided because humans tend to be somewhat pink in our fleshy bits which could be confused for the screen.
Another benefit of using green is that many digital image sensors have more green subpixels than blue or red. This is because the human eye is most able to detect differences in shades of green so maximizing fidelity in that range yields a better image. But this also means that cameras effectively have a higher resolution for the color green so a mask made using that color can be better than with a different color. | 94 | 31 |
|
how does light polarisation with a third filter at 45 degrees allows light to pass through? | I understand how polarisation works but don't understand how adding the third filter to pass through, please help! Thanks :) | The key thing with polarisation filters is that once the light has passed through, it is now *all* polarised in the direction of the filter. So you start with randomly polarised light, and it hits filter 1(vertical). Now 50% of it passes through, and is now all polarised vertical. If it now hits filter 2 (horizontal) 0% gets through, as the filter is at 90 degrees to the incoming light.
If you add a third filter at 45 degrees in the middle, then after filter 1 the light now hits a filter at 45 degrees to vertical. This lets 50% of the light through, which is now polarised 45 degrees from vertical. Now when it hits the last filter there is another 45 degree difference, so another 50% of the light gets through (Three 50% losses means we are now at 1/8 the starting light!).
Does that make sense? :) | 73 | 316 |
[Rampage]Why did George Just get bigger, but stay otherwise the same? | why didn't his body develop new defenses/adaptations (IE like the Wolf's gliding ability, or the Alligator's armored back spikes)? | It seems to effect different animals in interesting ways. It also seemed to make the other two much larger. It might be a safety built into the serum. The closer an animal is to human the less dramatic the effect. His albino genetics might have resisted the gene editing. | 10 | 19 |
ELI5: How does tax evasion by large multinationals work? | I hear a lot about large multinationals (Apple, Google, but also Panasonic etc) setting up their 'headquarters' in a country that has relatively low tax rates. How precisely does this work though and how come they don't have to pay tax in other countries if they've also 'set up shop' there? | Take a coffee company who buys coffee in country A then it is placed into a small bags in country B and then sold in country C. Now any profits the company makes can be taxed in country A, B or C, now for most companies this would normally be country C, however if the company sets up sub divisions of its company in country A B and C and if country B has a very low tax rate it may do some sneaky accounting. Division A buys coffee and sells it on to division B without making a profit, division B then sells the newly packaged coffee to division C at a huge profit, division C sells the coffee to the public without making a profit.
The company then pays minimal tax in country B and no tax in countries A and C and has successfully evaded tax. | 13 | 15 |
Moving to a new country for a PhD - scared it will ruin my relationship. | So, im assuming this is a common problem, feel free to link any previous threads dealing w this. As young reseacher (ecology n conservation) it's super hard to get a funded position. But now, I might be able to get one in Germany. Moving there is plausible for me, the city is great and the topic is right up my alley. In my heart I feel that this is something I want for myself. The problem is Im (practically) married to my long-term partner. I'm simply scared of putting us through long-distance hell. But I'm also scared of the prospect of having him going there with me and ending up miserable through lack of work and connections. Ruining this great relationship for a job would be too tragic, and not the correct priority. So - huge conflict of interests!
Experience with this? How have you solved your family issues when getting far-away job offers? Have you moved for the sake of your partner's career?
Edit: I should specify that I'm in Scandinavia now, so I would be located about a 2 hr flight away. Still far but not the same situation as a cross-atlantic distance! | Examine your relationship, ask yourself do you see a long term thing with this person. If so, you must make the distance a temporary thing. Do not leave it open ended. Meaning, one of you should plan to move to be close to the other.
Also, make sure you have SCHEDULED visits. Don’t just see each other when you “can” or “have time.” Be intentional in your planning. I’m a psychologist at uni and this is a huge concern among grad students. You can work it out long distance provided your intentional. | 70 | 32 |
CMV: The United States two party system is an illusion of democracy and basically the closest you can get to dictatorship without a dictator | I so often hear Americans declare the United States the greatest democracy on earth and get confused. How can a system where you only get to choose from two real alternatives be anything but an illusory democracy? Sure, you might get differences if Republicans or Democrats are in office, but whoever has power only have to collaborate with one other party IF they have a minority in in either chamber. Otherwise all they have to do is convince themselves to votes for a proposal.
Coming from a country where we have more than 10 different political parties and only 6 million people, I feel like Americans are in denial that they in fact do not live in a true democracy. Having more than 10 parties representing everything from environmentalists, communists to libertarians and pure capitalist nationalist might be tedious, but parties actually have to corporate to make sure all peoples voices are heard, to get a majority.
EDIT: I am reading replies and trying to answer all, although a lot certainly was posted while I slept. | Why focus on just the federal government? On a day to day basis, state and local governments affect peoples lives much more significantly. In that regard - there are many more political parties and positions at issue.
I also think you’re discounting how much variety there is in just the two parties. Joe Manchin and Ocasio-Cortez are in the same party, but there’s a fair bit of distance between the two in terms of their political positions. Democrats and republicans get primaried all the time as voters choose a more moderate or extreme candidate. | 413 | 2,299 |
ELI5: Why do healing wounds feel warmer to the touch? | When you're injured, your body inflames the area around it - basically by increasing bloodflow to that area. This allows the body to move lots of platelets to the area (to scab it over), lots of white blood cells (to fight infections), and to help repair the area and remove damaged bits.
So all the increased bloodflow to that area makes it warmer. If the warmth continues for too long, it's a sign that the area could be infected, in which case the body is still pumping white blood cells to that area and keeping up the heat to fight off the infection. | 12 | 16 |
|
The Conspiracy Against the Human Race - Influences? | I began reading the book this morning and... it's a bit verbose for me. I'm very curious as to what works Ligotti may have picked his ideas up from in hopes that they may be easier to digest. | I’d advise patience. Ligotti isn’t an academic philosopher, but he is a fine prose stylist.
He also highlights a number of different philosophers and philosophical works in the footnotes as you proceed through the book’s pages. The most important source for him is a relatively obscure essay called “The Last Messiah” by Peter Wessel Zapffe, a pessimistic Norwegian philosopher. You can find a copy of that essay online. | 20 | 29 |
cmv: Culture Appropriation is not a crime and should not be taken as seriously by people on the internet. | As per my understanding, culture appropriation means adoption of certain aspects of foreign cultures which may or may not be for profit.
Whenever a celebrity makes an attempt to utilise characteristics of a culture that is not theirs, I often notice people bringing up 'culture appropriation'.
I don't understand this. There are million other points you could use to speak against a lot of celebrities but this one does not make any sense to me.
CULTURES ARE MEANT TO MIX. THEY ARE MEANT TO INTERMINGLE AND BRING FORTH NEW CULTURES.
When you mention the words 'culture appropriation' in English, you're calling out the appropriation by SPEAKING THE LITERAL KING OF APPROPRIATING OTHER LANGUAGES. There is little to nothing in the english language that is 'english' per se but that's completely fine.
It is necessary for cultures to interact, take the best aspects of each other and utilitise them. That's how cultures grow. That's how everything grows, im pretty sure that's how genetic variation in animals works as well.
So by saying that something is 'appropriating' another culture, you're cutting cultures off from one another and in a way gate keeping certain things from the global society.
I hope I've worded my points well enough and would love to be proved wrong:)
go off, r/changemyview | There’s a difference between partaking in/spreading a culture and appropriating a culture.
Take Native American headdresses as an example. There are countless traditions and customs associated with them. Disregarding all of the history and just wearing one as a Halloween costume is whats considered appropriation.
Taking a cultures fashion (that has a history/ritual associated with it) and rebranding it as “exotic fashion” is cultural appropriation. If you go to a cultural celebration with a friend and they offer you something to wear, put it on. They’re offering to share their culture with you. | 20 | 130 |
Is it possible that exposing deep-sea creatures to bright LED lights, like we do in wildlife documentaries, could be harmful to them or to their biomes? | There is always a risk of exposure or harm in exploration. In this case, it should be a minimum, temporary disruption since it it just light. The benefits of learning about that biome and its creatures is outweighed by the possible temporary harm. | 15 | 19 |
|
ELI5: What do lost ants do when moved away from their colony? | Everyday, a lot of ants are moved away from their colony because of human interaction (for example, ants which are on human objects). What do those lost ants do? | Well ants have a special thing called pheromones, which are basically a unique substance that they can put out to convey messages to others of their colony such as “food” or “danger”. This is why you often see ants moving in long single file lines, because they are following the pheromone trail. As more workers use the trail they reinforce it and it becomes more predominant, but to answer your question, a lot of times if they are displaced they’ll be able to pick up on a pheromone trail after wandering around (workers move pretty far to get food), but if they can’t find a pheromone trail and rejoin the colony they’ll probably die. | 27 | 26 |
ELI5: What is a "firing solution"? | In regards to missiles and torpedoes, what exactly do they mean when they are working on a firing solution. Especially when most modern missiles and torpedoes seem to have automatic homing / target funding technology? | Firing a torpedo involves three or more factors while attempting to maintain stealth.
The directions and speed of the ships, the current, and possibly terrain, means that shooting a torpedo is a tricky bit of math especially when the other ships position speed and such may not be known perfectly.
On top of that, while torpedoes CAN use sonar, the later it goes into active hunting mode the better chance to hit the target so the goal is a shot with a course that maximizes the chance of putting the fish in striking range and minimizing the chance to the enemy escaping it. | 30 | 15 |
Are there any legitimate medical conditions that make it difficult to lose weight, even on very low calorie diets? Doesn't that violate the laws of physics? | There are many, many cases when people have no idea how much they actually do eat. Or, when they do, they are not honest.
That being said, it is possible that the individual is honest. In that case, there are a number of variables:
Not everyone absorbs nutrients at the same level of efficiency. Some people absorb better than others.
Not everyone has their basal metabolism at the same level. Some people burn more calories while resting, others burn less. This remains true even for people weighing the same. It depends on the body composition, age, gender, fitness, various medical conditions, etc.
A young, muscular, lean, fit man will burn a lot of calories just sitting down. An old, fat, out of shape woman will burn much less - even though she weighs the same weight like the young male athlete.
The same young, muscular athlete will burn more or less calories while sitting down, depending on the levels of thyroid hormones in his body - this is just one example out of so many.
EDIT: The nice little charts you see online, that tell you how many calories you're supposed to burn, based on weight and age, are just guidelines. There are many, many other factors that are pretty important. | 12 | 24 |
|
ELI5: how and by what means can the origin of the poison be determined, example from the recent poisoning in UK where they know it came from Russia? | Certain details of the manufacturing process leave detectable impurities in the chemical. If you have samples to compare them to, you can determine with decent accuracy what lab they came from. The same sort of technique is used in drug investigations.
Also, particular ingelredients may be local - as someone else mentioned - making it possible to determine origin.
Edit: however, those sorts of things only tell you where it was *made.* Russia has, at times since the end of the Cold War, been a *bit* careless with their military stockpile. Presumably, this is why the Brits gave their unanswered 'deadline for explanation.' as opportunity for the Russians to explain the possible black-market movement of the chemical.
They may also have other types of evidence, intercepted communications or some cool spy shit, that indicate direct Russian involvement. | 20 | 22 |
|
ELI5: Why does sunburnt skin feel warm to the touch? | Your body opens up capillaries in the burn area and flushes blood there as part of the healing process. Redness and warmth to the touch of sunburnt skin is caused by there just being more blood than usual in the area. | 205 | 279 |
|
[Fiction] So, really, are 'universes' and 'dimensions' two different things? If so, then why people get them mixed up when it comes to the multiverse? | The reason I ask this, is because for the longest now, I've always assumed that 'universe' and 'dimension' are the same thing but are said differently, when talking about characters travelling through the multiverse in fictional stories.
However, apparently, from what I've heard, universe and dimension are actually two different things with different meanings behind them (I can't exactly remember what the meanings are, so if anyone knows, answers would be very nice, thank you). So, if that's the case, if a universe and a dimension are not the same thing, then why is that characters in fiction (or writers of said fiction) get them two things mixed up like they are the same thing? Are different dimensions something that's located within the same universe, or is it just writers not knowing the differences between them? I'm honestly confused, really.
If you know the answer, please provide with some explanations or reasons behind it. Thanks. | When the two terms are used distinctly, a universe usually contains dimensions. Dimensions are essentially different planes or pockets of reality within a singular creation, that singular creation and all that it contains being called a “universe”. | 44 | 38 |
Why are pokemon starters always Fire/Water/Grass? | Fire, Water and Grass are all useful types to the budding trainer.
**Fire** is great for camping and outdoorsy people. Fire types can really assist the young trainer by allowing them a free source of warmth, fire and a (generally) powerful, loyal companion.
**Water** types are normally brilliant companions, due to their water-producing abilities. Water is the basis of human biology and life, and as result a free water source is invaluable to those setting out on an adventure. Water types are also useful in that they can ferry the trainer across (sometimes vast) expanses of water.
**Grass** Pokemon are useful friends to have, as any trainer that finds themselves without a shelter for the night may find themselves staying in the (manipulated by their Grass Pokemon) trunk of a tree, or they might seek shelter in a cocoon of branches and leaves. Grass Pokemon are natural creatures of the forests, and as a result will be invaluable in gathering berries and other natural food for the adventuring trainer.
All three type are useful in their own way, and are naturally strong for battles. | 44 | 39 |
|
What causes seeds to germinate only when inside the soil, but not when inside the fruit? | Plant growth regulators. When those stop(fruit rots and breaks down) those stop and the seed can germinate if in moist condition. I’ve had multiple apples, tomato’s, and peppers actually have germinated seeds inside somehow so that process can get messed up occasionally. | 22 | 26 |
|
[General Fantasy] There are widely available potions that can cure major injuries. Does this mean minor medical issues like headaches, allergies, or the common cold have been eliminated? Would a standard health potion cure my migraine? | One thing to note is that while healing potions often feel inexpensive to adventurers, they are very expensive in terms of the average commoner. They do work for a wide variety of common illness and injury, but often are economically out of reach for most folks. | 21 | 20 |
|
ELI5: How does your body seem to sober up in an instant if something bad happens? | Your body has a good setup in order to respond to emergencies. It pumps you full of adrenaline and endorphins and stuff like that, and that *can* mitigate intoxication.
But the keyword here is "seem". You are very likely still impaired. | 28 | 21 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.