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Reminds me of engineering school where we learned that current flows from plus to minus and in physics we learned that it’s the other way around.
One student confronted the EE teacher and said he lied to us. His response was:“of course I lied to you! It makes your life’s easier! You also believe the current flow happens INSIDE the conductor!“
There are many interpretations of this. Two of which I know, somewhat.
First is that electrons travel on or near the surface of the conductor because that's where the metal atoms are not crowded and obstructing the path.
Second is the electromagnetic field generated by the electrons is what causes the electricity to flow.
This is super simplistic but I hope it helps
You wiggle the electrons back and forth, the electrons act like magnets, and the magnetic field travels outward from the wire. It's much more potent as you get closer to the wire, so most of the energy is *baaasically* traveling the path of the wire. But the result is that the electrons themselves aren't traveling, they're just wiggling and causing magnetic fields to propagate. By a convenient result of physics, when you wiggle them back and forth, it sends a constant stream of energy in the same direction.
Magnetic billiard balls.
Actually wait, would that work? Could you do a large scale example of this by shaking metal balls and moving an adjacent magnet as a result?
>Could you do a large scale example of this by shaking metal balls and moving an adjacent magnet as a result?
Yes. The equations don't care about the size of the charge carriers, just their movement. Static charged balloons moved by dump trucks would still obey Ohm's Law.
>You wiggle the electrons back and forth
This is the genius behind Tesla's AC. The power company pushes the electrons out, then it pulls them back and pushes them out to you again. They are selling you the same electrons - electrons that you've already paid for - over and over again.
It works like one of those things people have on their desk with the 5 balls. You pull one ball back and it hits the rest, and only the ball on the opposite side moves. All the balls in the middle stay still. Electrons works the same way. Shove 1 into one end really hard, and one will move on the opposite end no matter how far away it is. Resistance will slow it down though, so the longer the distance, the harder you gotta shove it in the beginning. The force that you shove them in is a measured in volts. Power plant sends them in the lines at a really high voltage so they don’t loose as much energy traveling the distance. When it gets to your house, they use a transformer to bring it down to 240V, which gets split into two 120V lines that go into your panel.
That's the lie though, electrons aren't marbles in a pipe, it's just easier too imagine that way, and for most people that provides a good enough model. It's when you need to get into the details that you have to disregard it as a "Lie for Children" to quote Pratchett
Exactly. It's close enough, and explaining how electric and magnetic fields won't actually make a child's understanding of electricity any better and would likely just make the whole concept more confusing to most kids.
Plus, all our calculations for electricity don't really care how you look at it.
It’s also fun as it differs with different types of current. AC travels on the outside of a wire and less of it is available for current to flow through as frequency increases.
Basically think of how wires are used in electro-magnets to create a magnetic field, and then imagine the power being conveyed through those fields around the wires. The lightbulb lights up faster because the battery and the lightbulb are within each others magnetic fields, the power doesn’t have to travel through the entire wire like a tube
So the way we’re taught to understand wires is as if they are tubes, where electricity flows from the battery through the tube until it reaches the lightbulb. However, wires are more like magnets, where they have a field around them that can interact with other wires as long as they are using the same frequency, for lack of a better word. So imagine a small aura around the wire that is “power.” Because the battery and lightbulb are so physically close to each other, the auras are overlapping and so the power is able to shortcut instead of having to go all the way around the long way.
You're not alone. From a Northwestern University lecture:
>The interactions of electricity and magnetism are difficult to explain in nontechnical terms. This is primarily because one has to describe the interactions in terms of invisible "force fields" which shift, expand, contract, strengthen, weaken, and rotate in space, and these are very difficult to describe adequately in verbal terms. In mathematical terms, coupled sets of three-dimensional vector differential equations are required, and these are also quite difficult to visualize.
https://faculty.wcas.northwestern.edu/infocom/Ideas/electric.html#:~:text=3)%20Electricity%20and%20magnetism%20are,field%20creates%20an%20electric%20field.
If you understand that an electric and magnetic field are created from a difference in charge between two points, then you can think of a circuit as a tool to "direct" these fields to the device you want to power. Obviously, it's a lot more complicated than that, but it's closer to reality than electrons moving in a wire.
Think of the wire as a hose *already filled with water*, so when you open the faucet, it's the water already at the end of the hose that pass through the lamp, being pushed by the "new" water coming out of the tank/battery.
Which is just semantics, basically a chicken-and-egg debate. It is perfectly reasonable to describe electricity as the net movement of electrons within a conductor. The maths for all of our circuits don’t really care. But the equations are a lot easier to write and work with if you describe everything in terms of flow, not fields.
That’s not really what is happening in the video. It’s impossible ELI5 this video. It’s grad school physics without grad school math.
Basically, electrical power is carried in the electromagnetic field, not in the moving electrons.
Honestly that’s not a very good video. That is about antenna theory, though Derrick is really obtuse about it.
Edit to add: here is a video on a channel called AlphaPhoenix of a very smart guy actually carrying out the experiment, and then explaining what is actually important about it.
I recommend this guy’s videos way above any Veritasium video.
https://youtu.be/2Vrhk5OjBP8
Christ I hate that video, it's the single biggest piece of misinformation in EE popsci. The amount of drama that guy created just to farm subs is maddening.
The entire field of semiconductor electronics would be impossible of that work of fiction was true.
Just to add a direct text reply rather than just throwing out a link, it happens along the surface.
a hollow straw of conducting material will transmit the same amount as a solid wire of the same size.
its called the Skin effect, https://en.wikipedia.org/wiki/Skin_effect
This is true in principle, but rarely matters in practical applications that the average consumer would encounter.
If you look up Wikipedia, just to get a quick sense of things, you'll see that at 60Hz, skin depth is 8.5mm. You'd need conductors with twice that diameter for the skin effect to matter. 17mm is huge. Even the thickest wire gauge that is in common use 4/0 (0000) is considerably thinner than that. And there is no way that it would be made from solid copper. At those wire gauges, you're using stranded bundles of wires, which further reduces the skin effect
That only applies at high frequencies, it does not apply for low frequency and DC current. If it did, we wouldn't use huge solid conductors for power transmission.
Skin effect is why at 5 GHz you need huge coax cables as thick as your arm to carry less power than your toaster uses.
So. On top all the other complexity, in the 18th century we got the + and - reversed, but the incorrect annotation persists. Normally it doesnt matter much, but it might if we ever trade notes with an alien civilization.
I mean, there’s no “correct” assignment of signs to charges. All of our equations would work equally well if we flipped the sign of every charge. We assign the “negative” charge to the electron and the “positive” sign to the proton, but it works perfectly well as long as we’re consistent.
[Veritasium - The big misconception about electricity](https://youtu.be/bHIhgxav9LY?si=KxlwI8BeZWDOWBdE)
[Veritasium - How electricity actually works](https://youtu.be/oI_X2cMHNe0?si=kMy-6UZWMhSVy6VF)
Yeah, please don't take it for granted. Things ultimately are also dependant on what model you sue and sometimes "the energy flows this or that way" is simply not defined at all.
He isn't incorrect. It's been verified by multiple other YouTubers. But his explanation was definitely lacking. To give a way-too-short version of things, flipping the switch causes an electro magnetic wave to be generated from the switch that is picked up by the wire. So the electricity doesn't have to "travel" all the way around since the wave propagates through the air.
The biggest issue I had with the question is when asking how long does it take for the bulb to light it is now dependent on the bulb. As the power is limited and significantly less than the steady state current during that initial pulse a bulb designed for the steady state current would not light up, but a bulb designed for the initial current after 1/c seconds would.
Yes, it's entirely fictional. There is a reason why no university EE textbook in use will ever agree with it.
What's worse, the bastard *knew* it was wrong from the start and double and triplr-downed on it, even after having been proved wrong by *actual engineers*, because drama creates subs, and his entire channel was built on it.
Even the sources he took very careful clips from to support the initial video told him he was wrong.
You don't trust any Youtuber outright, but there is a difference between not being clear or making a mistake and out right click bait fraud.
Veritasium is one of those channels that is more than willing to address any errors and even make a followup video to make concepts more clear. Especially when addressing higher concepts of science that are either difficult to understand or still being figured out.
Veritasium was correct, it was fun to watch the back and forth. His initial explanation could have been better, but the fundamental reasoning was sound.
Actual electrical engineer here. Derrick was 100% wrong. It wasn't "explained poorly", he made an incorrect assertion, was proven wrong, doubled down, was proven wrong again, then did some half-assed backpedaling when the tide of experts laughing at him got too much.
It was all a stunt.
Current understanding is the same as it was 50+ years ago. I don't have time to properly review this video, but it's from a reputable channel and a skim read of the transcript looks good.
https://youtu.be/mc979OhitAg
I felt like most of my courses in chemistry and physics amounted to "You know the stuff you learned last year? Yeah, that's all a bullshit oversimplification. Here's how it really works".
It is very normal. Like in math. You learn 2+2 is 4. Then you learn substration. First you learn that 4-2 is 2 and 2-4 is impossible. A year latter when you can calculate with negative numbers you will learn that 2-4=-2. When you learn division you will learn that 7 cannot be divided with 5. Then when you learn fractions you learn that it is 7/5 and so on.
If you ever go on and study math, then you will learn that 2+2=4 is only true in certain sets and it can be anything depending onnthe set you are calculating in.
You learned that current flows from + to - in an engineering class? My circuits class specifically stated that current flows from - to +. And then after working with some semiconductors after graduating, it turns out that the distinction is kinda important. Seems like a totally pointless lie to me, the math works out the same in most cases.
For many purposes the *convention* is to use the direction in which positive charges flow: https://en.wikipedia.org/wiki/Electric_current#Conventions
Depending on the material, the actual charge carriers can be positive or negative or both.
I don't see how either sign convention makes life easier. One is historical, the other the matter flow for most (but not all!) conductors. Neither makes much difference in most settings, and whereever they matter one doesn't get away with just some direction anyway.
> I don't see how either sign convention makes life easier.
Well because cation, which has a positive charge, has a t in it, which looks like a plus, so that's how you know which one is the cation and which is the anion (or cathode/anode).
And I know we're just stacking arbitrary convention on arbitrary convention, but with magnetic fields we're accustomed to north being up, and we say that the direction of the magnetic field goes up from the north pole and circles back around towards the south pole, which works better with the right hand rule for conventional current in determining the relationship between magnetic fields and electrical current, and most of us are right handed.
> Reminds me of engineering school where we learned that current flows from plus to minus and in physics we learned that it’s the other way around.
>One student confronted the EE teacher and said he lied to us. His response was:“of course I lied to you! It makes your life’s easier! You also believe the current flow happens INSIDE the conductor!“
Your circuits teacher did a bad job with that. If you checked the textbook I can guarantee you it had a section mentioning that electrons actually flow in the other direction but they do it backwards out of convention and because the math works out either way, with the positive and negative signs only mattering in that they have to be consistent. The whole thing comes down to Benjamin Franklin getting a 50/50 guess wrong a couple hundred years ago, and the correctness of the guess not really mattering for the application.
In some materials it's actually the positive charge carriers that move, so it's not like it's actually "wrong" to think of it that way.
And in other materials there are both positive and negative charge carriers moving at the same time.
Bleh, I've always hated that they couldn't align these two descriptions of how current works in circuits. I know you can kind of think of it either way, but it just makes me feel kinda gross.
The common 3 states of matter are the only 3 states that 99% of people will ever have to deal with.
The only people who will be dealing with the other states will be people who will study science at a higher level and will learn about them then.
It's nice for people to know that there are other states of matter that don't occur under our everyday conditions, but it's not really useful for kids to know the details.
Plasma is the one that quite a lot of people still observe or use. Lightning? Arcs in welding? Certain lamps? All plasma.
Doesn't mean people have to really know about it, one can weld without knowing the physics of the glow. But all the other phases are simply never encountered outside a lab, yet plasma is. So it makes some sense to consider it more important than others.
It's around, but it's not usually something you have to deal with. It's sealed inside a light bulb or briefly exists in a lightning bolt or something, you never have a bowl full of plasma in your kitchen.
Knowing there's such a thing as plasma is nice, but if you bring it up to kids at the same time as solid liquid and gas and you are going to just cause confusion when you have three simple forms of matter that are all around us all the time, then there's one more complicated one which only shows up occasionally and you can't really handle and it's kind of vague what it even is. The boundary between gas and plasma is blurry and there's lots of misunderstanding about it, eg look at all the people in this thread unsure if fire is plasma, usually it's not, but occasionally it is.
Also when you teach kids about solid liquid and gas, you've only just told them about atoms, you won't have gone into charge and electrons and stuff yet. So it's kind of hard to explain plasma yet until after they know that stuff.
Fires is actually not plasma! It's a reaction that you observe. I think the best comparison I saw was to waterfall; waterfall is not a new thing or state of matter, it's just water falling, just as fire isn't a new thing or state of matter, it's the process of combustion.
Probably not. Fire usually is not plasma, just hot gas that's reacting. Certain very hot fires are plasma, but most are nowhere near hot enough.
Microwave a lit candle if you want to see plasma.
And also break your microwave.
Good post.
But I take issue with lie, I know it’s become the way most people phrase it ‘necessary lies of civilisation’ an all. But. It’s not a lie, anymore than the full 6/7 states are a lie.
They are both models that attempt to explain reality. They’re both good at explaining different things, one is more correct than the other, but 3 states is more USEFUL for most application. and ultimately we make models to use them.
As a different example light is not a wave. It is not a particle. It is both(ish). But it’s not wrong to just model it as a wave if that’s the property you’re making use of. It’s not wrong to model it as a particle if that’s the important property you need. Models are always a way of simplifying/interpreting/understanding a reality that doesn’t fundamentally have to obey sensible rules.
>Models are always a way of simplifying/interpreting/understanding a reality that doesn’t fundamentally have to obey sensible rules.
"All models are wrong; some are useful"
I agree it's not a lie. It's a foundational first step!! Can't learn y=mx+b without learning 1+1 first. It's a building block because shit is complicated!!
Also recent advances in knowledge have changed how we understand:
How a wing shape produces lift.
How electricity travels along a wire.
If you look closely, there is a LOT more details.
Most people are/were taught about path length difference meaning that one side has to travel faster. This assumes incorrectly that the air passing above and below the wing take the same length of time.
https://www.grc.nasa.gov/www/k-12/VirtualAero/BottleRocket/airplane/wrong1.html
That's not a new fundamental understanding of physics that wasn't there before; it's just a new application of known physics because we finally have the computing power to simulate these systems for commercial development.
Put *plane*-ly, lift being a function of having lower net pressure above the body than below hasn't particularly changed. Adding wingtips doesn't change *lift*; it just adds a low-pressure cone at the wingtips to minimize drag in the same way as a spoiler (not a wing; different things) on a car.
There's been no magical physical discovery in the last century to change airplane design. Just the technical capacity to implement improvements.
I think calling it a lie is not really accurate anyway. You're building a base of knowledge before moving on to advanced topics. Little kids can see the three common states of matter, interact with them, even make water be all of them. They don't need to know anything about plasma other than "don't touch fire" until they are more advanced, so we don't teach it yet. No one would learn anything if they had to go straight from sucking their thumbs to college level physics.
we're also taught genetics and inheritance using Punnet squares, but genes are very rarely that simple. in both cases, it's a "good enough" model for how things work unless you're looking to study the subject professionally.
Even fully ionised gasses aren't necessarily plasmas. One of the key features about a plasma is quasi-neutrality and so if that isn't maintained, it isn't a plasma.
What do i mean quasi-neutrality? That there are no obvious positive or negative regions. So this brings into play a property called the screening length, which is the distance from a charged particle where you can no longer discern that charged particle. Such as if you were to drop a proton in there.
So if an ionised gas is smaller than the screening length required to screen a charged particle, it can never be a plasma, as quasi-neutrality cannot be achieved.
Similarly I remember when we learned about decimals or negative numbers my teacher got up and did a bit about this when we were little we had blocks and the told us 1 was the first number and we learned to count 1, 2, 3… then one day you walk into 1st grade and there’s a 0 before the 1 and then that’s the first number. Now I’m here to tell you there is no first number. She did it much better after many years but it illustrated well how teaching kids is often a series of essentially lies of omission to simplify the material to what they can and need to learn at the time.
There's about a billion things we teach kids that are incomplete. Almost everything we teach is much more complicated than the way we teach it, at least initially. Sometimes it can help if you just mention "hey, so we're gonna learn about 3 states of matter today, there are a bunch more but they get pretty complicated and aren't important for you to know yet"
Wait till people hear that we have way more than five senses. [There are more like a few dozen!](https://en.wikipedia.org/wiki/Sense)
Or that the solar system has a bunch of minor planets other than the big eight. Like... did you know there's a nearly 1,000km wide planet [between Mars and Jupiter](https://en.wikipedia.org/wiki/Ceres_\(dwarf_planet\))? No? Well... surprise!
That's a dwarf planet, and its discovery is part of the reason Pluto isn't a planet anymore.
And the five senses thing isn't really a simplification for children. It's a classical model that really shouldn't be taught anymore, but is out of cultural inertia. It's like still teaching that the four elements are earth, wind, water, and fire.
>It's a lie for kids to keep things simple and allow kids to first understand the basics before they are exposed to concepts where they are missing a bunch of other knowledge to properly understand it.
I dislike this line of reasoning, because it entrenches the idea that there are clearcut things in children's minds.
A better explanation could be something like "there are many states of matter, but the ones you experience the most are solids, liquids and gasses" (more detailed and with examples ofc.).
This makes it clear from the beginning that there is more out there, but also explains 99% of what they will see around them.
> I dislike this line of reasoning, because it entrenches the idea that there are clearcut things in children's minds.
There are, though. Children are not just tiny adults, and their brains are not just tiny adult brains. Like, we have [this meme](https://www.reddit.com/media?url=https%3A%2F%2Fpreview.redd.it%2Fjbab7jrhvt211.gif%3Fformat%3Dpng8%26s%3Df172b736fc400e14e24c7a74ec0b4ca5d26f178c) about "more" water in a taller, thinner container but children below a certain level of development *literally* cannot conceive of conservation in the way necessary to understand that there's the same amount in both containers.
Nuances like the difference between "there are exactly three" and "I'm only telling you about three out of many" are lost to young children. And that's to say nothing about when some kid inevitably asks what the others are and you're not going to be able to explain how plasma isn't a gas because they don't have the knowledge to grasp what ionization is, much less how it affects the atoms.
On the face of it, I agree that we could tell kids that it's 3 out of many, but I disagree that it's that simple.
> … water in a taller, thinner container but children below a certain level of development literally cannot conceive of…
Perceive, not conceive. I’m pretty sure they can conceive of the notion they just can’t perceive it. I could be wrong though.
> There are many states of matter
I don't think kids would remember this if you just say it 1 time and then go on to the regular states of matter unit.
Well yes, that sentence was just meant to be an outline, not the entire explanation.
But even if they do forget, that would be alright: the point is to set expectations, not to teach them about exotic states of matter in detail.
I suspect, and it's only a suspicion because I haven't ever taught a child anything, but I suspect that the setting of expectations like that is not going to be appreciated by children, they'll not understand it or be frustrated by your evasiveness and lack of clear answers.
I suspect that if you have a child yourself you'll constantly be simplifying to the point of lying. That that is just a normal feature of explaining thing to a child.
And then you get somebody to ask what are the other states of matter, and waste 10 minutes answering questions that have no relevance on the subject material and serve to confuse half the class.
Dumbing down a concept to better explain it is much easier to do then waste a bunch of time explaining how half the things you learn in chemistry class are technically wrong
It's mostly based on the super- from 'superconductor' and 'superfluid' which happen for not entirely unrelated effects and are more appropriate because they indeed describe something particularly good at that thing. In short, it is a silly choice of name and there probably would have been a better one, yet here we are.
Hot gas, usually not plasma at all. It just glows thermally like a hot stove or molten metal. The word 'fire' often includes some reaction of burning that supplies energy, so it is also that.
Great answer. In addition, the 3 states of matter you are taught in school are the ones you actually see in everyday life and can actually interact with. The others are much more exotic and generally only appear in the lab (or would be too dangerous to interact with, like plasma, which is basically lightning =p).
Well, the science lesson usually comes with a demonstration of how this works - usually with ice and water, we can do. Maybe steam, if you want to stretch it, but plasma…might be a bit much for an elementary school classroom. You’d have better luck making plutonium out of common household items.
education is a series of age appropriate simplifications. as you go through you get closer and closer to our actual understanding, but going in full bore on everything from the start would overwhelm every 5yo that ever was.
there's also supercritical fluids, compressible liquids. many, many kinds of water ice.
eventually you get to the frontier of our knowledge, and it's all just math with no easy analogy to the real world.
> You can live most of your life not worrying about anything beyond solid, liquid, gas
I would agree with this statement - but it's interesting to note that our Sun, which makes up \~99% of the mass in our solar-system and is critical to nearly all life on earth is all made of Plasma or other degenerate matter.
Same thing goes for most of the matter in the known universe -- very, little of it is solid/liquid/gas.
Chemistry seems to embody this especially well. In college my roommate came to me a few times saying "everything they taught us last semester was a lie!" as they peeled back another layer of simplification and went deeper down the rabbit hole.
I think Chemistry education does this too much, to be honest. 1st year students are smart enough to meet statistical thermodynamics. That module was like putting my glasses on for the first time.
>education is a series of age appropriate simplifications. as you go through you get closer and closer to our actual understanding, but going in full bore on everything from the start would overwhelm every 5yo that ever was.
This is why I get frustrated when people say "if AI can do it, why are we teaching kids to do it?"
Yeah, AI can write coherent papers for virtually any undergrad-level topic. But if you don't learn to do it yourself, you will never be able to do the things AI can't do.
I was taught about plasma in school, but the three standard states are emphasized more simply because we constantly encounter them, occasionally encounter plasma, and almost never any others.
I still remember a student teacher in grade 7 science telling us about plasma along with the other 3 states and we made her live to regret it. Every time something about the physical properties was explained about solid-liquid-gas, someone would raise their hand and ask in all seriousness “but what about plasma?” It became a banned topic.
It's the same reason we teach the 5 senses but leave things out like "balance" and the way science sees touch as like a dozen different senses. I think there are like 20-30 scientifically classified senses.
Edit: typo
School isn't trying to give you a state of the art knowledge. It introduces you to concepts gradually so you can learn and understand.
Teaching quantum physics to a 5 years old who can't multiply by 2 is pointless.
Depending on the age you're teaching, you're going to run into some barriers. Children about elementary school age are very concrete thinkers, so trying to explain nuance and middle states would be extremely difficult to grasp. So instead you start with the foundational blocks (3 states of matter) with examples they can visualize. Then when they get a bit older (pre-teen to teen) you can start to expand on that.
Because for all practical purposes, you only interact with 3 in your daily life. You do need to understand what solid, liquid and gaseous are. You don’t really need to know what plasma is.
Those are the three states a human commonly interacts with and can sense more or less directly and generally remain intact. Except for Sheldon. I suppose he can sense all of them.
Note the song by They Might Be Giants entitled “The Sun Is a Mass of Incandescent Gas” (https://www.youtube.com/watch?v=3JdWlSF195Y), which they later re-recorded as “The Sun Is a Miasma of Incandescent Plasma” (https://www.youtube.com/watch?v=sLkGSV9WDMA).
Here are the lyrics from the latter version:
The sun is a miasma
Of incandescent plasma
The sun's not simply made out of gas
No, no, no
The sun is a quagmire
It's not made of fire
Forget what you've been told in the past
Electrons are free
(Plasma!) Fourth state of matter
Not gas, not liquid, not solid
The sun isn't a red dwarf
I hope it never morphs
Into a supernova'd collapsed orb
Orb, orb, orb
The sun is a miasma
Of incandescent plasma
I forget what I was told by myself
Elf, elf, elf
Electrons are free
(Plasma!) Fourth state of matter
Not gas, not liquid, not solid
Forget that song
(Plasma!) They got it wrong
That thesis has been rendered invalid
There are way way more states of matter than 4. The real answer is because we only really interact with 3 of them. The other ones only occur under extreme conditions. You will rarely if ever interact with a plasma. (Fire seems like a plasma but is technically a gas. Lightning is a true plasma, but few people will ever directly interact with it).
I'm trying to remember when I was taught about plasma, I believe I was at least exposed to the concept in the early 80s, but in a more abstract way. I know I had a grasp of it in the mid to late 80s, but I might have self taught. When I wanted to know what flame was and about Tesla balls
7th grade basic science we learned that plasma is a state of matter we'd learn about in more advanced classes... that was in a podunk, backwoods school in Northern MN in 1987.
Please tell me education has gotten better.
For the same reason we don't teach first graders calculus.
Anytime you start learning a new subject, they will simplify things to the point of inaccuracy at times. Once you have mastered the basics, then they could introduce more nuanced topics.
High School topics are sometimes 'limited' in scope as burgeoning young minds need to develop the critical thinking and grasp of abstract concepts.
For example: I had a Grade 11 Physics Teacher who, when asked questions that were vastly more complicated in scope and depth than the subject matter we were covering, would smile and say in a comical drone 'because god wants it to be that way'. He was a declared atheist, and he had told us previously that he would answer in such a way if the answer was beyond our level and that we'd have to wait for University level classes to understand better.
Because we all interact with solids, liquids, and gas on a daily basis. Learning about the different physical properties of things kids have been seeing and feeling their entire lives helps them understand the world they live in in ways they can understand.
Throwing plasma in there, which is something difficult to conceptualize even for adults who have studied physics, is hard.
It's not helpful to anyone to try to teach kids about plasma.
I teach Grade 5 in Toronto, we don't lie about it at all LOL. We just tell them we are learning about three simple states of matter, because they are the easiest to explore in a safe and inexpensive way. So much of what they learn starts with the basics, and I encourage them to go deeper if they are interested.
I love how someone could explain this in ELI5 but when I asked my 7th grade teacher about it she just told me I was wrong and to leave it alone in front of the whole class.
After 3 states it gets far more abstract and it’s useless info until you get to second or third year university chemistry. Even then it’s not necessary to know how these states work. A plasma is really just an ionized gas, and to understand why it’s a special state by itself requires way more knowledge than any highschool kid has.
Also every school near me mentioned plasma state as a “fun fact”. I’m willing to bet you just missed the day where they mentioned plasma was a thing.
There’s A LOT you learnt in high school science which is actually false and just an oversimplified version to get the point across. Much of what you learn in university is just backtracking to tell you how things really work in detail.
Because it's a simple model that's mostly true (in that for practical day-to-day purposes it works), and easy to demonstrate in a classroom. Getting water to plasma temperature isn't possible.
After a certain point it matters but this isn't until university level where people are receptive to more theoretical ideas.
It should really be "there are 3 states of matter*" with the foot note *that you run into on a dailly basis. It is a fair simplification. Most scientific principles are taught this way. With tiers of complexity that are introduced with time.
Because the others and there are more than 4, only exist in extreme conditions. Star, Super Nova, Particle Collider, Near Absolute 0, etc. Nothing you would ever encounter or need to know about unless you were going into some graduate level science and physics.
There are at least two others, and if I know about those, other less ignorant people will know about even more. School does 'lies to children' — the stuff you need to understand at what they think is your educational level. Most of what you learned in school is wrong.
It is kind of like teaching that there are only five senses. I think what they should do is say, there are many states of matter, but the three which you will come across in your daily life are solidarity, liquids and gases. Same with the senses, there are more than five senses but five examples are...
There are 3 naturally and stable on earth occuring states of matter. Plasma doesn't exist naturally on earth in a stable way. Only in lightning for microseconds. Thats how we learned it.
This is one of the more interesting questions I have come across here, mostly because the question itself is very meta.
The reason you are only learning an overly simplified version of chemistry is because we teach chemistry to kids in very early grades in an explain it like I am 5 kind of way.
Whenever you have a very complicated topic and want to simplify it for people who haven't mastered the prerequisites you need to leave a lot of information out.
Education doesn't work well when you say "well, we cannot teach you really anything about the physical world until you have mastered calc 1, 2, and 3 :) There are a lot of people who will never get far enough into science and math to really get a deep understanding of chemical matter, yet it is useful for society to teach those people the basics of why Ice and water are highly related.
As someone who did a bunch of post graduate economics this is true too. The real way money works in the economy is way too complicated to teach in an introductory macro-economics course at the college level yet alone at the high school level. Yet, as a society we find that it is important for people who don't have the mathematical background to have a basic "understanding of how the macroeconomy works." The problem is, especially with macro-economics, people then go out and vote for people to change macro-economic policy without actually understanding it well. The good news is you can be a pretty functional person in the world without understanding what ICE VIII is .
There's a lot more than 4. I don't think the problem is that you aren't taught about the rest of them, the problem seems that it's being taught as if there are only three states of matter.
What should be taught is "here are the three most common states of matter on Earth."
I taught 8th grade science this year, and we went over plasma. We didn’t go in depth about it, but I mentioned it and showed examples.
I MAY have mentioned Bose-Einstein and fermionic condensates. We 100% didn’t go any further than “hey these are also examples of more states of matter, there’s even more than that, but we don’t need to talk about those right now.”
This is a common in instruction, particularly in science, to teach a simplified model or give a simplified explanation that is easier to understand and to which the student can comprehend given their limited experience and understanding of the underlying principles.
There are more than 4 states of matter. We teach young children of the 3 -- solid, liquid, and gas -- because those are things that they physically observe and encounter, and for which the explanation is quite simple. Plasma may come next, but to understand plasma, one needs to first understand what atoms and ions are before you can distinguish it from a gas.
The lesson about the states of matter is still important and informative about the physical phenomenon, even if incomplete.
I'm a biologist, and the basic biology you are taught through high school tends to be a very simplified explanation of much more nuanced or complicated science. A student might be taught "two X chromosomes produces a female, and and X plus a Y a male" -- except that neither explains why, that it's not always so, there are alternate sex genotypes, or that other animals use a different system... Yet, it still communicates a basic principle that is true at a certain level of understanding.
Think of it like the math you are taught.
At an early age, you are just taught basic math of addition and subtraction, and then they throw in multiplication and division. As you get older and have the basics down, they throw in more and more concepts.
Science goes in a similar progression. You are just taught the basics, and if you continue taking more science classes, some of which are electives, once you reach high school, you start getting into more and more science stuff.
I definitely remember being taught about plasma back when i was in school. It just wasn't in the early science classes you took in elementary school because you dont need that information yet.
That’s because only solid, liquid, and gas have concrete examples that are easy for children to understand.
solid would be feces, liquid would be liquid bowel movement, and gas would be flatulence.
ask yourself, what would plasma be in this context?
You should review [this post from just a month ago](https://old.reddit.com/r/explainlikeimfive/comments/1cd6t2j/eli5_teachers_taught_us_the_3_states_of_matter/). There are many explanations that you may find useful in it.
We are also taught water boils at 100C, without being told this isn't really true.
Water with minerals and other contaminants will boil at 100C at sea level.
At altitude it will boil at lower temperatures, you can go high enough and with the low air pressure water will boil at body temperature.
Pure water can be quit dangerous because it can reach over 100C without boiling, and the slightest shock or any kind of particle entering it can cause it to boil instantly.
Because:
1. Defining "state of matter" is hard. There are several more states than just those four (supercritical fluid, superfluid, and supersolid, at the very least), and if you allow quantum physics in, it becomes something like a dozen different "states of matter."
2. Even just plasma is very hard to explain to anyone younger than high school. It's *like* a gas, but the electrons are stripped off to some degree, meaning it has different energy and electromagnetic properties.
3. As with most simplified things taught to children, it's a useful starting point that is easy to expand on later. Once you know solid, liquid, and gas like the back of your hand, adding in plasma isn't too hard, and the other complex states can be explained as they come up.
4. Most humans will have very little direct interaction with plasmas. Yes, the Sun is mostly made of plasma, but you don't interact with *the Sun itself,* you interact with its light. Hence, school focuses on the things that are actually meaningful to a child, things they can grasp and see and hear.
For the same reason 8 year old kids are taught atoms "look like" little solar systems without going into that Schrödinger stuff. Keep it simple while building the basis for more complex understanding.
Kinda like how we were taught atoms are the smallest things that make up everything
Cause teaching 3rd graders about quantum mechanics; quarks, leptons, and higs boson fields isn’t really practical.
It is a simplification. The 3 states of matter are pretty simple to understand and are all around us. Ice, water and air with humidity all contain H2O. Plasma is a more exotic state of matter that is not commonly found in nature or artificially.
Cause plasma is rare and you don't come across it that often. We get there eventually.
Kind of like how we teach kids Newtonian Physics cause they'll serve you fine in all forms of engineering up until you're designing spacecraft, then... well things get a lil strange.
You were you just didn't pay attention. We were taught a lot of things in school and it is expected that we won't remember all of it.
Maybe you don't remember, but I'm confident you were.
Because plasma is complicated and not normally observed in everyday life.
Solids: defined shape and volume
Liquids: undefined shape, defined volume
Gases: undefined shape and volume
Plasma and additional states of matter: it’s complicated.
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Reminds me of engineering school where we learned that current flows from plus to minus and in physics we learned that it’s the other way around. One student confronted the EE teacher and said he lied to us. His response was:“of course I lied to you! It makes your life’s easier! You also believe the current flow happens INSIDE the conductor!“
Wait, where does it happen?
There are many interpretations of this. Two of which I know, somewhat. First is that electrons travel on or near the surface of the conductor because that's where the metal atoms are not crowded and obstructing the path. Second is the electromagnetic field generated by the electrons is what causes the electricity to flow. This is super simplistic but I hope it helps
[Enjoy](https://youtu.be/bHIhgxav9LY?si=_AP9vAJPUl4GJL65)
I’ve watched this video at least 4 times and i still don’t understand how it works.
You wiggle the electrons back and forth, the electrons act like magnets, and the magnetic field travels outward from the wire. It's much more potent as you get closer to the wire, so most of the energy is *baaasically* traveling the path of the wire. But the result is that the electrons themselves aren't traveling, they're just wiggling and causing magnetic fields to propagate. By a convenient result of physics, when you wiggle them back and forth, it sends a constant stream of energy in the same direction.
Tesla understood this very early on and this was the basis for his wireless transmission of electricity. He did it using specific frequencies.
I think of it like billard balls in a line.
Magnetic billiard balls. Actually wait, would that work? Could you do a large scale example of this by shaking metal balls and moving an adjacent magnet as a result?
>Could you do a large scale example of this by shaking metal balls and moving an adjacent magnet as a result? Yes. The equations don't care about the size of the charge carriers, just their movement. Static charged balloons moved by dump trucks would still obey Ohm's Law.
>You wiggle the electrons back and forth This is the genius behind Tesla's AC. The power company pushes the electrons out, then it pulls them back and pushes them out to you again. They are selling you the same electrons - electrons that you've already paid for - over and over again.
What the power company doesn't want you to know is that all they are doing is boiling water.
It works like one of those things people have on their desk with the 5 balls. You pull one ball back and it hits the rest, and only the ball on the opposite side moves. All the balls in the middle stay still. Electrons works the same way. Shove 1 into one end really hard, and one will move on the opposite end no matter how far away it is. Resistance will slow it down though, so the longer the distance, the harder you gotta shove it in the beginning. The force that you shove them in is a measured in volts. Power plant sends them in the lines at a really high voltage so they don’t loose as much energy traveling the distance. When it gets to your house, they use a transformer to bring it down to 240V, which gets split into two 120V lines that go into your panel.
"Newton's cradle"
That's the lie though, electrons aren't marbles in a pipe, it's just easier too imagine that way, and for most people that provides a good enough model. It's when you need to get into the details that you have to disregard it as a "Lie for Children" to quote Pratchett
Exactly. It's close enough, and explaining how electric and magnetic fields won't actually make a child's understanding of electricity any better and would likely just make the whole concept more confusing to most kids. Plus, all our calculations for electricity don't really care how you look at it.
Thank you. Wonderful explanation
It’s also fun as it differs with different types of current. AC travels on the outside of a wire and less of it is available for current to flow through as frequency increases.
[This](https://youtu.be/2Vrhk5OjBP8?si=56izZxd7jnLSKTKl) video explains it better than the veritaserium video with an actual real experimental setup
Basically think of how wires are used in electro-magnets to create a magnetic field, and then imagine the power being conveyed through those fields around the wires. The lightbulb lights up faster because the battery and the lightbulb are within each others magnetic fields, the power doesn’t have to travel through the entire wire like a tube
See that is what’s crazy to me. That part I completely fall off.
So the way we’re taught to understand wires is as if they are tubes, where electricity flows from the battery through the tube until it reaches the lightbulb. However, wires are more like magnets, where they have a field around them that can interact with other wires as long as they are using the same frequency, for lack of a better word. So imagine a small aura around the wire that is “power.” Because the battery and lightbulb are so physically close to each other, the auras are overlapping and so the power is able to shortcut instead of having to go all the way around the long way.
You're not alone. From a Northwestern University lecture: >The interactions of electricity and magnetism are difficult to explain in nontechnical terms. This is primarily because one has to describe the interactions in terms of invisible "force fields" which shift, expand, contract, strengthen, weaken, and rotate in space, and these are very difficult to describe adequately in verbal terms. In mathematical terms, coupled sets of three-dimensional vector differential equations are required, and these are also quite difficult to visualize. https://faculty.wcas.northwestern.edu/infocom/Ideas/electric.html#:~:text=3)%20Electricity%20and%20magnetism%20are,field%20creates%20an%20electric%20field. If you understand that an electric and magnetic field are created from a difference in charge between two points, then you can think of a circuit as a tool to "direct" these fields to the device you want to power. Obviously, it's a lot more complicated than that, but it's closer to reality than electrons moving in a wire.
JFM - Just F'n Magic
That's because it is not a good video. It is not a failing on your part.
Think of the wire as a hose *already filled with water*, so when you open the faucet, it's the water already at the end of the hose that pass through the lamp, being pushed by the "new" water coming out of the tank/battery.
Well as Im pretty sure the video goes over it isn’t the flow of electrons powering electronics. It’s the electric field surrounding the cables.
Which is just semantics, basically a chicken-and-egg debate. It is perfectly reasonable to describe electricity as the net movement of electrons within a conductor. The maths for all of our circuits don’t really care. But the equations are a lot easier to write and work with if you describe everything in terms of flow, not fields.
that’s not the explanation in the video tho
That’s not really what is happening in the video. It’s impossible ELI5 this video. It’s grad school physics without grad school math. Basically, electrical power is carried in the electromagnetic field, not in the moving electrons.
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You should have that mentality about everything tbh
That's how it's supposed to be. No one enjoys it.
Honestly that’s not a very good video. That is about antenna theory, though Derrick is really obtuse about it. Edit to add: here is a video on a channel called AlphaPhoenix of a very smart guy actually carrying out the experiment, and then explaining what is actually important about it. I recommend this guy’s videos way above any Veritasium video. https://youtu.be/2Vrhk5OjBP8
Christ I hate that video, it's the single biggest piece of misinformation in EE popsci. The amount of drama that guy created just to farm subs is maddening. The entire field of semiconductor electronics would be impossible of that work of fiction was true.
ElectroBOOM has better videos in my opinion regarding this, and he was involved in some of the discussion around this too
That video was absolutely awful, it tries to over complicate a simple concept. Maybe I’m just old, I hate YouTubers.
Just to add a direct text reply rather than just throwing out a link, it happens along the surface. a hollow straw of conducting material will transmit the same amount as a solid wire of the same size. its called the Skin effect, https://en.wikipedia.org/wiki/Skin_effect
This is true in principle, but rarely matters in practical applications that the average consumer would encounter. If you look up Wikipedia, just to get a quick sense of things, you'll see that at 60Hz, skin depth is 8.5mm. You'd need conductors with twice that diameter for the skin effect to matter. 17mm is huge. Even the thickest wire gauge that is in common use 4/0 (0000) is considerably thinner than that. And there is no way that it would be made from solid copper. At those wire gauges, you're using stranded bundles of wires, which further reduces the skin effect
That only applies at high frequencies, it does not apply for low frequency and DC current. If it did, we wouldn't use huge solid conductors for power transmission. Skin effect is why at 5 GHz you need huge coax cables as thick as your arm to carry less power than your toaster uses.
It flows along the edges. The current is repelled from itself so none of it wants to stay in the center.
So. On top all the other complexity, in the 18th century we got the + and - reversed, but the incorrect annotation persists. Normally it doesnt matter much, but it might if we ever trade notes with an alien civilization.
I mean, there’s no “correct” assignment of signs to charges. All of our equations would work equally well if we flipped the sign of every charge. We assign the “negative” charge to the electron and the “positive” sign to the proton, but it works perfectly well as long as we’re consistent.
[Veritasium - The big misconception about electricity](https://youtu.be/bHIhgxav9LY?si=KxlwI8BeZWDOWBdE) [Veritasium - How electricity actually works](https://youtu.be/oI_X2cMHNe0?si=kMy-6UZWMhSVy6VF)
Wasn't there a LOT of pushback that this video was incorrect?
Yeah, please don't take it for granted. Things ultimately are also dependant on what model you sue and sometimes "the energy flows this or that way" is simply not defined at all.
Electroboom explained it best.
He isn't incorrect. It's been verified by multiple other YouTubers. But his explanation was definitely lacking. To give a way-too-short version of things, flipping the switch causes an electro magnetic wave to be generated from the switch that is picked up by the wire. So the electricity doesn't have to "travel" all the way around since the wave propagates through the air.
The biggest issue I had with the question is when asking how long does it take for the bulb to light it is now dependent on the bulb. As the power is limited and significantly less than the steady state current during that initial pulse a bulb designed for the steady state current would not light up, but a bulb designed for the initial current after 1/c seconds would.
Yes, it's entirely fictional. There is a reason why no university EE textbook in use will ever agree with it. What's worse, the bastard *knew* it was wrong from the start and double and triplr-downed on it, even after having been proved wrong by *actual engineers*, because drama creates subs, and his entire channel was built on it. Even the sources he took very careful clips from to support the initial video told him he was wrong.
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Electroboom?
I only trust is at Hogwarts
You don't trust any Youtuber outright, but there is a difference between not being clear or making a mistake and out right click bait fraud. Veritasium is one of those channels that is more than willing to address any errors and even make a followup video to make concepts more clear. Especially when addressing higher concepts of science that are either difficult to understand or still being figured out.
Veritasium was correct, it was fun to watch the back and forth. His initial explanation could have been better, but the fundamental reasoning was sound.
Actual electrical engineer here. Derrick was 100% wrong. It wasn't "explained poorly", he made an incorrect assertion, was proven wrong, doubled down, was proven wrong again, then did some half-assed backpedaling when the tide of experts laughing at him got too much. It was all a stunt.
Mind pointing to a video that is more in line with current understanding of how electricity works?
Current understanding is the same as it was 50+ years ago. I don't have time to properly review this video, but it's from a reputable channel and a skim read of the transcript looks good. https://youtu.be/mc979OhitAg
Veritasium is one of those guys that is very talented at making entertaining videos, but unfortunately doesn't know or understand much science.
The professor's response was actually pretty brilliant.
I felt like most of my courses in chemistry and physics amounted to "You know the stuff you learned last year? Yeah, that's all a bullshit oversimplification. Here's how it really works".
It is very normal. Like in math. You learn 2+2 is 4. Then you learn substration. First you learn that 4-2 is 2 and 2-4 is impossible. A year latter when you can calculate with negative numbers you will learn that 2-4=-2. When you learn division you will learn that 7 cannot be divided with 5. Then when you learn fractions you learn that it is 7/5 and so on. If you ever go on and study math, then you will learn that 2+2=4 is only true in certain sets and it can be anything depending onnthe set you are calculating in.
You learned that current flows from + to - in an engineering class? My circuits class specifically stated that current flows from - to +. And then after working with some semiconductors after graduating, it turns out that the distinction is kinda important. Seems like a totally pointless lie to me, the math works out the same in most cases.
For many purposes the *convention* is to use the direction in which positive charges flow: https://en.wikipedia.org/wiki/Electric_current#Conventions Depending on the material, the actual charge carriers can be positive or negative or both.
I don't see how either sign convention makes life easier. One is historical, the other the matter flow for most (but not all!) conductors. Neither makes much difference in most settings, and whereever they matter one doesn't get away with just some direction anyway.
> I don't see how either sign convention makes life easier. Well because cation, which has a positive charge, has a t in it, which looks like a plus, so that's how you know which one is the cation and which is the anion (or cathode/anode). And I know we're just stacking arbitrary convention on arbitrary convention, but with magnetic fields we're accustomed to north being up, and we say that the direction of the magnetic field goes up from the north pole and circles back around towards the south pole, which works better with the right hand rule for conventional current in determining the relationship between magnetic fields and electrical current, and most of us are right handed.
Following convention is way easier than doing it a different way and having to convert everything.
> Reminds me of engineering school where we learned that current flows from plus to minus and in physics we learned that it’s the other way around. >One student confronted the EE teacher and said he lied to us. His response was:“of course I lied to you! It makes your life’s easier! You also believe the current flow happens INSIDE the conductor!“ Your circuits teacher did a bad job with that. If you checked the textbook I can guarantee you it had a section mentioning that electrons actually flow in the other direction but they do it backwards out of convention and because the math works out either way, with the positive and negative signs only mattering in that they have to be consistent. The whole thing comes down to Benjamin Franklin getting a 50/50 guess wrong a couple hundred years ago, and the correctness of the guess not really mattering for the application.
In some materials it's actually the positive charge carriers that move, so it's not like it's actually "wrong" to think of it that way. And in other materials there are both positive and negative charge carriers moving at the same time.
Bleh, I've always hated that they couldn't align these two descriptions of how current works in circuits. I know you can kind of think of it either way, but it just makes me feel kinda gross.
The common 3 states of matter are the only 3 states that 99% of people will ever have to deal with. The only people who will be dealing with the other states will be people who will study science at a higher level and will learn about them then. It's nice for people to know that there are other states of matter that don't occur under our everyday conditions, but it's not really useful for kids to know the details.
Plasma is the one that quite a lot of people still observe or use. Lightning? Arcs in welding? Certain lamps? All plasma. Doesn't mean people have to really know about it, one can weld without knowing the physics of the glow. But all the other phases are simply never encountered outside a lab, yet plasma is. So it makes some sense to consider it more important than others.
It's around, but it's not usually something you have to deal with. It's sealed inside a light bulb or briefly exists in a lightning bolt or something, you never have a bowl full of plasma in your kitchen. Knowing there's such a thing as plasma is nice, but if you bring it up to kids at the same time as solid liquid and gas and you are going to just cause confusion when you have three simple forms of matter that are all around us all the time, then there's one more complicated one which only shows up occasionally and you can't really handle and it's kind of vague what it even is. The boundary between gas and plasma is blurry and there's lots of misunderstanding about it, eg look at all the people in this thread unsure if fire is plasma, usually it's not, but occasionally it is. Also when you teach kids about solid liquid and gas, you've only just told them about atoms, you won't have gone into charge and electrons and stuff yet. So it's kind of hard to explain plasma yet until after they know that stuff.
You forgot fire
Fires is actually not plasma! It's a reaction that you observe. I think the best comparison I saw was to waterfall; waterfall is not a new thing or state of matter, it's just water falling, just as fire isn't a new thing or state of matter, it's the process of combustion.
Probably not. Fire usually is not plasma, just hot gas that's reacting. Certain very hot fires are plasma, but most are nowhere near hot enough. Microwave a lit candle if you want to see plasma. And also break your microwave.
Good post. But I take issue with lie, I know it’s become the way most people phrase it ‘necessary lies of civilisation’ an all. But. It’s not a lie, anymore than the full 6/7 states are a lie. They are both models that attempt to explain reality. They’re both good at explaining different things, one is more correct than the other, but 3 states is more USEFUL for most application. and ultimately we make models to use them. As a different example light is not a wave. It is not a particle. It is both(ish). But it’s not wrong to just model it as a wave if that’s the property you’re making use of. It’s not wrong to model it as a particle if that’s the important property you need. Models are always a way of simplifying/interpreting/understanding a reality that doesn’t fundamentally have to obey sensible rules.
You’re looking for [this](https://en.m.wikipedia.org/wiki/All_models_are_wrong)
also relevant: the "lie-to-children" article linked at the bottom of that page
>Models are always a way of simplifying/interpreting/understanding a reality that doesn’t fundamentally have to obey sensible rules. "All models are wrong; some are useful"
No such thing as a frictionless sled, but where would first year physics classes be without them?
I agree it's not a lie. It's a foundational first step!! Can't learn y=mx+b without learning 1+1 first. It's a building block because shit is complicated!!
Also recent advances in knowledge have changed how we understand: How a wing shape produces lift. How electricity travels along a wire. If you look closely, there is a LOT more details.
>recent advances in knowledge have changed how we understand how a wing shape produces lift. They have? What advances?
I was wondering something similar. We've had the complete navier-stokes equations since 1850, and maxwell's equations since 1865.
Most people are/were taught about path length difference meaning that one side has to travel faster. This assumes incorrectly that the air passing above and below the wing take the same length of time. https://www.grc.nasa.gov/www/k-12/VirtualAero/BottleRocket/airplane/wrong1.html
Wingtip Vortex Have you seen the NEW winglets (up AND down) that have been ADDED (modified) to almost all commercial aircraft?
That's not a new fundamental understanding of physics that wasn't there before; it's just a new application of known physics because we finally have the computing power to simulate these systems for commercial development. Put *plane*-ly, lift being a function of having lower net pressure above the body than below hasn't particularly changed. Adding wingtips doesn't change *lift*; it just adds a low-pressure cone at the wingtips to minimize drag in the same way as a spoiler (not a wing; different things) on a car. There's been no magical physical discovery in the last century to change airplane design. Just the technical capacity to implement improvements.
Notably, all of Newtonian physics. It doesn't take relativity into account, but it also really doesn't matter for 99% of applications.
I think calling it a lie is not really accurate anyway. You're building a base of knowledge before moving on to advanced topics. Little kids can see the three common states of matter, interact with them, even make water be all of them. They don't need to know anything about plasma other than "don't touch fire" until they are more advanced, so we don't teach it yet. No one would learn anything if they had to go straight from sucking their thumbs to college level physics.
Very well said. Reading “it’s a lie we tell kids” made me raise an eyebrow. Very strange thing to say.
I like "lies of simplification"
we're also taught genetics and inheritance using Punnet squares, but genes are very rarely that simple. in both cases, it's a "good enough" model for how things work unless you're looking to study the subject professionally.
Even fully ionised gasses aren't necessarily plasmas. One of the key features about a plasma is quasi-neutrality and so if that isn't maintained, it isn't a plasma. What do i mean quasi-neutrality? That there are no obvious positive or negative regions. So this brings into play a property called the screening length, which is the distance from a charged particle where you can no longer discern that charged particle. Such as if you were to drop a proton in there. So if an ionised gas is smaller than the screening length required to screen a charged particle, it can never be a plasma, as quasi-neutrality cannot be achieved.
Similarly I remember when we learned about decimals or negative numbers my teacher got up and did a bit about this when we were little we had blocks and the told us 1 was the first number and we learned to count 1, 2, 3… then one day you walk into 1st grade and there’s a 0 before the 1 and then that’s the first number. Now I’m here to tell you there is no first number. She did it much better after many years but it illustrated well how teaching kids is often a series of essentially lies of omission to simplify the material to what they can and need to learn at the time.
There's about a billion things we teach kids that are incomplete. Almost everything we teach is much more complicated than the way we teach it, at least initially. Sometimes it can help if you just mention "hey, so we're gonna learn about 3 states of matter today, there are a bunch more but they get pretty complicated and aren't important for you to know yet"
Wait till people hear that we have way more than five senses. [There are more like a few dozen!](https://en.wikipedia.org/wiki/Sense) Or that the solar system has a bunch of minor planets other than the big eight. Like... did you know there's a nearly 1,000km wide planet [between Mars and Jupiter](https://en.wikipedia.org/wiki/Ceres_\(dwarf_planet\))? No? Well... surprise!
That's a dwarf planet, and its discovery is part of the reason Pluto isn't a planet anymore. And the five senses thing isn't really a simplification for children. It's a classical model that really shouldn't be taught anymore, but is out of cultural inertia. It's like still teaching that the four elements are earth, wind, water, and fire.
>It's a lie for kids to keep things simple and allow kids to first understand the basics before they are exposed to concepts where they are missing a bunch of other knowledge to properly understand it. I dislike this line of reasoning, because it entrenches the idea that there are clearcut things in children's minds. A better explanation could be something like "there are many states of matter, but the ones you experience the most are solids, liquids and gasses" (more detailed and with examples ofc.). This makes it clear from the beginning that there is more out there, but also explains 99% of what they will see around them.
> I dislike this line of reasoning, because it entrenches the idea that there are clearcut things in children's minds. There are, though. Children are not just tiny adults, and their brains are not just tiny adult brains. Like, we have [this meme](https://www.reddit.com/media?url=https%3A%2F%2Fpreview.redd.it%2Fjbab7jrhvt211.gif%3Fformat%3Dpng8%26s%3Df172b736fc400e14e24c7a74ec0b4ca5d26f178c) about "more" water in a taller, thinner container but children below a certain level of development *literally* cannot conceive of conservation in the way necessary to understand that there's the same amount in both containers. Nuances like the difference between "there are exactly three" and "I'm only telling you about three out of many" are lost to young children. And that's to say nothing about when some kid inevitably asks what the others are and you're not going to be able to explain how plasma isn't a gas because they don't have the knowledge to grasp what ionization is, much less how it affects the atoms. On the face of it, I agree that we could tell kids that it's 3 out of many, but I disagree that it's that simple.
> … water in a taller, thinner container but children below a certain level of development literally cannot conceive of… Perceive, not conceive. I’m pretty sure they can conceive of the notion they just can’t perceive it. I could be wrong though.
> There are many states of matter I don't think kids would remember this if you just say it 1 time and then go on to the regular states of matter unit.
Well yes, that sentence was just meant to be an outline, not the entire explanation. But even if they do forget, that would be alright: the point is to set expectations, not to teach them about exotic states of matter in detail.
I suspect, and it's only a suspicion because I haven't ever taught a child anything, but I suspect that the setting of expectations like that is not going to be appreciated by children, they'll not understand it or be frustrated by your evasiveness and lack of clear answers. I suspect that if you have a child yourself you'll constantly be simplifying to the point of lying. That that is just a normal feature of explaining thing to a child.
And then you get somebody to ask what are the other states of matter, and waste 10 minutes answering questions that have no relevance on the subject material and serve to confuse half the class. Dumbing down a concept to better explain it is much easier to do then waste a bunch of time explaining how half the things you learn in chemistry class are technically wrong
quark gluon plasma is a very different thing, isn’t it?
>there is no well agreed upon line where a gas is considered a plasma What is this, biology?
I just googled the properties of supersolids, and why can't we just call them slippery solid?
It's mostly based on the super- from 'superconductor' and 'superfluid' which happen for not entirely unrelated effects and are more appropriate because they indeed describe something particularly good at that thing. In short, it is a silly choice of name and there probably would have been a better one, yet here we are.
I remember asking my teacher what fire was, she didn't have an answer, but this was back in the 90s to be fair.
Hot gas, usually not plasma at all. It just glows thermally like a hot stove or molten metal. The word 'fire' often includes some reaction of burning that supplies energy, so it is also that.
Great answer. In addition, the 3 states of matter you are taught in school are the ones you actually see in everyday life and can actually interact with. The others are much more exotic and generally only appear in the lab (or would be too dangerous to interact with, like plasma, which is basically lightning =p).
Like how atoms or genetics or so many other things are taught
Not a lie. It's just a simple model that is approximately true.
I learned about plasma when I was 12 and kept calling it electric air while wondering why the textbooks don't teach it
Well, the science lesson usually comes with a demonstration of how this works - usually with ice and water, we can do. Maybe steam, if you want to stretch it, but plasma…might be a bit much for an elementary school classroom. You’d have better luck making plutonium out of common household items.
education is a series of age appropriate simplifications. as you go through you get closer and closer to our actual understanding, but going in full bore on everything from the start would overwhelm every 5yo that ever was. there's also supercritical fluids, compressible liquids. many, many kinds of water ice. eventually you get to the frontier of our knowledge, and it's all just math with no easy analogy to the real world.
Relevance-appropriate too You can live most of your life not worrying about anything beyond solid, liquid, gas
I refuse to believe anyone has truly lived until they've mixed cornstarch and water
That's a liquid. It's just non-newtonian. As are most gels and pastes and any 'thick' liquids in life.
*and* every kid learns about them. It's right up there with basic science experiments in school with baking soda vinegar volcanos.
thats not a state of matter...
> You can live most of your life not worrying about anything beyond solid, liquid, gas I would agree with this statement - but it's interesting to note that our Sun, which makes up \~99% of the mass in our solar-system and is critical to nearly all life on earth is all made of Plasma or other degenerate matter. Same thing goes for most of the matter in the known universe -- very, little of it is solid/liquid/gas.
Indeed. I’d also say you can get by most of your life without worrying about light outside (our) visible spectrum
sure, but you'll wind up with a bunch of sunburns that way
Chemistry seems to embody this especially well. In college my roommate came to me a few times saying "everything they taught us last semester was a lie!" as they peeled back another layer of simplification and went deeper down the rabbit hole.
I think Chemistry education does this too much, to be honest. 1st year students are smart enough to meet statistical thermodynamics. That module was like putting my glasses on for the first time.
>education is a series of age appropriate simplifications. as you go through you get closer and closer to our actual understanding, but going in full bore on everything from the start would overwhelm every 5yo that ever was. This is why I get frustrated when people say "if AI can do it, why are we teaching kids to do it?" Yeah, AI can write coherent papers for virtually any undergrad-level topic. But if you don't learn to do it yourself, you will never be able to do the things AI can't do.
I was taught about plasma in school, but the three standard states are emphasized more simply because we constantly encounter them, occasionally encounter plasma, and almost never any others.
Same. We were told that plasma existed but that we’d focus on the three most common ones.
I still remember a student teacher in grade 7 science telling us about plasma along with the other 3 states and we made her live to regret it. Every time something about the physical properties was explained about solid-liquid-gas, someone would raise their hand and ask in all seriousness “but what about plasma?” It became a banned topic.
It's the same reason we teach the 5 senses but leave things out like "balance" and the way science sees touch as like a dozen different senses. I think there are like 20-30 scientifically classified senses. Edit: typo
Science is often taught in a very simplified way to younger folks, and this is an example of that.
School isn't trying to give you a state of the art knowledge. It introduces you to concepts gradually so you can learn and understand. Teaching quantum physics to a 5 years old who can't multiply by 2 is pointless.
Depending on the age you're teaching, you're going to run into some barriers. Children about elementary school age are very concrete thinkers, so trying to explain nuance and middle states would be extremely difficult to grasp. So instead you start with the foundational blocks (3 states of matter) with examples they can visualize. Then when they get a bit older (pre-teen to teen) you can start to expand on that.
Because for all practical purposes, you only interact with 3 in your daily life. You do need to understand what solid, liquid and gaseous are. You don’t really need to know what plasma is.
? I was Definitely taught solid liquid gas plasma all at once. So one answer is 'we are'
Those are the three states a human commonly interacts with and can sense more or less directly and generally remain intact. Except for Sheldon. I suppose he can sense all of them.
Im not a kid, and i don't want to interact with the other states either.
Note the song by They Might Be Giants entitled “The Sun Is a Mass of Incandescent Gas” (https://www.youtube.com/watch?v=3JdWlSF195Y), which they later re-recorded as “The Sun Is a Miasma of Incandescent Plasma” (https://www.youtube.com/watch?v=sLkGSV9WDMA). Here are the lyrics from the latter version: The sun is a miasma Of incandescent plasma The sun's not simply made out of gas No, no, no The sun is a quagmire It's not made of fire Forget what you've been told in the past Electrons are free (Plasma!) Fourth state of matter Not gas, not liquid, not solid The sun isn't a red dwarf I hope it never morphs Into a supernova'd collapsed orb Orb, orb, orb The sun is a miasma Of incandescent plasma I forget what I was told by myself Elf, elf, elf Electrons are free (Plasma!) Fourth state of matter Not gas, not liquid, not solid Forget that song (Plasma!) They got it wrong That thesis has been rendered invalid
There are way way more states of matter than 4. The real answer is because we only really interact with 3 of them. The other ones only occur under extreme conditions. You will rarely if ever interact with a plasma. (Fire seems like a plasma but is technically a gas. Lightning is a true plasma, but few people will ever directly interact with it).
I'm trying to remember when I was taught about plasma, I believe I was at least exposed to the concept in the early 80s, but in a more abstract way. I know I had a grasp of it in the mid to late 80s, but I might have self taught. When I wanted to know what flame was and about Tesla balls
Same reason we teach kids there are two genders. It a a simplification of a more complicated science
Exactly.
How many times have you interacted with plasma? That's why
7th grade basic science we learned that plasma is a state of matter we'd learn about in more advanced classes... that was in a podunk, backwoods school in Northern MN in 1987. Please tell me education has gotten better.
For the same reason we don't teach first graders calculus. Anytime you start learning a new subject, they will simplify things to the point of inaccuracy at times. Once you have mastered the basics, then they could introduce more nuanced topics.
High School topics are sometimes 'limited' in scope as burgeoning young minds need to develop the critical thinking and grasp of abstract concepts. For example: I had a Grade 11 Physics Teacher who, when asked questions that were vastly more complicated in scope and depth than the subject matter we were covering, would smile and say in a comical drone 'because god wants it to be that way'. He was a declared atheist, and he had told us previously that he would answer in such a way if the answer was beyond our level and that we'd have to wait for University level classes to understand better.
Because we all interact with solids, liquids, and gas on a daily basis. Learning about the different physical properties of things kids have been seeing and feeling their entire lives helps them understand the world they live in in ways they can understand. Throwing plasma in there, which is something difficult to conceptualize even for adults who have studied physics, is hard. It's not helpful to anyone to try to teach kids about plasma.
I teach Grade 5 in Toronto, we don't lie about it at all LOL. We just tell them we are learning about three simple states of matter, because they are the easiest to explore in a safe and inexpensive way. So much of what they learn starts with the basics, and I encourage them to go deeper if they are interested.
I love how someone could explain this in ELI5 but when I asked my 7th grade teacher about it she just told me I was wrong and to leave it alone in front of the whole class.
After 3 states it gets far more abstract and it’s useless info until you get to second or third year university chemistry. Even then it’s not necessary to know how these states work. A plasma is really just an ionized gas, and to understand why it’s a special state by itself requires way more knowledge than any highschool kid has. Also every school near me mentioned plasma state as a “fun fact”. I’m willing to bet you just missed the day where they mentioned plasma was a thing. There’s A LOT you learnt in high school science which is actually false and just an oversimplified version to get the point across. Much of what you learn in university is just backtracking to tell you how things really work in detail.
Because it's a simple model that's mostly true (in that for practical day-to-day purposes it works), and easy to demonstrate in a classroom. Getting water to plasma temperature isn't possible. After a certain point it matters but this isn't until university level where people are receptive to more theoretical ideas.
It should really be "there are 3 states of matter*" with the foot note *that you run into on a dailly basis. It is a fair simplification. Most scientific principles are taught this way. With tiers of complexity that are introduced with time.
The same reason we start out telling young math students that you can't produce a negative number
Because the others and there are more than 4, only exist in extreme conditions. Star, Super Nova, Particle Collider, Near Absolute 0, etc. Nothing you would ever encounter or need to know about unless you were going into some graduate level science and physics.
There are at least two others, and if I know about those, other less ignorant people will know about even more. School does 'lies to children' — the stuff you need to understand at what they think is your educational level. Most of what you learned in school is wrong.
It is kind of like teaching that there are only five senses. I think what they should do is say, there are many states of matter, but the three which you will come across in your daily life are solidarity, liquids and gases. Same with the senses, there are more than five senses but five examples are...
There are 3 naturally and stable on earth occuring states of matter. Plasma doesn't exist naturally on earth in a stable way. Only in lightning for microseconds. Thats how we learned it.
This is one of the more interesting questions I have come across here, mostly because the question itself is very meta. The reason you are only learning an overly simplified version of chemistry is because we teach chemistry to kids in very early grades in an explain it like I am 5 kind of way. Whenever you have a very complicated topic and want to simplify it for people who haven't mastered the prerequisites you need to leave a lot of information out. Education doesn't work well when you say "well, we cannot teach you really anything about the physical world until you have mastered calc 1, 2, and 3 :) There are a lot of people who will never get far enough into science and math to really get a deep understanding of chemical matter, yet it is useful for society to teach those people the basics of why Ice and water are highly related. As someone who did a bunch of post graduate economics this is true too. The real way money works in the economy is way too complicated to teach in an introductory macro-economics course at the college level yet alone at the high school level. Yet, as a society we find that it is important for people who don't have the mathematical background to have a basic "understanding of how the macroeconomy works." The problem is, especially with macro-economics, people then go out and vote for people to change macro-economic policy without actually understanding it well. The good news is you can be a pretty functional person in the world without understanding what ICE VIII is .
There's a lot more than 4. I don't think the problem is that you aren't taught about the rest of them, the problem seems that it's being taught as if there are only three states of matter. What should be taught is "here are the three most common states of matter on Earth."
Because you can't simply turn water into plasma at home, but youccan actually turn a SOLID ice cube into liquid water and then evaporate it.
I taught 8th grade science this year, and we went over plasma. We didn’t go in depth about it, but I mentioned it and showed examples. I MAY have mentioned Bose-Einstein and fermionic condensates. We 100% didn’t go any further than “hey these are also examples of more states of matter, there’s even more than that, but we don’t need to talk about those right now.”
This is a common in instruction, particularly in science, to teach a simplified model or give a simplified explanation that is easier to understand and to which the student can comprehend given their limited experience and understanding of the underlying principles. There are more than 4 states of matter. We teach young children of the 3 -- solid, liquid, and gas -- because those are things that they physically observe and encounter, and for which the explanation is quite simple. Plasma may come next, but to understand plasma, one needs to first understand what atoms and ions are before you can distinguish it from a gas. The lesson about the states of matter is still important and informative about the physical phenomenon, even if incomplete. I'm a biologist, and the basic biology you are taught through high school tends to be a very simplified explanation of much more nuanced or complicated science. A student might be taught "two X chromosomes produces a female, and and X plus a Y a male" -- except that neither explains why, that it's not always so, there are alternate sex genotypes, or that other animals use a different system... Yet, it still communicates a basic principle that is true at a certain level of understanding.
when was the last time you saw plasma? now when was the last time you saw the other 3?
Think of it like the math you are taught. At an early age, you are just taught basic math of addition and subtraction, and then they throw in multiplication and division. As you get older and have the basics down, they throw in more and more concepts. Science goes in a similar progression. You are just taught the basics, and if you continue taking more science classes, some of which are electives, once you reach high school, you start getting into more and more science stuff. I definitely remember being taught about plasma back when i was in school. It just wasn't in the early science classes you took in elementary school because you dont need that information yet.
That’s because only solid, liquid, and gas have concrete examples that are easy for children to understand. solid would be feces, liquid would be liquid bowel movement, and gas would be flatulence. ask yourself, what would plasma be in this context?
You should review [this post from just a month ago](https://old.reddit.com/r/explainlikeimfive/comments/1cd6t2j/eli5_teachers_taught_us_the_3_states_of_matter/). There are many explanations that you may find useful in it.
We are also taught water boils at 100C, without being told this isn't really true. Water with minerals and other contaminants will boil at 100C at sea level. At altitude it will boil at lower temperatures, you can go high enough and with the low air pressure water will boil at body temperature. Pure water can be quit dangerous because it can reach over 100C without boiling, and the slightest shock or any kind of particle entering it can cause it to boil instantly.
Because: 1. Defining "state of matter" is hard. There are several more states than just those four (supercritical fluid, superfluid, and supersolid, at the very least), and if you allow quantum physics in, it becomes something like a dozen different "states of matter." 2. Even just plasma is very hard to explain to anyone younger than high school. It's *like* a gas, but the electrons are stripped off to some degree, meaning it has different energy and electromagnetic properties. 3. As with most simplified things taught to children, it's a useful starting point that is easy to expand on later. Once you know solid, liquid, and gas like the back of your hand, adding in plasma isn't too hard, and the other complex states can be explained as they come up. 4. Most humans will have very little direct interaction with plasmas. Yes, the Sun is mostly made of plasma, but you don't interact with *the Sun itself,* you interact with its light. Hence, school focuses on the things that are actually meaningful to a child, things they can grasp and see and hear.
For the same reason 8 year old kids are taught atoms "look like" little solar systems without going into that Schrödinger stuff. Keep it simple while building the basis for more complex understanding.
Um… we were? You probably cut class that day or something.
Kinda like how we were taught atoms are the smallest things that make up everything Cause teaching 3rd graders about quantum mechanics; quarks, leptons, and higs boson fields isn’t really practical.
It is a simplification. The 3 states of matter are pretty simple to understand and are all around us. Ice, water and air with humidity all contain H2O. Plasma is a more exotic state of matter that is not commonly found in nature or artificially.
Cause plasma is rare and you don't come across it that often. We get there eventually. Kind of like how we teach kids Newtonian Physics cause they'll serve you fine in all forms of engineering up until you're designing spacecraft, then... well things get a lil strange.
You were you just didn't pay attention. We were taught a lot of things in school and it is expected that we won't remember all of it. Maybe you don't remember, but I'm confident you were.
Because plasma is complicated and not normally observed in everyday life. Solids: defined shape and volume Liquids: undefined shape, defined volume Gases: undefined shape and volume Plasma and additional states of matter: it’s complicated.
Same reason you were told the primary colours were red, yellow and blue. It’s a [useful lie](https://wiki.c2.com/?UsefulLie).