How many thoughts are contained in a Mars Bar? - Sixty Symbols
Vložit
- čas přidán 7. 06. 2024
- Discussing entropy, energy, information - and Maxwell''s Demon.
Featuring Professor Phil Moriarty. His blog for more discussion of this: muircheart.wordpress.com/2016...
Visit our website at www.sixtysymbols.com/
We're on Facebook at / sixtysymbols
And Twitter at / sixtysymbols
This project features scientists from The University of Nottingham
bit.ly/NottsPhysics
Patreon: / sixtysymbols
Sixty Symbols videos by Brady Haran
www.bradyharanblog.com
Email list: eepurl.com/YdjL9 - Věda a technologie
This video was some real...
food for thought.
heh, I see what you did there
This needs to be the top comment. We need to make this the top comment.
Idon't know how. Maybe if I had a Mars bar I could.
sweet comment.
He keeps trying to describe entropy, but the descriptions just keep getting more random.
i see what you did there XD
Entropy is a difficult thing to explain. Alle easy pictures tend to lead to false assumtions. It's a real subtle topic.
the more i learn about entropy the more i'm convinced that simple explanation 'entropy is disorder' is very very wrong and harmful to actual understanding.
And now you can't unsee it, Ahmed!
Next someone will discribe recursion?
"If we work in PROPER units, which is Joules, and not the calorie nonsense."
*hear eV crying in the distance*
Also, 1 food "calorie" is equal to 1 kilocalorie, so each "calorie" you see on the packaging is actually 1000 calories. Not sure why they specify it that way.
yeah, that one really cracked me up.
You can tell he's passionate about what he does.
Or just insane and smart.
+Calvin K thats the same
ikr, i love this guy.
Can't wait to start lectures with this champion in September :)
Not at the level of the Kleine bottle guy though.
So if I understand it right, I just got to eat Mars bar and I get my PhD in Physics?
I have one question, Mr.Moriarty,Entroy is a measure of how a system is Most likely to progress in time, since the probability of a group of states is larger than a specific kind of state?
Information in Mars is random and you have to do work to arrange it into knowledge of physics, and given the number of molecules, it will take some time.
Entropy measures a system's current state, the *difference* in entropy between two states is a measure of how likely the system is to progress and is correlated with how fast it will progress there.
Since it won't work because information in Mars bar is random, would it work if I ate a brain of someone with a PhD ?
ILYES
Yes, but you have a 50% chance of zombism.
Hi Phil. I apologize for my previous comment, I ended up being as insensitive as the worst trolls in my own videos. I love this channel and I am really thankful for the dedication and generosity of everybody involved, including the camera guy, the producer , editor, etc. You guys deserve better than a quick and dirty comment typed during lunch on a smartphone.
I am reading James Gleick's excellent "Information: a theory, a history a flood" (after reading "Chaos") and I just read about the Maxwell's daemon and entropy and information and energy and all of that, and I was glad to watch your video in such a convenient time, and please allow me to add a few remarks about this specific video.
This whole channel is very authentic and spontaneous precisely because it' so improvised and natural. I also publish tons of videos myself, and I always improvise and publish the result as-is, no editing or embellishments. Improvisation, though, comes at a risk: we may lose focus and precision, and when it happens it is very difficult not to show it. If we lose track of our thoughts our viewers will get lost too, and that's what I think it happened this time.
if we take into account the expectation created by the title and the way you managed the available time, you spent so much time trying to communicate the notion of entropy that there was little time left for the concept of energy x information, which was conveyed in turbo speed.
so... sorry for being unfair and superficial and mean in my first comment (which I deleted to avoid unnecessary flames), and my kudos for your inspiring work. I am not a native speaker, I am not a physicist, but you guys have been providing wonderful food for my hungry soul.
best regards from Sao Paulo, Brazil.
Wow, respect! Realising your original comment was lacking nuance and coming back on it takes a lot of courage.
"Phil does entropy... again." If you've not seen the earlier entropy videos with Professor Moriarty (or, indeed, any of the other videos he's done), do watch them! They are quite entertaining and also educational.
Phil Moriarty is an idiot
I know words, I have the best words. Nobody respects women more than me. I am the least racist person who you have ever met. Nobody lies better than me. Believe me. Sad!
Had to double check the title of this video.
Now, tell us how many licks it takes to get to the center of a tootsie pop.
+Gareth Dean joking aside, do you know the answer to that?
+Sixty Symbols Should be a topic for Periodic Videos, I suppose. "Assuming every lick removes a layer one molecule thick off the tootsie bar,..."
My six year old daughter actually kept track and it was 96 licks.
+Sixty Symbols Around 1000+ licks to a center. One less worrying thought, one attogram (pun intended), less on your mind ;)
Sixty Symbols
I know *an* answer, having a friend who did this as a science fair project. They got an average of 92 licks with a standard deviation of 12 licks.
Of course the sample size was only 30.. Parents just won't buy candy for kids, even for science.
I understood about nothing in this video, but man, can Phil talk and generate enthusiasm!
Prof Moriarty really should have his own channel....He is fantastic. The passion he has is contagious.
He has his own channel actually.
He does, search for: Philip Moriarty
Mind Blown! Thanks
Google, and you shall find...
Phil Moriarty is an idiot
Took me almost my entire undergraduate coursework before I found a teacher that taught us in discrete terms what entropy was. Scary that most professors in the sciences have no clue what entropy means; usually just a vague understanding of a single expression or character of entropy.
Guy was an aeronautical adviser to the white house. I was fortunate to be placed in his class.
Would be nice if you broke that huge number down further at the end. It ends up being roughly 8 billion years of 1080p 60fps video if there's no fancy interframe video compression. Also it would be enough information to store the entire Internet roughly 30 million times over.
+DrMrProfJacob cool
If only thinking was a better way to lose weight.
+liltonyabc Unfortunately I think it wouldn't make much of a difference in today's society! lol
Always delighted to see Phil talking. Hes so passionate and moreover his Videos always get very long, what I really like.
I love professor Moriarty!!!
My new favourite quote, "go on, let me write one equation. just one."
So happy to see Professor Moriarty again! Ahhh this is my favorite channel on CZcams and I was wondering if I'd ever get another physics video from you all. People love your content!!!! Please keep the physics coming!
did he just assume the gender of the demon?
this is one of the most fascinating videos i've seen on youtube in a long time, even on this channel.
+aksen303 thanks for taking the time to watch it
I LOVE IT WHEN HE SHOWS US THE MATH EQUATIONS AND STUFF.
MUCH LOVE SIXTY SYMBOLS
really love this channel
+Cullen Gilfillan thank you for watching - we probably wouldn't get to keep making videos if no-one ever watched. :)
+Cullen Gilfillan thank you for watching - we probably wouldn't get to keep making videos if no-one ever watched. :)
Speaking of replying, you guys did it twice xD
I love how most physicists are always so passionate about what they do. It's really special seeing a grown man be this excited about something; passion is something people tend to lose a lot as they grow older.
One of my favorite videos of all time
Love the energy of Professor Moriarty! :) I could listen for hours.
more of prof. Moriarty please :) I can watch and listen to him for hours...
Fantastic video! It would be so awesome to see an actual lecture by prof Moriarty! Sort of like what Stanford university does with their profs. Still i`m so damn happy to be able to get this awesome information well presented and free. What an awesome world we live in!
Very nice video. Nothing new for people who studied science, but probably interesting for general public.
But I cant help myself... That passion of professor Moriaty is so contagious. Must be so great to be his students. I´d wish to have such "burning" teacher when I was in university.
And thank you, Brady, for longer video! :-)
A Sixty Symbols video a day helps you work, rest and play
Phil is the best part of Sixty Symbols
Idk what is it with this information-entropy topic that i find it enormously fascinating
8:56
He really caresses that demon alot. Not sure if sweet or creepy.
Though I enjoyed the other entropy videos more, I would still like to continue exploring this subject if it's not a "dead horse" yet!
These are my favorite videos as the concept itself is so mesmerizing. Please do more if you don't have any other ideas!
You get a much larger number of thoughts using E=mc^2 for the mass of a mars bar
Love watchin' good teachers teach..
Prof. Moriarty is one my favorite guys, ever.
Good to see Prof Moriarty is back :)
Btw. "Gedanken" means nothing more than "thoughts" in german.
So Gedankenexperiments is a thought-experiment, just in case someone was confused.
Very interesting topic thanks for sharing
So if someone offers me a penny for my thoughts, am I still being overpaid?
+Ouija ha ha
There is an article in Nature magazine 406(from 2000) by Seth Lloyd titled "Ultimate physical limits to computation", which talks about this and is exceptionally interesting, even if you ignore the math. He's also published a great deal of other papers dealing with information, entropy and basically everything Prof. Moriarty talks about here.
I like it when my brain hurts after watching these, means I'm learning. Thank you for these videos.
You know, the flaw in this thought experiment is the use of a Mars bar instead of Snickers.
"Go on... let me right one equation on the board, just one" xD
great video
looove your show.. seen em all!
Great episode! An energy of a thought!) I think, we are close to measuring this directly, having the MRI scanners, etc, etc...
However, you won't get all these thoughts from one Mars Bar. Take into account what percentage of the energy actually goes to the brain. Besides, most thought processes are unconscious, like registering the information you receive from your body...
This is why I hate mars bar
still better than snickers
i hate you too
MarsBar ayyy lmao
I hate everything.
Interesting, I never took the time to dissect it in that way. I usually just think of it as 20% of my caloric intake going to my brain. I guess it's simply the difference between macro and micro economics. I was glad to see Maxwell's Demon and entropy in relation to the process though. They probably could have gone further with that, but they were trying to keep it brief.
Brilliant! Information and work are related precisely via a formula that describes how much work you can get out of one bit of information. Inversely does this also describe how much work you need to extract one bit of information?
How does this relate to the cost of computation? IIRC Landauer showed that in principle computation can be made free by making all gates reversible and putting the computer in a heat bath.
This is such a fascinating topic, please show us more!
I was starting to miss Prof. Moriarty, he used to appear in many videos a couple of years ago.
In the case of the piston, is that really a free lunch or is it not "just" converting the heat of the particle into piston movement?
Does the amount of energy also depend on the mass of that particle, or just its temperature?
I'm not gonna kid but I thought IHE gave in
me 2 :D
I imagine we simplify images a lot. I don't remember each individual pixel. It becomes more like a vector image. And we take shortcuts as well like if there is something repeating we just remember how many times it repeats, we forget details etc so there is some compression too.
Ok, so, What if a sheet of Graphene or something had "panels" on it which hung down in a fashion that is could not switch to the other side of the sheet due to steric hindrance or whatever yet atoms coming from one side of the sheet were able to alter the shape of the "panel" in such a way to be capable of coming through when it had enough energy however it could not return back the other way? Would that not only be relatively easily possible but be analogous to Maxwell's demon?
We see similar stuff happening on Cell surfaces all the time where molecules of specific types or energies are allowed to pass because the specific molecule changes the configuration of the pore and allows it into a cell. Granted this is slightly different than the hypothetical Graphene I mentioned above but it shows one way transmission of molecules.
How did they derive that conversion ratio and does it have any practical utility?
Now I'm really thinking of applying to Nottingham for physics because of Prof. Moriarty.
This video was great
I am still not sure about a thought, you define it as the picture but is there any consensus on what 1 unit of information is? or does it depend?
If I take a section of space and randomly divide it, over a long enough time I'm going to get lucky and find a section that isn't perfectly uniform and will have a natural gradient. It may not be a perfect gradient, but it should be sufficient to do some work (and should resemble a perfect gradient moving towards entropy).
How do you account for this within the understanding of entropy? Given infinite time, even a random arrangement should move towards something that doesn't resemble perfect randomness.
Unless there is no energy within a system, there is a possibility that some of the energy will dissipate in a configuration that appears to be lower in entropy than it's surroundings.
Very fascinating! However, as a neuroscientist, the metaphorical use of a "thought" confounds me immensely. Let's assume the thought is truthfully represented in your brain with the resolution of a 1080p still picture (it's not, but let's), you would still need continuous energy input to keep the representation active. *So how does time factor into this?* Is the associated energy just for one "frame", if you will, of thought processing (and there is no such thing)?
That was a great video
There's something strangely satisfying about watching Prof Moriarty illustrate his points with a goth doll. :)
This video is a giant add for Mars Bars!
It's an interesting idea to put "1 thought" as one frame of 1080p video because then you can work out how long of a HD video you get out of a given amount of energy. As it works out, one mars bar contains just about enough energy to film the time from the big bang to now in HD.
“We all behave like Maxwell’s demon. Organisms organize. In everyday
experience lies the reason sober physicists across two centuries kept
this cartoon fantasy alive. We sort the mail, build sand castles, solve
jigsaw puzzles, separate wheat from chaff, rearrange chess pieces,
collect stamps, alphabetize books, create symmetry, compose sonnets and
sonatas, and put our rooms in order, and all this we do requires no
great energy, as long as we can apply intelligence. We propagate
structure (not just we humans but we who are alive). We disturb the
tendency toward equilibrium. It would be absurd to attempt a
thermodynamic accounting for such processes, but it is not absurd to say
we are reducing entropy, piece by piece. Bit by bit. The original
demon, discerning one molecules at a time, distinguishing fast from
slow, and operating his little gateway, is sometimes described as
“superintelligent,” but compared to a real organism it is an idiot
savant. Not only do living things lessen the disorder in their
environments; they are in themselves, their skeletons and their flesh,
vesicles and membranes, shells and carapaces, leaves and blossoms,
circulatory systems and metabolic pathways - miracles of pattern and
structure. It sometimes seems as if curbing entropy is our quixotic
purpose in the universe.”
―
James Gleick,
The Information: A History, a Theory, a Flood
That demon doll is just beautiful!
How many mars bars will it take moriarty to realise that winters is a joke?
More videos from Prof Moriarty please!
@7:55 I was interested in the "Spherical X" route that Leo Szilard went down. Wonder what that is?
+Philip Moriarty oh... spherical COW - thanks!
I've only taken a mechanics course in physics but I was taught that work is equal to the force times the displacement of a particle. I don't understand when he says there is no work done when moving the piston or the barrier. I understand there is no friction but would there still be a force moving the piston back and forth?
Thanks.
This is not related to this video but could you do some videos on nuclear fusion and fusion reactors that we are trying to build?
I know this was just a rough explanation, but are we talking this amount of energy for thinking one thought? For how long, If I keep thinking about mars bar for the whole month, at least 5 hours per day just thinking about mars bars (and maybe diabetes) and then at the end of the month I eat it - would the energy spent thinking about mars be more than actually eating it? What I'm trying to tell is that I'm to lazy to go for a run, but if I keep spending my energy on thinking about running, would it eventually be as good as one run?
edit: typos
I am wondering about one thing: I can live with a case where I don’t do any work when moving the piston. Weightless piston, no friction and moving perpendicular to gravitation, so on the paper I don’t apply a force. But how does the molecule do work then?
There was a brilliant documentary on this topic by Jim Alkilili. Forgot its name but it's something to do with information in the title of the documentary. Fascinated me ever since and uses animation to describe it rather than just a cardboard box and weird kids toy haha.
5:09 Brady's best line ever
14:04 We assume that the image is 24 bits/pixel but then what appears on the screen is more like 256 colours or so. Is it supposed to represent the 'compression' or is it just an artistic thing?
The thing about Maxwell's Demon, if the barrier is frictionless it still requires energy to accelerate.
Think about the electron going through a point on the plane of the barrier. Changing whether that point is passable or not requires energy.
To block a particle, the barrier has to have mass or charge. In order to accelerate the mass or turn the charge on and off, you'd need energy.
I suspect, considering each action only moves one particle across, that would outweight any gain.
Woah woah woah. Slow down. Nobody can accurately think of a full picture 1920x1080 24 bits. A thought (even in picture) is more likely a few concepts like: Phil in a theater raisin his hand with a demonic doll on the desk. Which sounds more like a few hundreads bits.
its an aproximation since we dont realy know how the brain thinks
gytux0258
I know. And even tho, that would only make the number of thought in a Mars bar even higher.
I know how the brain thinks...
_(short pause)_
Just like that.
Brains are more apt to process information by discarding about 99% of it. In that sense, it's not really appropriate to just calculate the bits of an image. You only process the "important parts", the so-called "exformation", anyway. The information stream may be large, but it's cut to size like a filter. This is how we don't collapse from the information input of just living for a single second in reality.
*****
I'm responding to a post. What am I not supposed to take literally?
I know that 60 symbols is ballparking, but they're ballparking in the completely wrong ballpark.
I'm a little confused on the whole getting free work out of moving the piston on its own. Dr. Moriarty says that moving the piston when it doesn't have to move the particle is workless because it's frictionless, but isn't just the act of moving it adding work into the system? The only way moving the piston could be workless is if the piston was massless, however, if that is the case, then the particle moving the piston with its entropy would be workless too because of the piston having no mass.
Are we saying then that information is another form of energy? Can one state that for a system in a "well known" state to spontaneously degrade into a less "well known" state, that the system must have done work? Like accelerated some mass, for instance?
Also, I'm confused about what is meant by "known". What is doing the knowing?
how do i learn more about this?
Hi Brady! Love your videos to bits. Can we have a new relativity video with Professor Mike Merrifield.
I don't understand. How is knowing on which side the ball is 1 bit? Isn't it 2 bits (because right side yes/no, left side yes/no, are 2 pieces of information)? Also, in order to know the place of the ball, even in 1 dimension, shouldn't it know information about every cm (or smaller) on X to determine where exactly it is?
Do a video about the EM drive!
Phil I have a question regarding the piston thought experiment. when the molecule hits the piston, it imparts energy into it, so the moleculre loses kinetic energy. Isnt the piston's work energy just coming from the thermal energy of the molecule and hence not violating 2nd law? I'll grant that you DID say it was a massive oversimplification!
If the demon is making free energy....then we can solve a lot of problems...then why is it still a demon?
Bc it wants your soul in exchange
+StrikePlaysGames Then never mind, I'll just burn more coal, it's better that way.
Because it's a daimōn:
en.wikipedia.org/wiki/Daemon_(classical_mythology)
en.wikipedia.org/wiki/Demon_(thought_experiment)
It's not making free energy, that's the thing. The energy that the demon needs for the information needs to come from somewhere. The crucial result of this thought experiment is that you cannot decrease the entropy of a system without increasing entropy somewhere else.
Also, "demon" is a classical way of talking about something that is making decisions and doing things in the background. If you run a *nix computer (OSx, linux, android, iOS), there are thousands of daemons running in the background, serving up your screen, counting the time, talking with the network, waiting for inputs, etc.
This example describes Maxwell's Demon, there's also Decartes' Demon, which you would probably identify with the machines in "The Matrix", there's Laplace's Demon, a thought experiment that disproves classical mechanics by pointing out that a demon that knows the position and speed of every particle in the universe knows the full past, present, and future. Morton's Demon is another word for Confirmation bias, the idea is there's a little devil that sits between your senses and your mind and only lets in information that already agrees with your beliefs.
It's interesting when you list the demons like that because all of those represent something that we are unable to do to create the conditions for a thought experiment except for Morton's Demon which is just there to simplify a conceptual layer of the thought process that actually exists. (a filter that favors information that fits into one's existing world view)
brilliant
the most part I loved is the thoughts energy 👍
Entropy never made sense to me until I saw the equation S = K*ln(w), which I simply read off as "entropy equals some constant times a function of possible particle/energy combinations". After seeing entropy equated to the number of combinations of particle and energy units, it made a lot more sense. Hopefully this super simplified explanation helps someone lost in the comments.
How does this demon relate to the osmosis phenomena and filtration techniques? Regarding the energy consumed by a thought or information bit, it's more easy to get a free lunch by the demon, than to get the right bit of information by oneself.
I like watching prof. Moriarty's video's, but they always leave me with more questions than answers. As he himself states, the content of the video is hugely simplified, but imho to the point where it is just confusing... like stating that the molecule is on the left or right side of the box is one bit of information. It might be, but the amount of energy I can extract also depends on the size of the box, the speed of the mocule etc. So this doesn't make the relation between energy and a bit of information clear at all! I am more confused now about what a basic bit of information is!
But ASSUMING all those other things are known, knowing about the position (at the which side of the box -level granularity) is exactly one additional bit of information.
You have to pick which bit of information is important for measuring the mars bars into "pieces of information" that we can use to get the answer for the question. He's giving a few differently examples of how you can think about what 1 bit of information of a piece of mars bar would be.
The information content for a single particle is whether the particle is or is not inside the box. If short it's a two-state system and its entropy in "nats" is ln(2) or (in appropriate units of energy divided by temperature) k*ln2. Then you just use the equation (which is not really applicable in this case but never mind).
E=TS
The temperature T is proportional to the average kinetic energy per particle, so for one massive particle in one dimension it's m(v^2)/2 so that's how you get everything to fit together, for a particle transferring some momentum onto the piston when it may or may not be there.
So one bit is about 0.02eV of energy. How would this actually translate to particle physics and a particle or a quantum state obtaining information? Seems it could have an effect.
Alternatively, will this ever be any kind factor in making computers? Probably not since even after 50 years of continuous Moore's law growth we would get to supercomputers storing a joule of energy as information. Not much...
The link to Moriartys blog says it has been deleted?
Do you have a valid link?
Could somebody explain why the second example doesn't work? The way Professor Moriarty explains it makes it seem like any kind of one way barrier is impossible to construct, am I misinterpreting?
Really though the "energy" of a Mars bar is actually more like the mass of the bar times c^2 if you were able to convert the entire bar into pure energy. So if you took half a Mars bar made of matter and half a Mars bar made of anti-matter (a Sram bar?) and stuck them together you'd release that much pure energy which you could then compare to the energy of a "thought" to see how many thoughts are contained in a Mars bar.
Nice drumstick piston
The partition/valve is just the thought accuracy of measurement at that moment. Concerning the demon it would know all movement/spin/trajectory/energy beforehand and can predict molecule movement. Almost like looking into the future.
Could someone explain why the gate and piston require no energy? Surely moving either would mean accelerating them, which at least given my knowledge of newtonian physics, would require a force and an input of energy.
Well, wouldn't the particle lose some of its energry on impact and therefore the overall energy of the system would be conserved?
Fun stuff again. So, I am musing about this. If one bit of information has 3x10 to the -21 Joules, and one picture of Dr. Moriarty has 1.5 x 10 to the -13 Joules, a thought in a human brain must take a lot more energy to receive, process, interpret meaning from, and remember. I know the Professor said we can't really calculate how much energy the thought has because we don't know enough about the brain yet, but still, wow!
So now I am wondering if the enery of a bit is used in the arguments about whether a black hole destroys information versus information can be retrieved. I think there is theoretical consensus on the answer, but I am going to wait a couple of hundred years and see what physicists say then.
The holographic universe idea must relate to the energy of information in some way too. The again, what is the connection between a bit and what is. Is the bit of information the object or describes the object? Is that too philosophical a question to ask in physics?
I feel weird understanding this, it's like Ive been shown a very blurry image and declared it to be crystal clear. I get the point of the video but I also understand I get nothing about entropy and its links to information.
What about the energy stored in the mass of the mars bar? e = mc^2 and all that? Anyways, I'd love to see more videos on this, the relation between something as physical as energy with something as abstract as information is fascinating to me.