The Crazy History of Quantum Mechanics | Leonard Mlodinow | TEDxJerseyCity

welcome to the loud and crazy history of quantum mechanics it's so crazy that it got Einstein here sliding off his chair and Niels Bohr biting his fingers and so that's what we're going to talk about today I'd like to talk about because I think it's important science is important society today and also if you're interested in science it's important to know how scientific discoveries are really made and there are a lot of lessons that you can get from science I think that you can apply in your everyday life and even some inspiration for instance science is more complicated than the myths portray Newton did not discover his physics by sitting in a field and watching an Apple fall and Darwin did not discover evolution by looking at the beaks of the finches on the Galapagos Islands in fact he didn't even know enough foreign ethology to know they were finches so that's all a myth and the way it really happened is much richer much more human and much more complex also most pioneer geniuses experience failure after failure before their success I find that inspirational too because in my life I've had many failures too and I know that if I keep going hopefully I'll get some success and you just have to hang in there scientists are often confused about their theories right up until the moment they complete them and even after they complete them and that's very important because of two reasons one it shows that these theories have a lot more to say than what meets the eye superficially so that even their discoverers don't understand them and it takes years to work out their implications but also because it shows you that it takes new generations people to have new ideas to new people coming into the field who aren't wedded to conventional beliefs into old old ideas and I think you can apply that in your life too rather than waiting for your children to improve your life after you're dead try and be open to new ideas while you're still alive and improve your own life and finally because of these things throughout science and also I think in business and in all our lives psychologists have shown that perseverance is the most important quality for success so let's talk about the first step of quantum theory quantum theory is the physics behind almost every technology that makes modern old what it is today computers communications technology cellphone the Internet it's all based on quantum theory and quantum theory itself was inspired or the road to quantum theory was begun by a technology of its day the light bulb which is why I'm showing Thomas Edison here and when the light bulb was invented scientists got interested in the properties of the light that's given off by things as they're heated they wanted to make better light bulbs and so they started studying how materials glow and they're heated and this is some experimental data that shows on this axis it's a little fuzzy but it's quantum theory so it's okay to be fuzzy it's uncertain it says wavelength there and so this is kind of the wavelength or the color of the light and visible range and the vertical axis shows you how much is given off at every wavelength so these are not theoretical curves this is experimental measured data and when physicists in the late 19th century tried to make physical models and apply Newton's laws and the laws of electromagnetic waves to to figure out how this happens to derive these curves they couldn't do it they got the wrong answer they got a totally absurd ridiculous result so nobody knew why materials behave like this so that was a big puzzle at the end of the 19th century now this guy Max Planck I like Max Planck because I have a complicated name Leonard Mladenov so when I make a reservation at a restaurant I say I'm max planck they don't usually spell it right but at least they can say it and they don't know who he is so that just shows you what good Fame in physics brings you you know but Max Planck was not did not set out to invent qualm theory he set out to find evidence against the existence of atoms so that also shows you how physicists how much they know about what they're doing okay but he set out to find evidence against atoms he thought he would could do that by explaining this blackbody radiation without using atoms there if I showing that atoms are worthless and the reason is that in 19th century the idea of using unseen objects in your physics was very new people thought the physics should describe stuff you can touch feel see and so a lot of people like Max Planck were against the idea of using atoms and so he tried to solve the blackbody radiation riddle without using atoms and for these three years he worked on it these are actually from newspapers of the day that I cut out on Google very nice fonts and and he say I'm as patient as he was and and he failed miserably so he worked on that for three years and got nowhere so at the end of that time he said let me change my goals this is also a good lesson let me let me be a little bit less ambitious and rather than looking for the physics behind these curves rather trying to explain where they come from using the laws of physics let me just see if I can find a simple mathematical formula that will that will describe these curves and he indeed did find that that's right they're called plumb the Planck law and it doesn't matter if you know any math it doesn't really matter what that says but what what's important is that that we call that a simple expression you might not if you didn't like algebra in high school but but on that that simple expression when you plug in numbers gives you this curve which is like it's labeled quantum here but if this is the actual experimental curve that the experimental was measured so he found this law he had no idea where it came from he just made up some mathematical formula that gives us curve meanwhile physicists had this law I mentioned it earlier they applied Newton's laws and they tried to derive the law and they got this crazy result that's called classical here that was done by a guy named uh Lord Rayleigh and Sir James genes and it doesn't work at all but that's the law that the theory that's the law that this is the law that flag says happened but he didn't know where it came from so we were in a funny situation where we had a theory that predicted something that was wrong and we had a mathematical law that would that that showed that correspondence a data but we had no idea where it came from this is how physicists work what can I say so what happened next Planck his everlasting credit decided that he should be open-minded and forget about his antipathy toward atoms and use atoms to derive the law and he was almost successful but he found he needed one little other really weird ingredient again showing how open-minded and adventurous he was okay he he realized from the mathematics that that he could only derive the law if he constrained atoms to having only certain possible energies so in life many things come in continuous form like water you can fill up a glass to any level you want of water but if you have jellybeans you can only put them in one at a time you could have one two three you can't have one point three seven six jellybeans so physicists thought that most the colonies in nature were continuous like the water but now they realize well they didn't realize this but but Planck was saying that for atoms it could only have certain pot certain discrete levels of energy and if I make that assumption I can explain the blackbody radiation so what was the reaction well there was a whole spectrum of reaction to this no one thought that this was a new law of nature and he had discovered hey max congratulations you discovered quantum theory the people who are most positive said okay you made this weird assumption you derive the answer there's something to what you're saying and we congratulate you because you can derive the answer and we'll eventually figure out what it means and the other end of the spectrum said this is all garbage and in fact sir Sir James Gene's was one of them he's one responsible for this law and he basically said my law doesn't work in yours does but I like mine better which I think illustrates what Robert Frost said why abandon a belief merely because it ceases to be true so as you can see physicists were not exactly clear about what's going on so next Along Came Albert Einstein for five years not one single paper was written about Planck's quantum idea then this kid well a twenty-something at the time then Einstein comes along and he says hey max you didn't just explain blackbody radiation but your quantum idea is a fundamental principle of nature and in fact you shouldn't just apply it to atoms we should apply it to light as well so you know we think of light as being like water that can have any amount energy or people used to think that because they thought it was a wave and Einstein said just like a water wave it's which is made of little atoms you're waves of light are made of these little particles called photons and so the amount of energy in a light beam can only have certain discrete values now I get a lot of theories like this in my gmail all the time you know people say hey look at my theory it's a beautiful theory it's a crazy theory you know I don't know things like the earth is really a living organism it's alive it Mars is its sister if you sit under a crystal you'll cure cancer I mean Credo you're laughing but but this didn't look any more reasonable to physicists of the day than what I'm telling you now but what I incentives go one step further which is very important in science and he applied it to explain something and what he explained is called the photoelectric effect doesn't matter what that is you know I'll just tell you that that's when you shine light on certain metals they give off electric electrons or an electric current and this is like blackbody radiation in that it could not be explained by using classical laws physicists had applied the laws of classical physics to this system and they found that they got the wrong answer Einstein with his idea of quantized light and photons was able to explain this that's what he ended up getting a Nobel Prize for and the 19th and I think was 1921 so this was a big deal that he could explain this but the reaction of physicists was the same as it was to Planck good Einstein I'm glad you could explain this we don't believe this photon crap will eventually figure out what it really is but okay it's something that explains this so the best reaction was from Planck who when he was recommending Einstein for the Nobel Prize said I'm Stein has done a lot of good things so please excuse him for stupid ideas like this Photon now that's really interesting because because Einstein was really saying the Planck's work was more important than people thought but Planck was saying no it's not the next step came from Niels Bohr the guy who was biting his nails up there this was in 1912 again Bohr was a kid just out of college he liked Planck's theory he liked Einstein's theory he said let's combine them let's take a quantum theory of light and the Planck's theory of atoms and what happens we put them together and when you put them together what he came up with it was a model where that were the atom we can all you may recognize as we call the Bohr atom where the atom has these discrete energy levels and single photons can come in or be emitted and cause the electrons to jump around there and using this model he was able to explain what's called a spectroscopy of elements so people have known for decades that certain elements give off certain discrete kinds of light when they're heated like if you take a penny and you put it in fire it glows green it doesn't glow orange or yellow or rainbow it just glows green and it also gives off other frequencies you can't see and why do it does each element have a characteristic set of frequencies that it gives off Bohr was able to numerically derive that using his theory so again great thing no one cared okay so so now they said okay Niels you to have explained another ad hoc physical phenomena using these crazy ideas and eventually we'll figure it out and let's just move on and it was another 12 years and I'm sorry the reaction well that's what I just told you my favorite one was Arthur Eddington who said quantum theory is a crazy german invention oh this guy - he was a spectroscopy whoo-hoo it's really his work Bohr was explaining his measurements he says it was regrettable that the literature should be contaminated by such wretched information betraying so much ignorance so that was the reaction nineteen twenty five and twenty six these guys came along that is Heisenberg Verner Heisenberg if you google Heisenberg you're going to get Walter Heisenberg okay as a physicist again I take offense at that but you can be a you know a star of a TV show for a couple years and you displace the founder of quantum theory from the first pages of Google but this is very rare Heisenberg who Walter actually in the show named himself after but got the first name wrong but we can understand that because who knows physics anyway so these guys came up with really the final step in the development of quantum theory I mean we've developed it further since but this was the big step because they didn't just explain discrete phenomena using ad hoc assumptions they came up they each came up with a theory a quantum theory that you could use to replace a Newton's laws so this is a physical theory that could in principle be applied to any system to tell you the quantum properties of that system the problem was that Heisenberg Theory was hard to understand and no one liked it because it had to do with things we couldn't observe Schrodinger in fact read it and said it was disgusting and came up with his own theory competing theory which used waves which is also strange because kalam theory is strange but people liked it better because they were more familiar with waves and Heisenberg crazy matrices and things like that well it was shown that the theories were actually equivalent when they was shown that they were equivalent Schrodinger reacted very badly he said he wouldn't have even come up with his theory if he knew that it would be equivalent to Heisenberg's theory he was trying to refute Heisenberg's theory but the interesting thing was guess who showed that they were equivalent it was shorting her himself so so he actually was trying to show that his theory was superior to Heisenberg's when he discovered that they were identical but being a good scientist he published that anyway and just groused about it Einstein as you all know didn't like alarm theory at all because it turned out even though he was one of the inventors as it developed it turned out that it has these probabilistic interpretations so he didn't like it and finally I'm what did Heisenberg say Heisenberg said that Schrodinger's version is a bunch of crap okay so this is how physics is really done I wanted to make sure that I got that out yeah and it's a lot like life is really done but in the next decades it's been about nine decades since then quantum theory has become the most successful theory in the history of science and as I said modern life is really based on quantum theory just to show you how its advanced this is the helium atom it has a proton and two electrons and that's an equation for from the 1920s and today we have we know a lot moral element repower coils in the proton the electron and is what the equations look like and so these are the equations for what's called the standard model that you know the Higgs boson is part of that that we just discovered and things have gotten a lot more complicated and a lot more advanced in the last decades and our laboratories have - they've gone from tabletop simple tabletop systems to stuff like this which is the Large Hadron Collider in in Geneva and Switzerland so if you want to know more you can look at my book The Upright thinkers which talks about the human journey from when we were eight to now only understand the cosmos and I try to to emphasize the social and cultural connections between science and human life in general and that's it thank you very much you

Channel: TEDx Talks

Views: 41,936

Keywords: TEDxTalks, English, United States, Science (hard), Life, Physics, Rocket science, Science

Id: oQYsqnRYb_o

Length: 15min 57sec (957 seconds)

Published: Mon Feb 08 2016