23: Six Easy Pieces: Fundamental Physics by Richard Feynman
Hi there, One of my new year’s resolutions is to grasp the fundamentals of three majors: Physics, Biology, and Economics. I feel like I have a precarious foundation in these fields, and I don’t want my sand castle to collapse under its own weight through some challenges I might face ahead, so It is high time I fixed this and buckled down to buttress my castle. I am of the opinion that no time spent going back to the fundamentals is time lost so, that being said, here is my impression of Feynman’s first 6 lectures:
Feynman is one of the most inspiring physicists ever to have lived. His reputation precedes him among physicists and scientists alike. He is known for his insatiable curiosity, multidisciplinary approach, his onion layers of understanding, the Feynman method, and most importantly, his post mortem successful diagnosis of Challenger's failing.
This book is a series of Lectures on Physics taught at CalTech for first and second year physics students. In this lecture/book, Feynman kicks it off with defining the scientific method, how people get it wrong, and How science progresses.
Out of the blue, Feynman revs up the engine of his Physics magic bus and takes us on a tour to the very depths of matter, where he explains the Atomic theory, wherein the fundamental particles of matter are situated:
Everything is made of atoms. That is the key hypothesis. The most important hypothesis in all of biology, for example, is that everything that animals do, atoms do. In other words, there is nothing that living things do that cannot be understood from the point of view that they are made of atoms acting according to the laws of physics.
Looking out the window we can see electrons, neutrons, and a nucleus, and of course other particles like positrons, neutrinos, anti-particles, and all the rest wiggling and moving non-stop. But how do these particles interact, what hold them together?
there seem to be just four kinds of interaction between particles which, in the order of decreasing strength, are the nuclear force, electrical interactions, the beta-decay interaction, and gravity. The photon is coupled to all charged particles and the strength of the interaction is measured by some number, which is 1/137.
Here is an analogy to keep in mind that helps envisage the size of an atom:
if an apple is magnified to the size of the earth, then the atoms in the apple are approximately the size of the original apple.
From there, we move to magnetic forces, charges, electric forces, and the universal law of gravitation( Newton’s law of gravitation was updated by Einstein who added the limit of the speed of light) which governs the motion of planets all over the galaxy. On the way, we encounter the law of conservation of energy and the various different kinds of energy like potential,gravitational,electric,nuclear..etc. We then take a glimpse of all things orbital mechanics, Perpetual motion machines(?), Physics before 1920, Physics after 1920, the quest for unifying different theories and making physics simpler by forming amalgams of theories like electric+ magnetic, say. In another chapter, we see how Physics relates to all the other fields, from Biology to chemistry to geology to astronomy and all the rest.
At the end of the book we come face to face with one of the most mysterious theories of all: Quantum mechanics. We do a couple of thought experiments to try to understand Interference, how electrons, waves, and particles behaves, and why observation ruins everything. It all boils down to Heisenberg's Uncertainty Principle: If you wish to figure out where electrons pass through, you'd disturb the experiment, Interference will never occur, and you'll never know anything for certain. This is why physics can't predict the future; outcomes are just streams of probabilities.
Very much enjoyed this lecture; refreshed my memory and learned some stuff anew, thanks to Feynman's style. He makes you get excited about what he is talking about. It is not possible to read Feynman and not get infected with his enthusiasm and curiosity.
Some excerpts:
Strange as it may seem, we understand the distribution of matter in the interior of the sun far better than we understand the interior of the earth. What goes on inside a star is better understood than one might guess from the difficulty of having to look at a little dot of light through a telescope, because we can calculate what the atoms in the stars should do in most circumstances.
The ultimate basis of an interaction between the atoms is electrical. Since this force is so enormous, all the plusses and all minuses will normally come together in as intimate a combination as they can. All things, even ourselves, are made of fine-grained, enormously strongly interacting plus and minus parts, all neatly balanced out.
So the chemical properties of a substance depend only on a number, the number of electrons.
Proteins have a very interesting and simple structure. They are a series, or chain, of different amino acids
The stars are made of the same atoms as the earth.” I usually pick one small topic like this to give a lecture on. Poets say science takes away from the beauty of the stars—mere globs of gas atoms. Nothing is “mere.” I too can see the stars on a desert night, and feel them. But do I see less or more? The vastness of the heavens stretches my imagination—stuck on this carousel my little eye can catch one million- year-old light. A vast pattern—of which I am a part—perhaps my stuff was belched from some forgotten star, as one is belching there. Or see them with the greater eye of Palomar, rushing all apart from some common starting point when they were perhaps all together. What is the pattern, or the meaning, or the
why? It does not do harm to the mystery to know a little about it.
It is the nuclear “burning” of hydrogen which supplies the energy of the sun; the hydrogen is converted into helium.
The stuff of which we are made was “cooked” once, in a star, and spit out. How do we know? Because there is a clue. The proportion of the different isotopes—how much C12, how much C13, etc., is something which is never changed by chemical reactions, because the chemical reactions are so much the same for the two.
By looking at the proportions of the isotopes in the cold, dead ember which we are, we can discover what the furnace was like in which the stuff of which we are made was formed. That furnace was like the stars, and so it is very likely that our elements were “made” in the stars and spit out in the explosions which we call novae and supernovae.
Nobody in physics has really been able to analyze it mathematically satisfactorily in spite of its importance to the sister sciences. It is the analysis of circulating or turbulent fluids.
the conservation of energy. It states that there is a certain quantity, which we call energy, that does not change in the manifold changes which nature undergoes.
Statistical mechanics, then, is the science of the phenomena of heat, or thermodynamics. Inorganic chemistry is, as a science, now reduced essentially to what are called physical chemistry and quantum chemistry: physical chemistry to study the rates at which reactions occur and what is happening in detail (How do the molecules hit? Which pieces fly off first?, etc.), and quantum chemistry to help us understand what happens in terms of the physical laws.
We do much less well with the earth than we do with the conditions of matter in the stars
that there is no perpetual motion at all is a general statement of the law of conservation of energy.) We have to generalize the example where we moved only one weight to the case where when we lower one, we lift several different ones—but that is easy.) We call the sum of the weights times the heights gravitational potential energy—the energy which an object has because of its relationshipin space, relative to the earth.
Kepler’s three laws are:
I. Each planet moves around the sun in an ellipse, with the sun at one focus.
II. The radius vector from the sun to the planet sweeps out equal areas in equal intervals of time.
III. The squares of the periods of any two planets are proportional to the cubes of the semi major axes of their respective orbits:
Heisenberg’s Uncertainty principle:
one cannot design equipment in any way to determine which of two alternatives( Which hole the electron go through, that is) is taken, without, at the same time, destroying the pattern of interference.
The new view of the interaction of electrons and photons that is electromagnetic theory, but with everything quantum-mechanically correct, is called quantum electrodynamics. This fundamental theory of the interaction of light and matter, or electric field and charges, is our greatest success so far in physics.