BaalChatzaf Posted June 13, 2014 Share Posted June 13, 2014 In a simple DC circuit power by (say) a 12 volt battery, electrons move at about 8.5 cm/hour (!!!). That is right kiddies, about 4 inches an hour. Yet when you flip the switch or close the circuit if a light bulb is in the circuit it turns on instantly (the energy from the battery reaches the bulb at a substantial fraction of the speed of light). The Riddle:; how is this possible?I know the answer and I will tell you in due course. I am willing to bet some of you have images of garden hoses and water running in your heads. Ba'al Chatzaf Link to comment Share on other sites More sharing options...
Wolf DeVoon Posted June 13, 2014 Share Posted June 13, 2014 A row of billiard balls. Link to comment Share on other sites More sharing options...
SoAMadDeathWish Posted June 13, 2014 Share Posted June 13, 2014 Well electrons are not the same thing as the electromagnetic field that carries the current, so it's really not all that surprising. Did I get it right? Cool riddle.But I have a good one too.How does the gravity get out of a black hole? Link to comment Share on other sites More sharing options...
syrakusos Posted June 13, 2014 Share Posted June 13, 2014 The change in potential is instantaneous (speed of light). Once the potential is reached, then the crawling begins. Link to comment Share on other sites More sharing options...
BaalChatzaf Posted June 13, 2014 Author Share Posted June 13, 2014 A row of billiard balls.What billiard balls? The electrons in a copper conductor (say) do not constitute a rigid body. In fact there are no totally rigid bodies in nature (because of their atomic make up). Try again.Ba'al Chatzaf Link to comment Share on other sites More sharing options...
BaalChatzaf Posted June 13, 2014 Author Share Posted June 13, 2014 The change in potential is instantaneous (speed of light). Once the potential is reached, then the crawling begins.Nope. The light goes on instantly (speed of light or very close to it). With electrons moving in the conductor at 4 inches an hour this would not happen. Link to comment Share on other sites More sharing options...
BaalChatzaf Posted June 13, 2014 Author Share Posted June 13, 2014 Hint. The lighting of the light (or heating of a resistor) is the result of a field effect.Ba'al Chatzaf Link to comment Share on other sites More sharing options...
BaalChatzaf Posted June 13, 2014 Author Share Posted June 13, 2014 Here is an elementary explanation of simple circuits as field effects. The math is lite, but it seems to cover the ground.http://www.abc.net.au/science/articles/2014/02/05/3937083.htmhttps://van.physics.illinois.edu/qa/listing.php?id=20654And this is a fine rant against the way electric circuits are taught in elementary school:http://amasci.com/miscon/energ1.htmland yet another rant. http://amasci.com/miscon/ener1.htmlNo wonder the U.S. is 20 th in the world in science education. It is all done with Poynting Vectors. Have a look here: http://en.wikipedia.org/wiki/Poynting_vectorThis paper is a gem and it is not Math Heavy: http://science.uniserve.edu.au/school/curric/stage6/phys/stw2002/sefton.pdfBa'al Chatzaf Link to comment Share on other sites More sharing options...
tmj Posted June 13, 2014 Share Posted June 13, 2014 I can't explain the phenomenon in a precise scientific sense, though it has to do with flow of charge through a material that somehow results in emitting photons which are somehow a byproduct of electron inter(intra)? -actions.To me the possibility isn't a riddle, the riddle is why does it happen every time. Link to comment Share on other sites More sharing options...
Wolf DeVoon Posted June 13, 2014 Share Posted June 13, 2014 A row of billiard balls.What billiard balls? The electrons in a copper conductor (say) do not constitute a rigid body. In fact there are no totally rigid bodies in nature (because of their atomic make up). Try again.Ba'al Chatzaf "Quantum billiards is a game played by physicists at a few academic and industrial laboratories in various parts of the world....The billiard balls I have in mind are the electrons. You should know that the motion of an electron in a typical metal wire does not resemble at all the rectilinear motion of a billiard ball. The impurities in the metal scatter the electrons in all directions, so that the motion becomes completely unpredictable. One speaks of a "random walk". A measure for the influence of impurities on the electron motion is the so-called 'mean free path'." [Carlo Beenakker, Univ of Leiden]"from the perspective of quantum field theory, the field is seen as quantized, being composed of individual particles." [Wikipedia] Link to comment Share on other sites More sharing options...
BaalChatzaf Posted June 13, 2014 Author Share Posted June 13, 2014 A row of billiard balls.What billiard balls? The electrons in a copper conductor (say) do not constitute a rigid body. In fact there are no totally rigid bodies in nature (because of their atomic make up). Try again.Ba'al Chatzaf "Quantum billiards is a game played by physicists at a few academic and industrial laboratories in various parts of the world....The billiard balls I have in mind are the electrons. You should know that the motion of an electron in a typical metal wire does not resemble at all the rectilinear motion of a billiard ball. The impurities in the metal scatter the electrons in all directions, so that the motion becomes completely unpredictable. One speaks of a "random walk". A measure for the influence of impurities on the electron motion is the so-called 'mean free path'." [Carlo Beenakker, Univ of Leiden]"from the perspective of quantum field theory, the field is seen as quantized, being composed of individual particles." [Wikipedia]It is not the electrons that carry the energy. The motion of the electrons produce the magnetic field. The Poynting vector (field) is produced by an interaction of the electrical and magnetic fields surrounding the circuit which acts as a wave guide.The lighting of the bulb or heating of the resistor is a field effect.The electrons move so slowly that they do not possess enough kinetic energy to heat up the wire. Have a look at the elementary items I posted. Ba'al Chatzaf Link to comment Share on other sites More sharing options...
Mikee Posted June 13, 2014 Share Posted June 13, 2014 At any given instant very small percentage of electrons contained in the atoms of the conductor are jumping from one atom to an adjacent atom because of the applied field potential. The distance of these jumps is miniscule; the distance between one atom and the next. There are field interactions between the moving electrons and the positively charged atoms, these are the forces that cause the movement of the atoms, the kinetic energy increase we detect as heat. The net drift of electrons along the conductor is slow if you divide by the total electrons contained in the conductive material only a tiny percentage of are actually in motion at a given time. The jumps are very small and it takes trillions of them to move an appreciable distance along the wire. But individual electrons are moving very fast when they jump from one atom to the next. Link to comment Share on other sites More sharing options...
BaalChatzaf Posted June 13, 2014 Author Share Posted June 13, 2014 At any given instant very small percentage of electrons contained in the atoms of the conductor are jumping from one atom to an adjacent atom because of the applied field potential. The distance of these jumps is miniscule; the distance between one atom and the next. There are field interactions between the moving electrons and the positively charged atoms, these are the forces that cause the movement of the atoms, the kinetic energy increase we detect as heat. The net drift of electrons along the conductor is slow if you divide by the total electrons contained in the conductive material only a tiny percentage of are actually in motion at a given time. The jumps are very small and it takes trillions of them to move an appreciable distance along the wire. But individual electrons are moving very fast when they jump from one atom to the next.the individual electrons are moving about 4 inches an hour in the wire. The energy is carried in a field whose direction is indicated by the Poynting vectors. Read the references I provided. The movement of the electrons are producing the magnetic field which interacts with the electric field that is moving the atoms (albeit slowly) The cross product of the magnetic field and the electric field produces the Poynting vectors. The energy gets from the battery to the resistance through space. The energy made by the battery to produce the electric field is exactly equal to the energy produced (mostly as heat) from the resistance. Energy is conserved. The Energy is actually broadcast. have a look at this diagram to get the idea: http://www.abc.net.au/science/basics/img/electriccircuits.jpg The idea that electrons move through the wire like water through a hose and that motion carried the energy to the resistance is bogus. If you were powering a circuit from a generator located a hundred miles away from you how long do you think the generator would take to shove electrons through your circuit at home? Considering they move at 4 inches an hour. Ba'al Chatzaf Link to comment Share on other sites More sharing options...
Mikee Posted June 13, 2014 Share Posted June 13, 2014 It would be helpful if you read what I wrote Bob. Where did I say the electrons move like water through a hose? Nevermind, I don't have time for your games. Link to comment Share on other sites More sharing options...
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