What Constitutes Electrical Energy in an Infinite Electrical Field?

[leright]

But pete, energy is the capacity to do work!

Well, whatever. I am not interested in continuing this discussion. I don't go into the general discussion forum to discuss physics anyways.

edit: oh, this wasn't even in general discussion...my bad...well, I still don't want to discuss it right now.

 

[leright]

How would you explain that while this work is being done that the energy itself never changes.


Pete

The energy does change...work is simply the transfer of energy from one type to another.

I will just say that energy is an abstract concept...a mathematical construct used for bookkeeping...that is all.

 

[Rutherford]

Okay. I found some of y'alls more recent answers to be more helpful than the first few. And since you guys clearly aren't going to let this thread die, I guess I'll ask a more specific question.

When a fission reaction occurs, let's say it's a neutron colliding with a U-235 atom, kay?

Okay, so there's the U-235 atom with 92 protons and 143 neutrons. So then a neutron comes in an splits the atom, right? So now there are 92 protons and 144 neutrons. So then maybe the U-235 (which is now sort of a U-236) splits into a Kr-92 and a Br-141 and releases three neutrons plus energy.

So it has the same number of protons and the same number of neutrons in the end as it had in the beginning. Except that energy is somehow released. So my question is where does this energy come from? If none of the protons or neutrons are turned into energy or however you want to say it, then what is?!

 

[Cyrus]

http://en.wikipedia.org/wiki/Nuclear_fission

 

[pmb_phy]

I will just say that energy is an abstract concept...a mathematical construct used for bookkeeping...that is all.

That is almost exactly how Feynman put it.

Pete

 

[Xile]

Energy is used loosely, because every physical thing has energy. Mass energy, anything that's moving has more energy then something that's not. E=mc^2 even the great einstein himself saw it, energy is directly proportional to mass, they are one in the same. Although it does take quite a lot of force to convert mass into energy it can be done - but in general, every physical thing has mass-energy.

So, what is energy? Energy in one thing is related to 1.its mass and 2. its momentum, because einsteins 't-shirt equation' isn't E=mc^2, it is actually E^2=m^2c^4+p^2c^2 where p is momentum and E is energy-mass. The t-shirt equation is only used when the matter is not moving (ie p=0) and we call the E the rest-energy.

So to sum up - energy and mass are one of the same thing, energy and momentum are one of the same, BUT we don't always accept this in physics, for example, Newtons laws work perfectly for building bridges, for calculating motion equations, but theyre all wrong, however they are pretty damn close, einstein goes a step further and exaplains thigns exactly, but i wouldn't use his methods to build a bridge. We use energy to define a thing with no mass, and also we use it to describe the 'thing' that causes change. Eg energy causes something to move, to stop moving, to explode etc.

 

[pmb_phy]

Energy is used loosely, because every physical thing has energy. Mass energy, anything that's moving has more energy then something that's not. E=mc^2 even the great einstein himself saw it, energy is directly proportional to mass, they are one in the same.

I disagree. I believe it was the year after Einstein published his 1905 paper on E = mc^2 that he published another paper which shows that this relation is only true in certain special cases such as that of a closed system. E.g. it fails on a roid under stress.

For derivation please see

http://www.geocities.com/physics_world/sr/inertial_energy_vs_mass.htm

Pete

 

[rewebster]

Okay. I found some of y'alls more recent answers to be more helpful than the first few. And since you guys clearly aren't going to let this thread die, I guess I'll ask a more specific question...


...So it has the same number of protons and the same number of neutrons in the end as it had in the beginning. Except that energy is somehow released. So my question is where does this energy come from? If none of the protons or neutrons are turned into energy or however you want to say it, then what is?!

One of the problems with a question such as "What is energy?" is that 'energy' is a broad based term:


http://en.wikipedia.org/wiki/Energy_(disambiguation)


And if you just want to 'relate' it to science/physics, it is STILL broad based:

http://en.wikipedia.org/wiki/Energy#Forms_of_energy


http://en.wikipedia.org/wiki/Energy_(natural_science)


3 Regarding applications* of the concept of energy
3.1 Energy transfer
3.2 Energy and the laws of motion
3.3 The Hamiltonian
3.4 The Lagrangian
3.5 Energy and thermodynamics
3.6 Equipartition of energy
3.7 Oscillators, phonons, and photons
3.8 Work and virtual work
3.9 Quantum mechanics
3.10 Relativity

*Notice the terms 'applications' and 'concept'


and:


5 Forms* of energy
5.1 Potential energy
5.1.1 Gravitational potential energy
5.1.2 Elastic potential energy
5.2 Kinetic energy
5.3 Thermal energy
5.4 Electrical energy
5.4.1 Magnetic energy
5.4.2 Electromagnetic fields
5.5 Chemical energy
5.6 Nuclear energy


Notice the term 'forms' and how many there are.


And from:


http://en.wikipedia.org/wiki/List_of_energy_topics


"This is a list of energy topics which identifies articles and categories that relate to energy. In general, the energy refers to "the potential for causing changes". The word is used in several different contexts. The engineering use has a precise, well-defined meaning, whilst many non-technical uses often do not. In science and physics, it's a physical system's capacity to do work and this page contains items that are related to that definition."


AND:

http://en.wikipedia.org/wiki/History_of_energy



During a 1961 lecture[6] for undergraduate students at the California Institute of Technology, Richard Feynman, a celebrated physics teacher and Nobel Laureate, said this about the concept of energy:

“ There is a fact, or if you wish, a law, governing natural phenomena that are known to date. There is no known exception to this law—it is exact so far we know. The law is called conservation of energy; it states that there is a certain quantity, which we call energy that does not change in manifold changes which nature undergoes. That is a most abstract idea, because it is a mathematical principle; it says that there is a numerical quantity, which does not change when something happens. It is not a description of a mechanism, or anything concrete; it is just a strange fact that we can calculate some number, and when we finish watching nature go through her tricks and calculate the number again, it is the same. ”
—The Feynman Lectures on Physics[6]


So, for right now, it depends --some things about 'energy' are definable and other things aren't.

 

[leright]

Well, the way the KE and PE expressions are DEFINED due to electrostatic or gravitational potential is in terms of WORK. If an object has 5 joules of potential energy, that means the object can do 5 joules of work and if an object has 5 joules of kinetic energy that simply means if it came to a stop (perhaps due to a collision with another object) it does 5 joules of work to the other object.

This is how the mathematics are formulated.

 

[Cyrus]

Well, the way the KE and PE expressions are DEFINED due to electrostatic or gravitational potential is in terms of WORK. If an object has 5 joules of potential energy, that means the object can do 5 joules of work and if an object has 5 joules of kinetic energy that simply means if it came to a stop (perhaps due to a collision with another object) it does 5 joules of work to the other object.

This is how the mathematics are formulated.

You keep saying this, but I think everyone your talking to already knows this and is past freshman physics.

 

[leright]

You keep saying this, but I think everyone your talking to already knows this and is past freshman physics.

Well, that is the answer Cyrus. If they don't want to except the answer and insist on a deeper understanding then they are wasting their time.

Evidently some people do not understand the definition I am giving them and insist on thinking that the definition only applies to potential energy. Everyone understands work, and all of the energy equations are DERIVED with the idea that energy is the capacity to do work!

I'm not sure what the problem is here...

 

[Rutherford]

Well, how exactly does mass relate to energy in a non-mathematical way? I know that e=mc^2 and all that, but how does this mass get used as energy? And what happens to the mass after that?

 

[rewebster]

Well, how exactly does mass relate to energy in a non-mathematical way? I know that e=mc^2 and all that, but how does this mass get used as energy? And what happens to the mass after that?

Rephrase/paraphrase the question(s)----its not specific enough as it is.(please)



(for me, anyway--)

 

[pmb_phy]

Well, how exactly does mass relate to energy in a non-mathematical way? I know that e=mc^2 and all that, but how does this mass get used as energy? And what happens to the mass after that?

The energy is conserved. Some of it is locked up in mass-energy. This means that the forms of energy can change. So when a nuleus of an atom splits there is an increase in the total kinetic energy of the particles released. Also, when Einstein derived that equation for the first time he used "m" to refer to porper mass. He started out having the body release ennergy. He then showed that the release in energy came with a decrease in the proper mass of the emitting body. The amount of energy radiated E caused a decrease in proper mass of delta m. So delta E = delta mc^2.

That is the meaning of the equation. If you like I can show a website (mine of course) where I post several derivations of this relation. I ask first bercause it appears to me that people rarely read the references.

Pete

 

[marcus]

The thing is, we're talking about elementary particles here. Perhaps energy is the most elementary of all particles. Indeed, E does equal mc^2. Mass is energy. At some point, you can't ask what something is made of. It just is. You have atoms, which are made of nucleons and electrons, which are made ...

there is a paper by Laurent Freidel and Aristide Baratin
that illustrates a current direction in research examining the possibility that matter can be a facet of spacetime geometry

the thing is to get a dynamical model of the geometry
if it is a good model (like their spinfoam model tries to be) then it will contain matter fields (Feynman diagrams) which will appear out of the foam as you gradually turn gravity off.

I am not suggesting that you read the paper, which is technical. But you might like to know it (and others like it) exist.
http://arxiv.org/abs/hep-th/0611042
Hidden Quantum Gravity in 4d Feynman diagrams: Emergence of spin foams
Aristide Baratin, Laurent Freidel
28 pages
(Submitted on 3 Nov 2006, last revised 28 Mar 2007)

"We show how Feynman amplitudes of standard QFT on flat and homogeneous space can naturally be recast as the evaluation of observables for a specific spin foam model, which provides dynamics for the background geometry. We identify the symmetries of this Feynman graph spin foam model and give the gauge-fixing prescriptions. We also show that the gauge-fixed partition function is invariant under Pachner moves of the triangulation, and thus defines an invariant of four-dimensional manifolds. Finally, we investigate the algebraic structure of the model, and discuss its relation with a quantization of 4d gravity in the limit where the Newton constant goes to zero."

so you might imagine matter to be facets of geometry---microscopic "kinks" or "twists" in geometry some of which will cancel each other or react with each other---and which affect the surrounding geometry in the way we associate with gravity.
then to understand gravity at small scale would mean to understand the microscopic dynamics of spacetime geometry and matter.