Talk:Energy

Definition

This article begins In physics, energy is a scalar physical quantity that describes the amount of work that can be performed by a force. On 21 April 2009 User:Wisnuops (talk) added the following comment:
(note: this is not the best definition. The word work is also defined by referring to energy. It creates a circular definition).

I have deleted the note from the article and transferred it here. It may stimulate debate. Dolphin51 (talk) 03:58, 22 April 2009 (UTC)

At the beginning definition it mentions forms of energy and lists Kinetic, Potential, Light, Elastic, Electromagnetic etc. Isn't Light already Electromagnetic Energy via the Visible Light part of the spectrum? If so this is redundant. Gheta (talk) 19:10, 22 July 2009 (UTC)

I agree that electromagnetic energy includes visible light. Dolphin51 (talk) 23:55, 22 July 2009 (UTC)

Currently the first sentence no longer has a reference to work. Though this avoids the circular definitions of energy and work, it leaves us with energy defined simply as "a quantity that can be assigned to every particle, object, and system of objects as a consequence of the state of that particle, object or system of objects". This definition doesn't seem satisfying. Does it distinguish energy from other state functions such as entropy? I'm not really convinced that the following two statements constitute a circular definition rather than merely reflecting the fact that energy and work are intertwined: Energy is the amount of work that can be performed by a force. Energy is transferred when work is performed. —Preceding unsigned comment added by Davidr222 (talk • contribs) 18:54, 14 April 2010 (UTC)

If scalar means single dimensional Energy is not a single dimensional quantity. It is related as to how a quantity of matter is or potentially can be be made to be moved a certain spacial volume quantity within an interval of time. When the time period is over, a quantity of action will have occurred, involved with the matter's having been converted to the same quantity of a new kind of action. If the process is inefficient waste values of lost action will be created and lost, and the quantity of available future action is reduced. So Energy is action per unit time interval and action is Energy times time. So when you carry things upstairs to store in the attic, you're doing a lot of work without being able to regain any of the potential action contained in the stored materials due to their higher gravitational location.WFPM (talk) 04:38, 15 April 2010 (UTC)

Coming up with a simple definition of "energy" is not possible, but I admire the author for trying. I agree with Davidr222 completely. The statement that energy is a quantity that can be "assigned" to various examples of matter is not helpful and does not make sense if you think about it. "Quantity" refers to a value that is used to describe the amount energy. The energy is not the quantity, just like me standing on the scales is not the weight. I also do not understand what "assigned" means in the context of the definition. Assigned is passive, meaning somebody has to do the assigning. But the energy is present regardless of any assigning body or person. So I don't think one can defend the statement that energy is " a quantity that can be assigned." BabelBoy (talk) 01:30, 25 April 2010 (UTC)

Sorry to be so bothersome, but I am also having problems with this statement:

"As an example, when oil is reacted with oxygen, potential energy is released, since new chemical bonds are formed in the products which are more powerful than those in the oil and oxygen. "

First, grammatically, it should read either: ". . .products, which are more powerful. . ." (note the comma) or ". . .products that are more powerful. . ." They are two entirely different statements. In the original we can't tell whether it is the bonds or the products that are more powerful.

My second problem is I have no idea what the sentence is saying. "Oil" is awfully vague. Does the author mean hydro-carbons? The product of the sebaceous glands? Baby oil? Shouldn't "oil" be linked to the Wiki article "Oil?" Also, what is meant by "more powerful"? Contains more energy? But that's what we're defining.

Third, the phrase "potential energy is released" is set off by commas, which really distorts something. Is the author trying to say that the release of potential energy [whatever that means] is a consequence of reacting oil and oxygen? BabelBoy (talk) 01:51, 25 April 2010 (UTC)

Circular Definitions

Either the work page or this should change definitions in the introductions. As it is, a curious individual, or perplexed student, comes to the energy page to see the definition of energy: Energy is a scalar physical quantity that describes the amount of work that can be performed by a force. Fair enough, so the inquisitive student will ask..."hmm, what's work?" being wikipedia one can conveniently click on the link, unfortunately one finds in the introduction: mechanical work is the amount of energy transferred by a force acting through a distance. It may make sense in the equations, but verbally it seems circular. 76.175.72.51 (talk) 04:22, 18 October 2009 (UTC)

"Different forms of energy include kinetic, potential, thermal, gravitational, sound, elastic, light, and electromagnetic energy." Small correction: Light and electromagnetic energy are the same. —Preceding unsigned comment added by 86.176.242.199 (talk) 13:25, 2 March 2010 (UTC)

Took out table "Magnitude comparison of different forms of energy"

I took out this table as potentially misleading. A form of energy doesn't have a magnitude. I guess it could be called "magnitudes of coefficients of equations for energy", but that doesn't seem like a meaningful or useful comparison. We already have the article Orders of magnitude (energy). --Suffusion of Yellow (talk) 08:24, 22 October 2009 (UTC)

Confusing list of forms

This sentence from the intro:

"Different forms of energy include kinetic, potential, thermal, gravitational, sound, light, elastic, and electromagnetic energy."

is, in my opinion, poorly worded - even if it is technically true that each of those words can describe some form of energy. Kinetic and potential are a totally separate categorization of energy - in its current shape, the sentence can easily convince someone that thermal is something completely different from kinetic. Or, taken with the next sentence The forms of energy are often named after a related force., it could be taken to suggest that some sort of a "kinetic force" exists.

I suggest we remove the 'kinetic' and 'potential' words from that particular sentence - if we want to have a reference to them in the intro, we can add a sentence along the lines of 'Energy is often split into kinetic and potential' Ivancho.was.here (talk) 03:34, 11 December 2009 (UTC)

Kinetic and potential could be Mechanical. Grvitational could be removed, since gravity is a force and I'm pretty certain that it's called potential gravitational. Busha5a5a5 (talk) 18:18, 15 February 2010 (UTC)

Can "Energy" have a purely abstract, non-physical meaning?

I suggest that semantically, the word energy can have a purely abstract non-physical meaning, as "something that moves" (something else or itself), in any kind of reference system.

For example, one could say that there are "energies" in the psyche, in the sense that there are psychological motives or mechanisms that activate/move the psyche in a certain direction, or which inhibit and block certain other tendencies in the psyche.

There is no reason why the notion of energy should be the exclusive property of physical sciences. The purely abstract use of that word in any kind of reference system is perfectly legitimate. —Preceding unsigned comment added by 161.53.149.242 (talk) 15:36, 19 January 2010 (UTC)

Dictionaries don't like it when you attach a nonrational meaning to a word. So if you don't know the rational connotation of a word like Energy why would you use it in an attempt to communicate? Therefor when you say that the psyche has energies, you are making a misstatement, because the connotation of Energy is that it is the result of something rather than the cause of something.WFPM (talk) 15:47, 15 April 2010 (UTC)

The top of the page reads This article is about the scalar physical quantity. For other uses, see Energy (disambiguation). What else do you want? ― ___A._di_M. (formerly Army1987) 16:09, 15 April 2010 (UTC)

I'm guessing you're answering me, so I am ranting about the use of the word Energy as a play on words. That's because Energy is connoted as being the result of an activity of matter or pseudomatter by causative factors and therefor is a resultave condition of the matter or pseudomatter. It doesn't cause anything in physics concepts, except for some activity to be initiated as the result of the accumulation of enough action to permit it. So matter (or pseudomatter) cannot receive energy and accumulate action and have something happen unless causative factors are considered. Thus the arguments about nuclear decay processes and chemical processes and Enzyme activity etc etc. In short I'm trying to keep the logic of cause and effect straight about the use of the word Energy.WFPM (talk) 19:15, 15 April 2010 (UTC)

No, I was answering the OP. (Anyway I would not be surprised if the non-physical meaning of energy was actually older than the physical one, as is the case for power and speed. That's irrelevant to which is the primary meaning today, anyway.) ― ___A._di_M. (formerly Army1987) 19:25, 15 April 2010 (UTC)

Well before Newton it was speculated the force was required to keep things moving. But He invented the idea that if the thing had energy or really action, it would keep moving on its own. But it still wasn't a separate thing from the involved matter but rather a physical motion property that the thing had acquired relative to space and time. So it's hard to dream up a concept of Energy apart from matter, or that it can do anything other than influence matter by its level of Energy delivery capability.WFPM (talk) 21:12, 15 April 2010 (UTC)

And I appreciate your information about metaphors. But like Art Ls Pella said about stock trading, Understanding the words of science is serious business and it's getting harder and harder to rationalize and understand the complex details. And I'll bet that a PC using Boolean logic and algebra will never get it figured out.WFPM (talk) 21:30, 15 April 2010 (UTC)

Automate archiving?

Does anyone object to me setting up automatic archiving for this page using MiszaBot? Unless otherwise agreed, I would set it to archive threads that have been inactive for 30 days and keep ten threads.--Oneiros (talk) 13:45, 24 January 2010 (UTC)

 Done--Oneiros (talk) 00:27, 1 February 2010 (UTC)

That reminds me that Dr Pauling commented about his arriving at opinions about chemical and other subject matters that "I think about things a lot!" So I admire your concise editorial capability to tell a computer program about how to judge the editorial importance of what it needs to keep printing about a subject matter.WFPM (talk) 02:34, 16 April 2010 (UTC)

Energy

What is energy? —Preceding unsigned comment added by 218.103.199.177 (talk) 14:32, 28 January 2010 (UTC)

Energy in itself is non-existing as explained by Richard Feynman in his Dennis the Menace blocks lecture; "There are no blocks!". Energy is born into existence once manifestated in a certain form, hence "different forms of energy". The law of conservation of energy does not formulate energy but is a law which relates to other theories in physics that do give a formulation of energy, hence the law of conservation of energy is a metatheoretical law. --Knoxjohnson (talk) 12:32, 21 March 2010 (UTC)

Energy is a 3 dimensional entity measurement of the relative magnitude of importance of the activity of matter within the spacetime continuum. In the dynamic sense, the measurement relates to the rate of displacement of the matter within the (3 dimensional) space continuum. In the static case the magnitude is predetermined by mathematical predictive calculations. One of the magnitude's dimensions is related to it's mass value, and the other two to a two dimensional value that is related to the volume of spacial displacement of the matter per unit of spacial distance. The equality equation for energy is therefor E is proportional to the mass value times S cubed divided by S. This concept of energy of course implies that in order for something to have energy, it must first have matter.WFPM (talk) 12:58, 14 April 2010 (UTC)

I don't doubt the accuracy of what you have written. What is required in this Wikipedia article, and certainly in the lede section of the article, is an explanation that a teenager with a genuine interest in finding some answers will find meaningful. Developing an explanation that is meaningful to the general English-speaking public is usually more difficult than developing a thoroughly rigorous explanation that is meaningful to a College professor. Dolphin (talk) 13:06, 1 April 2010 (UTC)

Well, in this modern age of nonmaterial entities, it's hard to to explain to anybody, particularly a teenager about real physical entities. And so I'm trying to explain that there aren't any nonmaterial things and that every thing has to have matter and that its energy content is related to its rate of space volume displacement. And of course I'm getting shot full of holes by theorists who don't believe that. Like that the force of gravity is proportionate to the number of nucleons regardless of how they're arranged etc. And that each molecule of a gas is bouncing up and down within its container with a varying velocity such as to provide the differential atmospherical pressure causing buoyancy, etc. And the net result is that unless you look for and find someone who likes to explain things on a basic level, like Dr. Isaac Asimov used to do, you now have to be educated up to almost the college level before you can understand the explanations.WFPM (talk) 14:36, 14 April 2010 (UTC)PS for a concept of what an atomic nucleus might look like as a real physical entity see Talk:Nuclear model.

So we've got this problem of dichotemy in physics that allows things like the photon to be described as a massless particle that transports "packets" of energy over long distances that keeps things confused even for the experts of which I am not one. And until that gets straightened out, I'm afraid that the teenager will have to muddle along with the rest of us.WFPM (talk) 16:34, 14 April 2010 (UTC)

Energy is not a scalar in special relativity

Energy is of course a scalar quantity in classical (non-relativistic physics); but it special relativity it is the time-component of the momentum four-vector and obviousley not a scalar. I think the opening lines of the article should be corrected this way: " in non-relativistic physics, energy is a scalar quanity". We then need to say, somewhere else that in relativity energy is only a component of a vector This is directly related to the celeberated E=mc^2. 95.82.51.176 (talk) 00:19, 1 February 2010 (UTC)

Well, TIME is a scalar quantity in classical physics, but can be regarded as a vector (or vector-space) in relativity. So what? It is of no help in understanding the nature of time, except to remind us that when the spacial quantities increase, the time-like thing decreases. If we want to use energy and momentum to calculate anything in relativity, such as the scalar invariant mass, we strip them of their vector properties and use the Minkowski norm, or 4-vector length. Here energy and net momentum subtract from each other as squares, followed by a root, just as would happen for the length of the vector connecting two perpendicular vectors. But the answer is not a vector. SBHarris 01:14, 9 February 2010 (UTC)

Example in second paragraph seems to be inaccurate

"When oil, which contains high-energy bonds, is burned, the useful potential energy in the oil is converted into thermal energy, which can no longer be used to perform work (e.g., power a machine) and is lost. Although the thermal energy may not be a useful form of energy, the total energy has remained the same."

Converting chemical energy to thermal energy is exactly what does produce the work. For instance in an internal combustion engine it is the thermal energy that causes the gases to expand and move the pistons. Also in a thermoelectric system it is the thermal energy that gets converted into electrical energy. Only where there is very low grade heat energy, not much higher in temperature relative to its surroundings, is thermal energy no longer able to perform work. --CharlesC (talk) 12:07, 13 February 2010 (UTC)

This article is about the scalar physical quantity. For other uses, see Energy (disambiguation).

Lightning is the electric breakdown of air by strong electric fields and is a flow of energy. The electric potential energy in the atmosphere changes into heat, light, and sound which are other forms of energy.In physics, energy (from the Greek ἐνέργεια - energeia, "activity, operation", from ἐνεργός - energos, "active, working"[1]) is a scalar physical quantity that describes the amount of work that can be performed by a force, an attribute of objects and systems that is subject to a conservation law. Different forms of energy include kinetic, potential, thermal, gravitational, sound, elastic, light, and electromagnetic energy. The forms of energy are often named after a related force.

Any form of energy can be transformed into another form, e.g., from potential to thermal, and dissipated into the atmosphere. When oil, which contains high-energy bonds, is burned, the useful potential energy in the oil is converted into thermal energy, which can no longer be used to perform work (e.g., power a machine) and is lost. Although the thermal energy may not be a useful form of energy, the total energy has remained the same. The total energy always remains the same whenever energy changes from one form to another, even if the energy loses its ability to be used for performing work. This principle, the conservation of energy, was first postulated in the early 19th century, and applies to any isolated system. According to Noether's theorem, the conservation of energy is a consequence of the fact that the laws of physics do not change over time.[2]

Although the total energy of a system does not change with time, its value may depend on the frame of reference. For example, a seated passenger in a moving airplane has zero kinetic energy relative to the airplane, but non-zero kinetic energy relative to the Earth —Preceding unsigned comment added by 217.78.49.201 (talk) 18:49, 22 February 2010 (UTC)

Yes, it's wrong. Some of the thermal energy can be converted to other kinds of energy, and the rest cannot, according to the second law of thermodynamics. If it's never converted to thermal energy in the first place (as in a fuel cell) you don't have to deal with this problem, and efficiencies can be far higher (in theory, 100% if you never produce any heat). Also, there is no such thing as a "high energy bond", in a sense of a bond that gives energy when broken. That idea is a corruption of (bad) language which has crept in from biochemistry (you can see me fulminating about it on the ATP talk page, in fact). The "energy" is not in gasoline or its bonds, but in the gasoline-oxygen system. It results from making bonds more powerful in H2O and CO2, than those that are broken in the gasoline and oxygen. I'll see what I can do with the second paragraph. SBHarris 19:07, 22 February 2010 (UTC)

Energy in itself

Energy in itself is non-existing as explained by Richard Feynman in his Dennis the Menace blocks lecture; "There are no blocks!". Energy is born into existence once manifestated in a certain form, hence "different forms of energy". The law of conservation of energy does not formulate energy but is a law which relates to other theories in physics that do give a formulation of a certain form of energy, hence the law of conservation of energy is a metatheoretical law. The article appears to remain a bit unclear about the relationship between "energy" and "forms of energy".--Knoxjohnson (talk) 12:45, 21 March 2010 (UTC)

"Any form of energy can be transformed into another form" or "Any form of energy can be transformed and can only be transformed into another form"? --Knoxjohnson (talk) 12:50, 21 March 2010 (UTC)

You have misunderstood the lecture. When Feynman says there are no blocks, he means there are not natural divisions that break energy up into natural blocklike components. Thus, no natural energy "units." He is NOT saying there is no such thing as energy, just that it's not quantized in fundamental blobs that we can count. We can use any number we like, and any units we like. Whatever units we use, we get a number which is conservered over time. The actual number isn't important-- only the fact that it doesn't change is important. It's sort of like money-- we don't care what the denomination or currency is-- we only care that none is missing from the vault. Feynman is saying there are no particular bills, no particular coins, in nature. He's not saying there's no money, no value. SBHarris 01:01, 3 April 2010 (UTC)

Hmmm… The analogy with money is quite interesting because it is capable of demonstrating two possibilities. An amount of gold can be melted and formed into a collection of coins. Each coin will, because of its shape and size, have a precise weight which determines the value of the coin and this value can be displayed upon the coin. In the end of the day it is the essence of the coin, the gold, which is responsible for its value and the form of the coin represents this value (assuming that the coin is not a collector’s item). Money nowadays appears to be almost virtual, just numbers on a screen which are empty from any essence. Can energy in itself be compared with the gold of the coin or can it be compared with the abstract numbers empty from essence?

The page 'energy' gives a description of what energy is and then the page talks about "Different forms of energy". If the understanding of the term "Different forms of energy" is derived from substituting the definition of the term 'energy' into the term "Different forms of energy" for the word 'energy' then the following result can be attained: Different forms of a quantity that can be assigned to every particle, object, and system of objects as a consequence of the state of that particle, object or system of objects. This shows that the relationship between the concepts 'energy' and 'forms of energy' is not straight forward and the attentive reader is therefore left in doubt of how these two concepts relate to each other. I started the subject 'energy in itself' a bit rough and I would like to reformulate the question, which to my opinion remains unanswered by the energy-page, but this time in a more gentle way:

- Is energy in itself a form of energy like gold in itself (i.e., unformed gold) which also can be seen as a form of money or currency and is in fact a kind of supreme form of money because it used to be in many cases the foundation of a monetary system and nowadays is almost more fundamental than any monetary system, or,

- Is energy in itself only an abstract representative (without any essence like the numbers on a screen) of the collection of forms of energy which determine the state of a quasi enclosed system (i.e., particle, object or system of objects)?

If both formulations are incorrect than I’m very eager to learn how 'energy' and 'form of energy' relate to each other. --Knoxjohnson (talk) 08:16, 7 April 2010 (UTC)

As I understand it, energy does not have a form in and of itself. It is to be understood only in the collection of its various forms, rather like "art" is to be understood only as the collection of various pieces of art. It does no good to say "but I want to see art itself without any particular representation of it." That's not available.

I will admit that Feynman in his lecture goes beyond the idea that there are not natural units or divisions in a homogenous value for energy. I believe he also means to state that energy exists only in a differential form, like potential. So you can talk about differences in two energy states, and say that these differences are conserved, but there's no absolute value to act as a "floor" or constant of integration.

I think I know WHY Feynman would think that way, and that is that energy is frame-dependent, without any obvious frame to choose as the "right" one. It's conserved in any frame, but the absolute value that is conserved in each one, is different!

Personally (and this is a matter of taste) I think the energy represented by the invariant energy or invariant mass of a system is a little more "real" than the other kinds, and nature seems to agree, inasmuch as you can change energy of a particle all you like by changing frames, but if you haven't got enough energy in the COM frame (where energy is minimal) to do the transformation you want to do (make a pair of new particles, say) you can't do it. So nature sort of keeps track. That minimium-energy frame (the COM frame) is then sort of the "preferred" one, at least in that sense. SBHarris 05:00, 15 April 2010 (UTC)

If you want Energy and Action let's look at a lot of Energy and Action, like in the Whirlpool Galaxy. There we see a large manifestation of matter with action and emitting Energy. And the matter is being consolidated by a natural accumulation process that we're still trying to understand. And could the matter be condensed action? I don't know. But I don't think so. I'm like the Grandma described by Dr. Asimov. I think it's turtles (er matter) all the way down into protomatter. And how do we receive information about this action? Well some part of the matter gets to us carrying amounts of energy perceptible to a nerve ending in our sense of sight. And our sense of sight is not involved with looking at a modulated wavefront, but rather with a nerve ending's being able to accumulate enough action (of matter) to result in biological nerve action in our body.WFPM (talk) 06:12, 15 April 2010 (UTC)

So when you start talking about energy without matter, it's like trying to talk about a ghost of somebody who never existed.WFPM (talk) 14:13, 15 April 2010 (UTC)

Error in gravity formula.

The formila in Gravitational energy section should be: E = -G*m1*m2/r^2 92.247.247.23 (talk) 23:00, 16 May 2010 (UTC)