What is Energy? - Physics Forum Introduction

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In summary: Energy is a property of objects and systems of objects. There are various forms of energy (e.g. mechanical, thermodynamic, informational), and they can interconvert from one form to another. Energy is also conserved in a closed system.
  • #1
basePARTICLE
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As an introduction to this physics forum, let me begin by asking:

What is energy?

Is Energy something tangible or is Energy only apparent when certain base characteristics belonging to the topological composition of our universe interact or you may have another idea in mind which can play out in the real world?


Yes welcome to our universe :smile:
 
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  • #2
Your post is mostly word salad. You're using words like "topology" incorrectly, for example.

Energy is just a number we assign to a system to quantify its ability to perform work. No more, no less.

- Warren
 
  • #3
chroot said:
No more, no less.
Sometime, the energy is MORE than ability to perform work. For example, if thermal energy is Q, the ability to perform work is only Q*(T2 -T1)/T2
 
  • #4
wordsalad or not, the ability to perform work is a simplified explanation to an observation that we make on a regular basis. doing things like increasing the mass of an object containing kenetic energy. manufacturing matter from apperantly nothing... bending the fabric of space...

the question I often ponder is how does the energy given to a base ball in the form of kenetic energy be a direct realitive to the material of the baseball.

of course my cheese may have slipped off my cracker with this post!
 
  • #5
Energy is DEFINED as "the ability to do work".

The ability to do work is in turn determined by the current state of the system in question. Gravitational PE depends on the distance from a mass (or masses). KE depends on velocity, etc.

There is nothing in our current model that suggests energy consists of some "stuff" which seems to be an idea that persists in this thread.

Claude.
 
  • #6
"topological composition of our universe interact"?? I've taken topology and I can't make heads or tales out of that. I can't even determine whether "interact" here is supposed to be a verb or a noun. I would think of "interact" as a verb, but that doesn't make grammatical sense here.

Basically, "energy" is a bookkeeping device. In basic kinematics, with simple "perfectly elastic" collisions, it was recognised that a particular combination of variables, (1/3)mv2, "kinetic energy", remained the same and so "conservation of energy" became a good rule for solving such problems. Add changes in height and you had to add "potential energy" to "balance" the equations. Add motion with or against a non-conservative force and you had to add "work". Put in friction and you had to add heat as a type of "energy". The history of mechanics has been one of creating new kinds of "energy" in order to keep "conservation of energy" true.
 
  • #7
HallsofIvy said:
"topological composition of our universe interact"?? I've taken topology and I can't make heads or tales out of that.

that's because your last name isn't Bogdanov or Bogdanoff and you do not host a French pop-physics (or pseudo-physics) television show. if you were thus qualified, Halls, you would know what that means. :rolleyes:
 
  • #8
To be fair, the OP did ask a question central to physics.

Energy is a property of objects and systems of objects. There are various forms of energy (e.g. mechanical, thermodynamic, informational), and they can interconvert from one form to another. We know some properties of energy- the total amount is conserved in a closed system, we can interconvert one form of energy to another in controlled experimental conditions, and we can quantify how much energy a particular object/system has.

As for what energy 'is', you could just as easily as "What is 'red'? The fact that a simple answer doesn;t exist does not make the concept any less useful.
 
  • #9
HallsofIvy said:
Basically, "energy" is a bookkeeping device.
...
The history of mechanics has been one of creating new kinds of "energy" in order to keep "conservation of energy" true.
Yes, absolutely!

Actually, we have several such bookkeeping devices, like momentum, angular momentum, mass (in nonrelativistic case) etc.

Actually, I am not sure that number of such devices is finite. Because some nonlinear equations have INFINITE number of independent integrals of motion. The first three of them are usually associated with mass, momentum and energy of the system. The rest of them are terra incognito.
 
  • #10
HallsofIvy said:
I've taken topology and I can't make heads or tales out of that. I can't even determine whether "interact" here is supposed to be a verb or a noun. I would think of "interact" as a verb, but that doesn't make grammatical sense here.

Mmm, I thought that it did make grammatical (if not semantical) sense, and is, as such, a qualified, syntactically correct Bogdanov statement.

"Is Energy something tangible or is Energy only apparent when certain base characteristics belonging to the topological composition of our universe interact or you may have another idea in mind which can play out in the real world?"

is, as far as I understand, a question phrase composed of 3 sub-statements on the same level:
"Is Energy something tangible"

OR

"is Energy only apparent when certain base characteristics belonging to the topological composition of our universe interact"

OR

"you may have another idea in mind which can play out in the real world?"

although what is strange is that the last statement is an intonation question, while the other two are questions with inversion.

Let's look at:

"is Energy only apparent when certain base characteristics belonging to the topological composition of our universe interact"

which is, I would think, a correctly formulated Bogdanov phrase.

It has a main clause:
"is energy only apparent"

and a sub-clause (of time, or of condition, with "when"):
"when certain base characteristics belonging to the topological composition of our universe interact"

subject: "certain base characteristics, belonging to..."

verb: "interact"

It are hence the characteristics that have to interact.
Which characteristics ?
Those belonging to the topological composition of our universe.

It is at the time, or on the condition of those characteristics interacting, that energy is apparent, and only then.


:smile:
 
  • #11
Can mental energy be considered here? chemical, and electrical, reactions in the head can sometime be extreme to the point of feeling exausted, both mental and physical.
I sometimes get a flood of thoughts that continue for days, every waking hour, and then i seem to sort of shut down, i'll spend time doing things that seem to require very little thought or attention. This cycle repeats on a somewhat regular basis.
 
  • #12
RonL said:
Can mental energy be considered here? chemical, and electrical, reactions in the head can sometime be extreme to the point of feeling exausted, both mental and physical.
I sometimes get a flood of thoughts that continue for days, every waking hour, and then i seem to sort of shut down, i'll spend time doing things that seem to require very little thought or attention. This cycle repeats on a somewhat regular basis.

This is not an issue in "mechanics", and so it is not relevant here.

Zz.
 
  • #13
chroot said:
Your post is mostly word salad. You're using words like "topology" incorrectly, for example.

Energy is just a number we assign to a system to quantify its ability to perform work. No more, no less.

- Warren
I disagree with your assessment on my usage of the word topology. Mathematically the standard model, can be incorporated into a topology that can describe simple things like atoms. This is apparent because when protons, neutrons and electrons are combined, the elements that emerge are recognized for what they are, due to the combinatorial process, which is well known. Therefore to say that our universe can be described by a topology, even if it is complex in nature is closer to the truth, than you have been willing to admit.
 
  • #14
chroot said:
Your post is mostly word salad. You're using words like "topology" incorrectly, for example.

Energy is just a number we assign to a system to quantify its ability to perform work. No more, no less.

- Warren
The fact that Energy in significant units does quantify an ability to do work, does not in any way, negate the quest for knowledge concerning what is it that causes this ability to perform work to be manifest. Mere numbers will not cut the cloth so to speak. Perhaps you will move towards the definitive technical term - force!

On another note, although I accept the definition that energy is no more, no less, an ability to perform work and can subsequently be summarized by a mere number, I submit my hesitation in regarding this as an epistemological coup d'etat.
 
  • #15
basePARTICLE said:
I disagree with your assessment on my usage of the word topology. Mathematically the standard model, can be incorporated into a topology that can describe simple things like atoms. This is apparent because when protons, neutrons and electrons are combined, the elements that emerge are recognized for what they are, due to the combinatorial process, which is well known. Therefore to say that our universe can be described by a topology, even if it is complex in nature is closer to the truth, than you have been willing to admit.
There might well be some validity to what you're trying to say, but I think the problem is that you're using words in a way that raises some suspicion that you might have a less than complete understanding of them.

I've never heard anyone who does research in this area say "the standard model can be incorporated into a topology", much less "the universe can be described by a topology."

Spacetime, Lie Groups - yes. The SM or the entire universe - sounds iffy to me.
 
  • #16
Claude Bile said:
Energy is DEFINED as "the ability to do work".

The ability to do work is in turn determined by the current state of the system in question. Gravitational PE depends on the distance from a mass (or masses). KE depends on velocity, etc.

There is nothing in our current model that suggests energy consists of some "stuff" which seems to be an idea that persists in this thread.

Claude.
This is precisely what I am after, your suggestion that the current understanding of energy is less than precise, in light of the new Quantum Mechanics.

This definition of Energy as an ability to perform work can be dated back to Newton, if I am not mistaken, and it seems as if the current trend to walk the physics line without real epistemological support needs its proper attention.

Additionally, I have not claimed as yet anything, that suggests energy consists of some "stuff" as you so eloquently stated it. I have asked for current mental notions which support the nature of Energy, while I have stated my own notion about how I believe energy shows up in our universe. It was stated clearly, but I repeat for effect, apparent when certain base characteristics (belonging to the topological composition) of our universe interact. Some of those base characteristics are summerized by the standard model, including spin and charge.
 
  • #17
basePARTICLE said:
The fact that Energy in significant units does quantify an ability to do work, does not in any way, negate the quest for knowledge concerning what is it that causes this ability to perform work to be manifest. Mere numbers will not cut the cloth so to speak. Perhaps you will move towards the definitive technical term - force!

On another note, although I accept the definition that energy is no more, no less, an ability to perform work and can subsequently be summarized by a mere number, I submit my hesitation in regarding this as an epistemological coup d'etat.
How's this, then: "Energy is that quantity that is conserved as a result of the invariance of Physics under time translation."? (see Noether's Theorem) :smile:
 
  • #18
basePARTICLE said:
This is precisely what I am after, your suggestion that the current understanding of energy is less than precise, in light of the new Quantum Mechanics.

This definition of Energy as an ability to perform work can be dated back to Newton, if I am not mistaken, and it seems as if the current trend to walk the physics line without real epistemological support needs its proper attention.
We can predict measurements of energy, and our measurements agree well with those predictions. What deeper epistemological support is needed in Physics?

I think the earlier post about defining "red" is quite apt. We could go around in epistemological circles for a long time, trying to decide on how we know what "red" really is, but at the end of the day, I don't think we'll be any more able to find the red car in the parking lot.
 
  • #19
HallsofIvy said:
"topological composition of our universe interact"?? I've taken topology and I can't make heads or tales out of that. I can't even determine whether "interact" here is supposed to be a verb or a noun. I would think of "interact" as a verb, but that doesn't make grammatical sense here.

Basically, "energy" is a bookkeeping device. In basic kinematics, with simple "perfectly elastic" collisions, it was recognised that a particular combination of variables, (1/3)mv2, "kinetic energy", remained the same and so "conservation of energy" became a good rule for solving such problems. Add changes in height and you had to add "potential energy" to "balance" the equations. Add motion with or against a non-conservative force and you had to add "work". Put in friction and you had to add heat as a type of "energy". The history of mechanics has been one of creating new kinds of "energy" in order to keep "conservation of energy" true.
Nice thing that mechanics!

One topological basis of our world would consist of things like spin, electric charge, heat, and gravitational states, while another more basic one, would have quark compositions.

How does these interact with each other making it look as if energy exists! or even as things-in-themselves? Do you think that a black hole is a thing-in-itself?
 
  • #20
vanesch said:
Mmm, ...

It is at the time, or on the condition of those characteristics interacting, that energy is apparent, and only then.

:smile:
Hmm, to summarize, interesting thought that one, if not a downright fascinating notion! :smile: :smile:

p.s. could this be symmetry breaking?
 
  • #21
belliott4488 said:
There might well be some validity to what you're trying to say, but I think the problem is that you're using words in a way that raises some suspicion that you might have a less than complete understanding of them.

I've never heard anyone who does research in this area say "the standard model can be incorporated into a topology", much less "the universe can be described by a topology."

Spacetime, Lie Groups - yes. The SM or the entire universe - sounds iffy to me.
That could probably be true, for some unknown reason or the other. The problem may be that I may be using some ungodly anti-symmetric trick, seeing those states are the only ones now available for processing.:smile:

But I will try harder to make myself understood, seeing I will try to stick around here until 2009. good luck?
 
  • #22
belliott4488 said:
How's this, then: "Energy is that quantity that is conserved as a result of the invariance of Physics under time translation."? (see Noether's Theorem) :smile:
When the goal posts are moved, the same effect is realized, isn't it? But one would think that SR shows time dilation to have an effect on energy once mass increases, so is there a contradiction?
 
  • #23
belliott4488 said:
We can predict measurements of energy, and our measurements agree well with those predictions. What deeper epistemological support is needed in Physics?

I think the earlier post about defining "red" is quite apt. We could go around in epistemological circles for a long time, trying to decide on how we know what "red" really is, but at the end of the day, I don't think we'll be any more able to find the red car in the parking lot.
Surely you jest - with a hand held device one could find a red pen under scrutiny.
 
  • #24
I'm being generous when I say this thread is teetering on the boundary of acceptability here. Please keep it about mainstream science, or it will be locked.

- Warren
 
  • #25
chroot said:
I'm being generous when I say this thread is teetering on the boundary of acceptability here. Please keep it about mainstream science, or it will be locked.

- Warren
I think you're being too generous ...
 
  • #26
energy is the ability to do work.

you can feel and contain energy(fat cells etc.).

there are many ways one may decide to look at our universe, decomposing into bases of their choice. if anything has mass, moves or vibrates there is energy.
 
  • #27
energy, force , work they are all the product of same basic philosophy from which emerged the things what we call axioms in maths.

all can be related to the same general idea of philosophy
" nothing happens without a cause", which if not considered , makes science nothing less than a superstition

philosophers observed that things can be moved , and nature tends to change

they called the cause "force"
thus came Newtons laws

to find the change in the nature , they assumed the nature to oppose the change (force field) and then found the most apparent definition of change "work"

now the question arises what causes this change , they come out with "energy", according to basic philosophy.

the law of conservation is very apparent from the basic principle of philosophy
what is the cause of cause?

its again a cause,

thus the net cause must be constant ,(imagining Earth you can move on and on ,thus think that Earth is infinite, but other idea says that Earth is finite and your motion is looped,thus it is same with cause , it is finite but just interacting)I am sorry to deviate from the topic , as to talk of philosophy, but the topic was as basic , as philosophy, as you all know that physics is just philosophy in olden times:smile:
 
  • #28
basePARTICLE said:
Hmm, to summarize, interesting thought that one, if not a downright fascinating notion! :smile: :smile:

p.s. could this be symmetry breaking?

No, it was english grammar...
 
  • #29
vanesch said:
No, it was english grammar...
I don't quite understand, what you are getting at. I thought you made a choice on the subject, not a correction. Am I wrong?
 
  • #30
basePARTICLE said:
I don't quite understand, what you are getting at. I thought you made a choice on the subject, not a correction. Am I wrong?

I analysed the grammar of your convoluted question to show that it was syntactically correct, and to try to know what was the subject, and the verb.
 
  • #31
vanesch said:
I analysed the grammar of your convoluted question to show that it was syntactically correct, and to try to know what was the subject, and the verb.
I thought that is usually done away from forum listings, and as a matter of fact, because you proceeded not to show real content, you have contributed in placing this thread close to limbo - are you sorry?

As for convolutions, that form corersponds to a neat tautology, but this is not the place for these types of interactions, as our esteemed moderator has noted. Can you place at least a bit of content, when replying?

Mine follows.

We all know the famous equation E [tex]\Mc^2[/tex] (M times, c squared).
From this equation it is claimed that Mass and Energy are interchangeable. Do you envisage any problem with this statement in the light (colloquial) that Energy is predefined as the ability to do work and Mass is something tangible (touchable by sensory apparatus). As a further reference to this, when we examine various kinds of work being done as described by physics, none of them are tangible except growth! Can you respond?
 
Last edited:
  • #32
belliott4488 said:
We can predict measurements of energy, and our measurements agree well with those predictions. What deeper epistemological support is needed in Physics?
I think the earlier post about defining "red" is quite apt. We could go around in epistemological circles for a long time, trying to decide on how we know what "red" really is, but at the end of the day, I don't think we'll be any more able to find the red car in the parking lot.
On the two points here of which one relates to the topic while the other veers off course, I will respond to the first and try again with the second.

On the first point, physicists know that, deeper epistemological support, causes further logical consequence. Look at what QM did to our Newtonian world! Gaining consenus and trying to find deeper epistemological support, I think has been the physicist's own game, since, I forgot who it was jumped out of a tub. I know I am justified in looking at Energy with a finer grained postulate in mind!

On the second point made, of locating red, redness, or some convolution of red, I think lies on the basis of a real analysis and perhaps the ability to produce photonically, a darker red. This ability does not materially exist and you actually reflect this view.
 
  • #33
Claude Bile said:
Energy is DEFINED as "the ability to do work".

The ability to do work is in turn determined by the current state of the system in question. Gravitational PE depends on the distance from a mass (or masses). KE depends on velocity, etc.

There is nothing in our current model that suggests energy consists of some "stuff" which seems to be an idea that persists in this thread.

Claude.
It has been previously stated that mass was some sort of bookeeping device for energy, along with momentum. angular momentum, and I would add, the magnetic, electric, and gravitational fields. My point is there is one sore thumb sticking out, that directly references your seeming abhorence, that suggests energy consists of some "stuff".

That sore thum is Mass. Can you address this deviation from the norm, which is field and potential? Try thinking of KE (kinetic energy) as a potential which can be immediately actualized (a one step potential) whereas PE (potential energy) is two steps away from doing real work.
 
  • #34
lilrex said:
wordsalad or not, the ability to perform work is a simplified explanation to an observation that we make on a regular basis. doing things like increasing the mass of an object containing kenetic energy. manufacturing matter from apperantly nothing... bending the fabric of space...

the question I often ponder is how does the energy given to a base ball in the form of kenetic energy be a direct realitive to the material of the baseball.

of course my cheese may have slipped off my cracker with this post!
I could say quite a lot of sensible things about word salads, but I prefer to ask the question about how do you believe dark energy, reflects an ability to do work?

I think part of the answer to your question is its coefficient of restitution. Momemtum is given as m1 = coe * m2 where coe has a value between 0 and 1. The logical consequence of this is something with a small coefficient will not move at all. But that has to do with hitting the base ball. When it is thrown its material has no impact on its initial velocity, then its coefficient of friction in relation to the medium through which it subsequently travels, comes into play, slowing its motion, hardly ever speeding it up.
 
  • #35
I think that the right experimental approach is to probe the higher spacetime dimensions with extremely high energy particle accelerators, say orders of magnitude greater than LHC 2008, so when black holes can be created without resort to the Planck condition, then it is possible to determine the topological background of energy interactions.

I think that the right mathematical approach is the rigorous extension of catastrophe theory, say to devise further specializations and so to push back the boundary of the generalizations.

(in my opinion, it is a very great pity that the Bogdanovs did not follow Thom's approach to structural stability)

(in my opinion, Tony Smith is already on the right theoretical track)
 
<h2>1. What is energy?</h2><p>Energy is a fundamental concept in physics that refers to the ability of a system to do work. It is a scalar quantity, meaning it has magnitude but no direction. In simpler terms, energy is what allows things to happen and change in the universe.</p><h2>2. How is energy measured?</h2><p>Energy is measured in joules (J) in the International System of Units (SI). Other common units of energy include calories (cal) and kilowatt-hours (kWh). In certain contexts, other units such as electron volts (eV) or foot-pounds (ft-lb) may also be used.</p><h2>3. What are the different forms of energy?</h2><p>There are many different types of energy, but they can be broadly categorized into two main forms: potential energy and kinetic energy. Potential energy is stored energy that an object has due to its position or condition, while kinetic energy is the energy an object possesses due to its motion.</p><h2>4. How is energy transferred or converted?</h2><p>Energy can be transferred from one form to another or converted from one type to another. For example, when a ball is thrown, the potential energy in the person's arm is converted into kinetic energy as the ball moves through the air. Energy can also be transferred from one object to another through processes such as heat transfer or electromagnetic radiation.</p><h2>5. What is the relationship between energy and mass?</h2><p>In physics, energy and mass are considered to be two forms of the same underlying entity, known as mass-energy. This is described by Einstein's famous equation, E=mc², where E represents energy, m represents mass, and c represents the speed of light. This means that mass can be converted into energy and vice versa.</p>

1. What is energy?

Energy is a fundamental concept in physics that refers to the ability of a system to do work. It is a scalar quantity, meaning it has magnitude but no direction. In simpler terms, energy is what allows things to happen and change in the universe.

2. How is energy measured?

Energy is measured in joules (J) in the International System of Units (SI). Other common units of energy include calories (cal) and kilowatt-hours (kWh). In certain contexts, other units such as electron volts (eV) or foot-pounds (ft-lb) may also be used.

3. What are the different forms of energy?

There are many different types of energy, but they can be broadly categorized into two main forms: potential energy and kinetic energy. Potential energy is stored energy that an object has due to its position or condition, while kinetic energy is the energy an object possesses due to its motion.

4. How is energy transferred or converted?

Energy can be transferred from one form to another or converted from one type to another. For example, when a ball is thrown, the potential energy in the person's arm is converted into kinetic energy as the ball moves through the air. Energy can also be transferred from one object to another through processes such as heat transfer or electromagnetic radiation.

5. What is the relationship between energy and mass?

In physics, energy and mass are considered to be two forms of the same underlying entity, known as mass-energy. This is described by Einstein's famous equation, E=mc², where E represents energy, m represents mass, and c represents the speed of light. This means that mass can be converted into energy and vice versa.

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