Is Energy Only What We Think It Is?

[afcsimoes]

If time is defined as "the way to order events from past to present to future", then no events implies no time

Please explain. Time is measured by clocks. A clock is something where periodic changes occurs. When there are no changes there are no time? But if I MUST have a clock to measure the time...

 

[Neandethal00]

DaleSpam submitted a new PF Insights post

What is Energy?

Continue reading the Original PF Insights Post.

I do not want to start a new thread, I think this Energy thread is the right place to ask a new question.

Is Potential Energy Real Energy?

In my opinion the answer is NO. A stationary object has no energy.

 

[bhobba]

Is Potential Energy Real Energy? In my opinion the answer is NO. A stationary object has no energy.

That's one reason why the definition I gave based on Noethers theorem IMHO is the best - it avoids all this stuff.

Yes its real energy, just as real as kinetic, or any other kind of energy.

Energy is simply a quantity required because the laws of physics do not change with time, or to be even more exact, required by an inertial frame - but detailing that will take us too far from the purpose of this thread. Start a new thread about the laws of physics and inertial frames if it interests you.

Thanks
Bill

 

[Neandethal00]

That's one reason why the definition I gave based on Noethers theorem IMHO is the best - it avoids all this stuff.

Yes its real energy, just as real as kinetic, or any other kind of energy.

Energy is simply a quantity required because the laws of physics do not change with time, or to be even more exact, required by an inertial frame - but detailing that will take us too far from the purpose of this thread. Start a new thread about the laws of physics and inertial frames if it interests you.

Thanks
Bill

Thanks Bill for all the links you posted above on Noethers Theorem. Isn't it sad so many brilliant minds like Emmy Noethers go unknown in history of science. Even though I have to read them a few more times to understand her theorem, but its conclusion has touched the area from which I made the statement about Potential Energy.
In uncertainty principle I noticed there is a relation between energy and time.

 

[anorlunda]

Please explain. Time is measured by clocks. A clock is something where periodic changes occurs. When there are no changes there are no time? But if I MUST have a clock to measure the time...

Think of causality, cause before effect. Before and after express concepts of time. We only need clocks to measure the quantity if time.

 

[Mark Harder]

If we ignore the different classical classifications of energy (heat energy, sound energy, etc) and take a fundamental view, can we say that all energy at the fundamental level is ultimately one of these four categories:

• Kinetic;
• Static, ie deriving from an object/particle's position in a physical force field;
• Energy incarnated in mass; and
• Dark energy, which we know little about.

IH

Shouldn't we extend that list? There are thermodynamic potentials and associated generalized forces related to generalized gradients of the thermodynamic potentials. Thermodynamic potentials include internal energy, enthalpy, free energy and others.

Of course, thermodynamic energies are a bit more complicated than the mechanical energies that generate mechanical forces, in that they include the mysterious, vaguely defined energy called 'heat'. Heat is not a true potential. Nor is it something that 'flows', an outdated usage left over from the phlogiston theory of heat, which held that the stuff that raised temperatures was this massless invisible fluid that flowed from hot bodies to cool ones. Nor is it a single, differentiated form of energy like the mechanical potentials. In fact, it can be in the form of any of them. Perhaps it's best defined as the sum of all the energies that increase as the temperature of a system is increased. Maybe heat is thermo's equivalent of mechanical kinetic energy, an energy that exchanges one PE for another. Heat an iron bar, for example, and it will radiate light, so the heat given to the bar must have been transmuted into quantum jumps in the electronic energy of the iron atoms, which then is lost as electromagnetic energy in the form of photons.

 

[HomogenousCow]

I feel like calling something a "defined quantity" might make it sound like a useless or ad hoc measure to laymen.

 

[Dale]

Several speculative posts and responses have been deleted and this thread is now closed.