# Energy:The real thing

## Main Question or Discussion Point

What exactly makes forms of energy different from each other?

Can we say that mass is a dense concentration of energy?

## Answers and Replies

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Hey pls sum1 answer this

disregardthat
Energy is in some way the same as mass yes. I believe it 'connects' the elementary point(0-dimensional) particles to eachother, making particles like protons, and neutrons. And it also connects them to eachother making atoms, and molecules.

It has the effect of increasing the mass of the object. Well, I don't know if this is 100% correct, but no one else is answering...

cristo
Staff Emeritus
What exactly makes forms of energy different from each other?
Energy can be defined as the abilty for a force to do work. So, the different forms of energy arise due to the variety of different forces.

Hey ppl i greaatly appreciate ur views.So i gues we CAN say mass is concentration of energy.So now i hav another doubt,Why are forms of energy different?

Different forces?Forces all of em hav the same effects!

ZapperZ
Staff Emeritus
2018 Award
For those of you who think that mass can be defined as nothing more than "concentrated energy", consider the following:

Take an example of "pure" energy such as photons. Now clump them all very tightly to form as mass per the scenerio of the OP. Now explain to me the following:

1. photons have no charge, yet, electron, quarks, etc... all do. Where do these charges come from?

2. Photons have spin of 1. elementary fermions have spins of 1/2. How do you get the basic projection of the "units" of 1 to get spin of 1/2?

3. Photons do not interact via the weak interaction (they don't, at this point, participate in strong interactions either, but in some postulated theory, they might in higher order interactions). Yet, we know many particles that do. Where did that come from?

Zz.

Hi ZapperZ,

see first of all u cannot clump energy in motion(photons CANNNNOT exist at rest).And hence the energy together wont hav spin.So this situation is INVALID SIR!!

and ZapperZ,When mass is "converted" to energy on nuclear reactions(say light energy therefore photons),how does spin change suddenly?????

Also ZZapperZ,light shud create gravity if focussed to such an extent that it may hav a very strong gravitational field.This is as energy has the same effects of mass!

ZapperZ
Staff Emeritus
2018 Award
What exactly makes forms of energy different from each other?

Can we say that mass is a dense concentration of energy?
Hi ZapperZ,

see first of all u cannot clump energy in motion(photons CANNNNOT exist at rest).And hence the energy together wont hav spin.So this situation is INVALID SIR!!
But isn't that what YOU are claiming or asking in your original question? A "photon" is what most would consider as a "pure energy". So? I was merely demonstrating what you are asking for and then I turn around and applied it to see what kind of results one would get.

So it appears that you have answered your own question.

and ZapperZ,When mass is "converted" to energy on nuclear reactions(say light energy therefore photons),how does spin change suddenly?????
This is because the mass just doesn't appear out of nowhere. When a photon is converted into mass via pair production, you have several things that goes on (i) the net charge is conserved because of the production of the particle and its antiparticle partner (ii) the spin is conserved because of the same reason, and (iii) momentum is conserved because such a process can only occur in the vacinity of a more massive particle to take up the missing momentum. The same in a nuclear reaction. There are other particles involved in the process. You just don't see a particle spontaneously dissolve into just pure energy all by itself with nothing else going on.

It isn't as simple as "mass is just a concentration of energy".

Zz.

ZapperZ
Staff Emeritus
2018 Award
Also ZZapperZ,light shud create gravity if focussed to such an extent that it may hav a very strong gravitational field.This is as energy has the same effects of mass!
Show me where this has occured and been observed.

Zz.

and the light q sry
it SHUD occur thats wat im saying.U cannot feel it

cant the nuclear reaction example be due to change of density of energy!IN GR dense energy curves spactime more than energy spread out

Here in the nuclear reaction case,mass is CONVERTED to energy.Im sry as i wrote energy>>mass

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ZapperZ
Staff Emeritus
2018 Award
Here in the nuclear reaction case,mass is CONVERTED to energy.Im sry as i wrote energy>>mass
It doesn't matter. There is STILL a bunch of particles involved. In the matter-antimatter anhilation, you STILL need two particles to maintain the conservation. You just don't have a particle spontaneously disappear into energy with nothing else involved.

Zz.

Hey Zapper ok so HOW exactly does mass get converted into energy.From scratch pls explain

ZapperZ
Staff Emeritus
2018 Award
Hey Zapper ok so HOW exactly does mass get converted into energy.From scratch pls explain
Hell if I know. I'm not the one who wants to make any speculation. Someone else might.

However, all I care about is to make sure someone point out the inconsistency with your original question. When I see a series of responses of people agreeing with that concept, then I see that something hasn't been thought through carefully.

Zz.

PLsss im not trying to contradict u ,but only trying to learn.Please enlighten me.I shall chek in 2morow.Good nght

It doesn't matter. There is STILL a bunch of particles involved. In the matter-antimatter anhilation, you STILL need two particles to maintain the conservation. You just don't have a particle spontaneously disappear into energy with nothing else involved.

Zz.
i'm new
so plz tell me wat do u mean by "PURE" energy like photon

For those of you who think that mass can be defined as nothing more than "concentrated energy", consider the following:

Take an example of "pure" energy such as photons. Now clump them all very tightly to form as mass per the scenerio of the OP. Now explain to me the following:

1. photons have no charge, yet, electron, quarks, etc... all do. Where do these charges come from?

2. Photons have spin of 1. elementary fermions have spins of 1/2. How do you get the basic projection of the "units" of 1 to get spin of 1/2?

3. Photons do not interact via the weak interaction (they don't, at this point, participate in strong interactions either, but in some postulated theory, they might in higher order interactions). Yet, we know many particles that do. Where did that come from?

Zz.
photons hav no charge i agree yet mass formed from it has charged particles.so wats the big deal. same happens wen neutron (uncharged) gives beta emission and protns both of wich r charged. wat i guess(its only a guess) the overall charge is conserved.

What exactly makes forms of energy different from each other?

Can we say that mass is a dense concentration of energy?
well just a guess think its rong. forms of energy r not different from each other.eg thermal energy often referred to as heat is a kind of kinetic energy because it is partly because of the motion of atoms or molecules within a solid, liquid or gas.Similarly, radiation energy, also commonly known as light energy, is often portrayed as being carried by moving photons.

well radiation energy is not exactly due to above reasons since photons have no invariant mass and thus the energy required to accelerate them to their velocity (and thus which is associated with their motion) cannot be calculated using other kinetic equations.

Also ZZapperZ,light shud create gravity if focussed to such an extent that it may hav a very strong gravitational field.This is as energy has the same effects of mass!
i agree ENERGY HAS SAME EFFECTS OF MASS.

one example is photoelectric effect.

photon which is "PURE" energy wen strikes an electron its displaces it. the effect is same as wen an electron is hit by a mass.

so anantchowdhary is rite.

ZapperZ
Staff Emeritus
2018 Award
i agree ENERGY HAS SAME EFFECTS OF MASS.

one example is photoelectric effect.

photon which is "PURE" energy wen strikes an electron its displaces it. the effect is same as wen an electron is hit by a mass.

so anantchowdhary is rite.
The photon is NOT converted into an electron in there, thankyouverymuch. The electron is already present in the conduction band! All that happens is that the part of the photon energy is transfered into the electron's kinetic energy. There is NO energy-mass conversion there. The "similarity" of the scattering via a "mass" is only superficial. A scattering via another mass is NOT called the photoelectric effect. The energy and momentum dependence of the emitted electron are different!

I'd suggest you re-examine your understanding of the photoelectric effect, AND, do a bit of a search on here first regarding what has been said on PF.

Since you are new, just so you know a bit more of the situation and know what you're dealing with, the "avatar" or picture you see on your left under my member name is a snapshot of a photoemission spectrum that *I* took when I did my postdoc. This is not meant to impress you, but rather to indicate that in terms of the physics and experimental aspect of the photoelectric and photoemission phenomena, I might know "a bit more" than the average person on the street.

Zz.

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