# I Does energy take up space?

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1. Mar 14, 2016

### Pjpic

Does energy take up space? In other words; if one particle has more energy than another, does the more energetic particle have to be larger in size?

2. Mar 14, 2016

### hackhard

mass is a form of potential energy so energy sometimes takes up space.
but
is never true even if one particle has more mass than another, heavier particle can by much smaller in size

3. Mar 14, 2016

### Isaac0427

It depends on what type of energy you are talking about. You can have:
-Kinetic energy (E=.5*mv2)
-Potential energy (E=mkx)
-Mass energy (E=mc2)
-Momentum energy (E=pc)
-Heat energy (there is no exact equation that I know of, but it can be defined as the average kinetic energy of many particles)
Each of those (except for potential energy), UNDER CERTAIN CONDITIONS can make something larger, and under other conditions, they do not.

4. Mar 14, 2016

### Isaac0427

I'm pretty sure it is its own type of energy (I generally call it combined with momentum energy "relativistic energy", as the energy is described in relativity however I don't know if that is an accepted name).
It is not never true, it is just not always true, or sometimes true.

5. Mar 14, 2016

### brainpushups

No. Energy is an abstract physical concept and can only be measured or calculated indirectly.

Mass is not size/volume. Having more mass does not mean the object takes up more space. Also, this is under the 'classical' forum so I think we can safely ignore relativistic characterizations of energy.

6. Mar 14, 2016

### hackhard

it can never be said that a particle has more total energy than another since total energy of body in not measurable
but loss in total energy is theoritically measurable and we can say a body has lost more energy than other

7. Mar 15, 2016

### Staff: Mentor

Why do you think this might be the case?

8. Mar 15, 2016

### Pjpic

Things take up space. If energy (if that is a thing) is added to an electron; it would seem that the electron would either have to get bigger or that there was empty space inside of the electron where the additional energy could fit. On the other hand, if electrons are dimensionless points; maybe my question isn't valid.

9. Mar 15, 2016

### Staff: Mentor

Energy isn't a "thing" in itself. It's a property of a "thing," or system. You can't isolate "pure energy", just as you can't isolate "pure color".

10. Mar 15, 2016

### Pjpic

So energy is one property of a force carrying particle?

11. Mar 15, 2016

### NathanaelNolk

Not necessarily a force carrying particle, it can be a property of a system for instance.

12. Mar 15, 2016

### nasu

"force carrying particle" does not make sense.
Force is a measure of interaction between particles, not something that a particle will "carry". It is not a property of a particle or of any other object..

13. Mar 15, 2016

### David Lewis

I suppose an electron carries an electric force field with it, and every particle of mass carries with it a gravitational field, in a manner of speaking.

Einstein implied that space and time are intertwined and, although we can't say energy takes up space, we can say that energy and time are complementary physical properties.

Last edited: Mar 15, 2016
14. Mar 15, 2016

### Khashishi

"take up space" is not something that is clearly defined in physics.

15. Mar 15, 2016

### Isaac0427

I find the concept of volume to be perfectly defined in physics.

16. Mar 15, 2016

### DaveC426913

Photons - light and other forms of electromagnetic radiation - do not normally interact. They can pass right through each other. You cannot fill a box "full" with light. In that sense, energy does not take up space.

Matter, on the other hand, obeys the Pauli Exclusion Principle. It does take up space, and you can fill a box full with it.

17. Mar 15, 2016

### 256bits

That is a representation of a hydrogen atom in its ground state, and in two different exited states.
Seems bigger when exited.

Energy level at ground state Eo= -13.6eV
Energy level at first exited state = -3-4eV
At infinity, E = 0 eV

It seems as energy is added to the electron-protron system, it does get bigger.

18. Mar 16, 2016

### Drakkith

Staff Emeritus
Sure, because the addition of energy excites the electron to an orbital with a larger average radius. But it is the electron that takes up space, not the energy itself.

19. Mar 16, 2016

### 256bits

Object, or particle, in question is the electron-proton composite, not just the electron nor the proton each individually. And this composite has the gain in potential energy when the atom is excited. The excited atom as a particle takes up extra space.

20. Mar 16, 2016

### Drakkith

Staff Emeritus
Yes it does. So what?