# Does it take work to hold an atom together?

1. Apr 18, 2006

### Lucretius

I was wondering if it took any physical work to hold an atom together. The reason I am asking is because someone had asked about the proposed Heat Death of the universe. My thought was that only elementary particles and radiation would exist because everything else would have broken up. The other person stated that atoms would still exist because it does not take work to hold them together. Is this true?

2. Apr 18, 2006

### Gokul43201

Staff Emeritus
No work is done in holding a stable atom together. Recall how work is defined.

3. Apr 19, 2006

### Lucretius

W=Fd, but because there is no d, there is no work?

4. Apr 19, 2006

### Mk

Yes. That is correct.

5. Apr 20, 2006

### Modey3

Hello,

I'm not sure that "d" is constant. The strongforce and electromagnetic force work against each other. Since the strongforce is caused by gluon exchange between protons the force-time response should look like a delta function. And if the electromagnetic interaction between the particles is continuous with time I would expect dynamic behavior for the protons. This implies that work is being done to hold the protons together. However, I'm not a particle physics person so don't take my explanation as gospel.

Best Regards

Modey3

6. Apr 20, 2006

### Etki

i tihnk there is no d...so w=fd there is no work

7. Apr 20, 2006

### ZapperZ

Staff Emeritus
Be very careful here. First of all, gluons just doesn't hold "protons" together. Rather it is binding agent between all "hardrons", i.e. anything with quarks. This includes protons, neutrons, mesons, etc.

Secondly, "holds atom together" can mean way too many things. If it means making sure the electrons don't fly apart, then this can be as simple as electromagnetic intereaction (no strong force here), or as complicated as the inclusion of electroweak component.

As with many other questions here, until the OP produces a clearly explanation of the question, things are left in a fuzzy state.

Zz.

8. Apr 20, 2006

### Lucretius

By doing work, I meant I thought it took work to hold two protons together in the atomic nucleus. Two like charges should repel, so at first I thought work was being done to hold them together and to negate the electromagnetic force which should cause the two protons to push apart.

9. Apr 20, 2006

### ZapperZ

Staff Emeritus
But the term "Work" has a clear definition. You do work when the force you apply causes a displacement. Now by simply knowing that the nucleus isn't moving on average (do you see your coffee cup moving when you apply no force to it?), you can immediately deduce the obvious.

Applied force doesn't imply work done. Only applied force that resulted in a net displacement in the direction of that force results in a work done. This is what is defined by "work".

To complete the explanation, you need to look up the "strong force", which is the force between nucleons that is the "glue".

Zz.