Question about nuclear reactions

[zanzibar]

So... the number of protons and neutrons before and after uranium decays, is it the same?

[Quin]

So... the number of protons and neutrons before and after uranium decays, is it the same?

Yes
(I don't believe there is any beta decay, but I could be wrong)

[Xordan]

An interesting piece of info that I came across in a recently published paper (no link sorry) is that something like 70% of the mass of a proton (I think) is actually the kinetic energy of its constituent quarks.

[Bamko]

yes, that is called the conservation of nucleon number.  of course they are not all attached to the decay daughters, some are "running around" but they are neither created or destroyed.

BTW, I googled your last question, a decent explanation: http://physics.bu.edu/py106/notes/RadioactiveDecay.html note the discussion on mass defect.  it exists and is measurable, but is a relatively small amount.  check out the link, i think that answers your question without me personally releasing any classified information.

it is a lot like spoilers on this forum, I can link to information I know, even when i can not reveal it myself.  For example i can not tell you much about my ship, even though it has since been decommisioned, but Jane's Fighting ships has a lot of information that would send a classified person into the brig, if they were to release it themselves.

[Quin]

beta decay started to bug me so I looked it up.

From wikipedia-

Since the nuclei that can readily undergo fission are particularly neutron-rich (e.g. 61% of the nucleons in uranium-235 are neutrons), the initial fission products are almost always more neutron-rich than stable nuclei of the same mass as the fission product (e.g. stable ruthenium-100 is 56% neutrons, stable xenon-134 is 60%). The initial fission products therefore may be unstable and typically undergo beta decay towards stable nuclei, converting a neutron to a proton with each beta emission. (Fission products do not emit alpha particles.)

- so I was kind of right
The fission products have the same number of total neutrons and the same number of total protons, but the fission products may undergo beta decay converting neutrons to protons.  But as Bamko pointed out the total number of nucleons (neutrons + protons) will always remain the same

[Prolix]

I think it would depend on the relative strength and duration of the reaction. I can imagine a reaction of such power that at least some of the atomic constituents were broken up into their quantum components. These quantum particles might well recoalesce or recombine into atomic particles quite quickly but that would just be deceptive to the casual observer.

[Bamko]

can not see it, so it must occur.... 


i really think this is being over-thought.  Almost all the energy comes from the kinetic energy of the fission products in the fission and/or alpha decay of uranium.

we can wax poeticaly about mass loss in any reaction, chemical or nuclear, but that is "over-nukeing it" And this is from a former "nuke" so I know what that looks like. 

Most do not consider the effect of mass "creation" by sunlight in a plant, because it does not create any new protrons or neutrons, and the mass gain is so insignificant compared to the amount of carbon gain by respiration.

Where does energy come from in a nuclear reaction? From the kinetic energy of the products, mostly. 

But can we spin out wheels and make this into "the philosophy of matter"?  sure we can.  We already have.

but then, how do you know matter even exists? 

[Xordan]

Most do not consider the effect of mass "creation" by sunlight in a plant, because it does not create any new protrons or neutrons, and the mass gain is so insignificant compared to the amount of carbon gain by respiration.

Urr, there is no mass 'creation' in light photosynthesis. The light is used to split an electron from chlorophyll (which it regains later from water), so there's no energy to mass done here.

Also, the mass 'loss' in a nuclear reaction is a fundamental component to the process, the discovery of it was quite major in the field. So I don't know what you're talking about when you say it's poetic waxing.

[Quin]

Almost all the energy comes from the kinetic energy of the fission products in the fission and/or alpha decay of uranium.
...
Where does energy come from in a nuclear reaction? From the kinetic energy of the products, mostly. 

The added kinetic energy of the fission products is the energy of the missing mass.

[zanzibar]

I think it would depend on the relative strength and duration of the reaction. I can imagine a reaction of such power that at least some of the atomic constituents were broken up into their quantum components. These quantum particles might well recoalesce or recombine into atomic particles quite quickly but that would just be deceptive to the casual observer.

Is this just what you think, or are you citing something?

[Prolix]

What I think of course but if you consider what might happen in the collapse of a supergiant star the forces are so great that the streams that shoot out from the event horizon are likely enough to break up the atomic particles. Now once you get into quantum particles it gets a lot more dicey and my understanding is far more limited. I am a lay person and not a scientist of any type. Certainly what happens within a singularity is a subject of much debate. From what I understand, large stars that go nova become neutron stars, huge ones become singularities where even the neutrons break down.

At the quantum levels I think some of the particles are considered massy while others not so much.

Nobody knows what really happens.
Anyway my imagining does not necessarily match reality

[zanzibar]

What I think of course but if you consider what might happen in the collapse of a supergiant star the forces are so great that the streams that shoot out from the event horizon are likely enough to break up the atomic particles. Now once you get into quantum particles it gets a lot more dicey and my understanding is far more limited. I am a lay person and not a scientist of any type. Certainly what happens within a singularity is a subject of much debate. From what I understand, large stars that go nova become neutron stars, huge ones become singularities where even the neutrons break down.

At the quantum levels I think some of the particles are considered massy while others not so much.

Nobody knows what really happens.

My question was whether or not you were citing from something you've read, or if it was just your speculation.

Anyway my imagining does not necessarily match reality

Exactly.

[Prolix]

Well to be more specific I was relating my poor understanding of vaguely remembered reading of various articles in popular science magazines. Particularly Scientific American which I buy maybe once a year or so. I think the last edition I bought talked about this stuff, I do know it talked about multiple universes as well. Certainly not everything you see in such a magazine is definitive and sometimes turns out to be complete speculation.

[zanzibar]

Well to be more specific I was relating my poor understanding of vaguely remembered reading of various articles in popular science magazines. Particularly Scientific American which I buy maybe once a year or so. I think the last edition I bought talked about this stuff, I do know it talked about multiple universes as well. Certainly not everything you see in such a magazine is definitive and sometimes turns out to be complete speculation.

Ah.  If you happen to find the article you were pulling ideas from, I'd read it.

[Prolix]

Well this months (feb09) Discover magazine has an article "The Violent Birth of Stars" and another "Quantum Secrets of Life",  This months Scientific American has "Naked Singularities"  The older magazines appear to have been recycled but you ought to be able to find them in your local library. You might try a search of Scientific American's website. Discover magazine has a website too

I'm sure most of the other science magazines have stuff online as well but the hard copies probably have more stuff in them.