Atomic Fission Mass

[Fax_Monkey]

Please can i ask a quick 2 part question. Im only trying to get my head round this so
please slap me around if i get fundamentals wrong.

When an atom is split some of the mass is converted to energy ( E=MC2).
If we could re-combine the left-over bits of matter and magically reverse the Energy back
into mass - Would we be back to the starting mass of our atom or would there be some mass missing?
In other words do we lose a little bit extra in the whole process? and if we do - what is the cause?


sorry for the daft question but im useless at maths

 

[origin]

Please can i ask a quick 2 part question. Im only trying to get my head round this so
please slap me around if i get fundamentals wrong.

When an atom is split some of the mass is converted to energy ( E=MC2).
If we could re-combine the left-over bits of matter and magically reverse the Energy back
into mass - Would we be back to the starting mass of our atom or would there be some mass missing?
In other words do we lose a little bit extra in the whole process? and if we do - what is the cause?


sorry for the daft question but im useless at maths

Actually that is an excellent question!

As you probably know with a fusion reaction (think hydrogen bomb) a heck of a lot of energy is released. That is because when 2 hydrogen atoms (actually deuterium, a proton and a neutron) are fused into helium the resulting mass of the helium is less than the mass of the 2 deuterium atoms and the left over mass is converted to energy, E=mc^2. Now with heavier atoms typically less energy is released, all the up to nickel. Once you get into atoms that have a mass above nickel it takes energy to combine the parts into the whole.

So, if you were to combine the parts of a fision reaction (the fission products) back together it would take a lot of energy and that energy would be converted to mass, m=E/c^2. It would take the same amount of energy released in the fission reaction to be put back in to the fusion reaction.

That is why uranium is created in supernovas - there is a tremendous amount of energy in the explosion and some of the energy results in collisions of lighter elements into very heavy elements.

Cool stuff Not the bomb parts though :x

 

[Fax_Monkey]

Thanks for the info - that all makes sense. I was just thinking of how the universe tags an atom or particle
to identify it as a mass particle as opposed to non-mass energy etc.

I was wondering if instead of some hidden 'tag' attatched to all matter at creation or some kind of field or particle
in space around matter which labels it as Mass, wouldn't it make more sense if the thing which identifies a masss particle is it's simple 4 dimensional structure - as opposed to energy particles which seem to have dimensional duality to their nature? ( so Einstein and quantum theory can live happily together)

That space itself applies mass to the matter structure without the mass particle being involved at all - so it's instantaneous and differenciates between matter and energy without expending any energy or assigning markers.

This would be seem the simpler solution and would mean that they won't find god particles or gravitons in the atom smashers - but it would mean gravity and attraction of masses would have to be explained as working from the outside - in.

I wish i'd studied physics in school it seems so compelling - and sorry for my lunatic idea!

But i guess it would also mean that there's a whole pile of basic mathematical truths yet to be found



Anyway sorry to ramble