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Just a quick question: why is E = mc^2 always invoked when discussing nukes? |
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Last edited by Xei; 08-02-2010 at 05:23 AM.
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'The petals dance through the wind,
The crimson blood shimmers on the snow,
The shattered heart weeps of hidden sorrow.
And over a pure white sky,
rises a black moon.'
- Max
Does this help? |
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I was merely stating that Newtonian physics isn't sufficient to be of much use in precise, and advanced nuclear operations. E = mc^2 is not essential for nuclear reactions where the main objective is to harness the enery inside the nucleus. And even in that case, I don't see how you could NOT use E = mc^2 to calculate how much kilograms of nuclear fuel are needed, how much energy will be released, etc. etc. In particle accelerators and collision chambers, however, E = mc^2 becomes absolutely necessary. I don't need to explain that. |
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'The petals dance through the wind,
The crimson blood shimmers on the snow,
The shattered heart weeps of hidden sorrow.
And over a pure white sky,
rises a black moon.'
- Max
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the whole point of fission is that a heavy nucleus fissions into two smaller nuclei and converts some of its mass to energy in the process. E = mc^2 is what makes this possible. |
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Last edited by PhilosopherStoned; 08-03-2010 at 01:17 PM.
Previously PhilosopherStoned
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Sorry but I think you're having a fundamental misunderstanding that's leading you to ask an illformed question. |
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Previously PhilosopherStoned
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Last edited by Xei; 08-03-2010 at 03:37 PM.
'The petals dance through the wind,
The crimson blood shimmers on the snow,
The shattered heart weeps of hidden sorrow.
And over a pure white sky,
rises a black moon.'
- Max
Both nuclear and chemical reactions end up with something called mass defect. This mass defect is (or should be, don't remember) the equivalent of the energy released if you use E=mc^2. Now, mass defect is a couple of orders of magnitude larger for nuclear reactions. For chemical reactions it's so small that it's safe to ignore it, but it still exists. |
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SnakeCharmer gave you a good answer, sorry for the misunderstanding. It's what I get for trying to think about this stuff too late at night. |
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Previously PhilosopherStoned
Yes I understand the physics, that's not my question. My question is why E = mc^2 is always talked about in relation to nuclear physics when it doesn't seem to have any more consequence or practical use particular to that field than any other kind of energy change (chemical, physical, whatever). |
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Mass deficit in chemical reactions is about 10^-12 grams. Using E=mc^2 for chemical reactions is certainly nothing more than an academic exercise, it has no practical meaning. |
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The mass difference is still pretty small, I remember figures of the initial and final masses had to be accurate to a large number of figures to have any use. |
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I really think you're splitting hairs here. their are all sorts of causal factors involved. Suppose a prank gets out of control and I accidentally end up dropping a nuke on your house. If someone asks you why you don't have a house anymore, it would be perfectly reasonable for you to reply that one gram of uranium was converted to one gram of electromagnetic radiation and heat on top of your house and so now you don't have a house. How I got that conversion to occur may or may not be of interest. |
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Last edited by PhilosopherStoned; 08-04-2010 at 03:02 AM.
Previously PhilosopherStoned
Hmm no, I'd say the causal factor is subatomic particles falling into a lower energy state via their interactions with the strong and electromagnetic force. |
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