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The forces...do I have this right?

by maximiliano
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maximiliano
#1
Feb27-12, 10:47 PM
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So, I'm not in any way trained in any type of physics...so I'm sorry for the very basic way of explaining my question.

Energy released from burning firewood (for example). The way I think of this (and would explain it to someone) is that a chemical reaction is occurring, where hydrocarbons are being broken into their individual parts...that being hydrogen and carbon. The smoke I see is the carbon (and other stuff like water vapor). The heat I feel are the molecular bonds (energy) which were previously holding carbon and hydrogen together in a molecular fashion. Question/s- Is this incorrect....or essentially how it is working? Also.....where is the hydrogen going? Is that the fuel for the flame I see, combusting with the oxidizer in the air? Is the energy released from the weak force??

Energy released from an "atomic" (let's use fission for the example) explosion- Is the energy that is released a manifestation of the energy (strong force?) contained within the bonds which previously (pre-fission) held the atomic structure/parts (neutron, proton, electron) together?

Basically, I've always had it reasoned out in my head that fire/combustion is the release of the molecular bonds (previously holding the molecules together), while fission and fusion are releasing atomic bonds (previously holding the sub-atomic particles together). Am I out in left field?? I started thinking and reading about the weak and strong forces....which made me question the basic assumptions I have long kept....??
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cepheid
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Feb27-12, 11:04 PM
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Saying that the energy released was previously stored in chemical and nuclear bonds (respectively) in your two examples seems reasonable.

For nuclear fission, the nucleus of a heavy atom is broken up into two lighter nuclei. However, if you take the combined mass of the two lighter nuclei, you will get a number that is smaller than the mass of the original heavy nucleus. The shortfall, which is typically referred to as a "mass deficit" has been converted into energy, in accordance with the relation E = mc2.

Why was the heavier nucleus more massive in the first place than the two lighter elements that it split into? The extra energy was the nuclear binding energy i.e. it is the extra energy that (conceptually, at least) went into putting the heavy nucleus together. You might want to look up "binding energy" on Wikipedia or something, for some more insight.

The strong nuclear force is indeed the thing that holds protons and neutrons together in the nuclei of atoms. Therefore, it is the force that is doing the binding in this case.
Drakkith
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Feb27-12, 11:35 PM
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Quote Quote by maximiliano View Post
Energy released from burning firewood (for example). The way I think of this (and would explain it to someone) is that a chemical reaction is occurring, where hydrocarbons are being broken into their individual parts...that being hydrogen and carbon. The smoke I see is the carbon (and other stuff like water vapor). The heat I feel are the molecular bonds (energy) which were previously holding carbon and hydrogen together in a molecular fashion. Question/s- Is this incorrect....or essentially how it is working? Also.....where is the hydrogen going? Is that the fuel for the flame I see, combusting with the oxidizer in the air? Is the energy released from the weak force??
Generally the fuel is bonded with the oxidizer. In the case of hydrocarbons, such as Methane, CH4, both the carbon and hydrogen are bonded with oxygen to form carbon dioxide and 2 water molecules, H2O. However real combustion is never perfectly complete and various other oxides and wastes are produced along with carbon smoke and ash. The heat you feel is either infrared and visible light released or hot gasses from the process. The energy in the bonds is from the electromagnetic force, not the weak force.


Basically, I've always had it reasoned out in my head that fire/combustion is the release of the molecular bonds (previously holding the molecules together), while fission and fusion are releasing atomic bonds (previously holding the sub-atomic particles together). Am I out in left field?? I started thinking and reading about the weak and strong forces....which made me question the basic assumptions I have long kept....??
You are pretty much correct.

maximiliano
#4
Feb28-12, 12:14 AM
P: 43
The forces...do I have this right?

thanks folks! Okay.....so With fire....essentially I'm FEELING the electromagnet force (or what was the electromagnetic force); while with fission (and fusion) I'm essentially feeling the strong force....or what was the strong force.

Am I, in very layman's terms, basically correct so far....yes??

NOW, since we don't really understand gravitational force..........can you give me an example of the WEAK FORCE/INTERACTION??
Drakkith
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Feb28-12, 12:19 AM
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I'd say that's an alright non technical description, though its a little too inaccurate for my tastes.

An example of the weak force is beta decay. Look it up on wikipedia for more info.


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