Re: [Phys-l] Mass and Energy (Binding)

[Tom Sandin <sandint@ncat.edu>]

Since "binding energy" is (always?) defined as a positive quantity, I 
find it confusing. We can define it as

1) The minimum energy needed to separate the particles (which makes 
it, in my mind, the unbinding energy) and/or

2) As you say, the minimum energy released when the system is formed.

I think that the "binding energy" should actually be a negative 
quantity, but we are not going to change tradition.

Tom Sandin

At 1:32 PM +0300 5/25/06, Savinainen Antti wrote:
> Hi!
>
> Hugh wrote:
>
> "The difference, originally quaintly called the "mass defect," is,
> of course, the "binding energy" that serves to hold the nucleus 
> together. ... So where does the "binding energy" that holds these 
> particles together come from?"
>
> I'm a bit confused here. I have thought that the binding energy
> is the energy that a system *gives away* when bonds are formed;
> the bonding could be chemical, nuclear or whatever. The mass of
> the system decreases because part of the initial rest energy
> ('the mass defect') is transported to the surroundings or
> manifests itself as kinetic energy of the products. Isn't this
> the whole idea behind extracting nuclear power?
>
> So I wouldn't like to talk about the binding energy as if it
> were present in the system to keep it together. Should I correct
> my view?
>
> Regards,
>
> Antti
>
> Antti Savinainen
> Kuopio Lyseo High School
> Finland
> E-mail: <antti.savinainen@kuopio.fi>
> Website: <http://kotisivu.mtv3.fi/physics/>
>
>
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