"This can be stated as follows: Energy cannot be created nor destroyed.
The one exception is in nuclear reactions where mass is turned into
energy, and as we have seen, this occurs only in the center of stars and
in nuclear reactors."
"Energy is neither destroyed nor created. This basic principle is known
as the law of conservation of energy. The only time this law seems to be
violated is when energy is "released" in nuclear reactions. In a nuclear
reaction, the center, or nucleus, of an atom changes. It might join with
another atom (fusion) or give off particles (radioactive decay) and turn
from one kind of atom into another. In a nuclear reaction a very small
amount of matter disappears, and an equivalent amount of energy
appears."
It is my understanding that energy is always conserved, even in nuclear
reactions. The mass-energy equivalence is really between the
"potential" energy and the mass, so it is the *kinetic* energy that is
not conserved during nuclear reactions, not the *total* energy. I have
no problem with that but then the same could be said for other types of
reactions as well, like chemical and gravitational, so what is the point
of implying that nuclear reactions are the exception?
Am I off-base here?
If not, could I just say it "appears" or "seems" to be violated (as
stated in the second example)? I guess I am looking for a simple way to
use these materials without confusing the non-scientist readers.
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Robert A. Cohen, Department of Physics, East Stroudsburg University
570.422.3428 rcohen@po-box.esu.edu http://www.esu.edu/~bbq