brightside S9 wrote:
On Sun, 20 Sep 2009 18:56:58 +0100, "Norman Wells"
wrote:


Look, his formula can be used to calculate the energy that could
theoretically be released from a certain mass, or to calculate the
mass that could be formed from a certain amount of energy. And you
can do that with any mass or any amount of energy at any time. But
those calculations only have any significance or relevance if what
you're doing is actually converting mass into energy or vice versa.
And mass is not actually converted into energy on earth in any
processes except nuclear reactions and radioactive decay, whatever
you may think.

No you forgot chemical reactions. However because the change in mass
is so small and inperceptible, chemistry has aworkable law of
"Conservation of Mass", which is confusing *you*.

Common example given in physics text books is the explosion of 1kg of
dynamite. This results in a mass loss of about 0.6nkg and energy
release of 5.4MJ. So for chemistry the mass loss is *imperceptible*
but the energy release is obvious.

That's circular. The writers have assumed that e=mc^2 applies, calculated a
spurious result in a case where it clearly doesn't actually apply, and
concluded that chemical reactions therefore obey the formula.

Isn't it convenient that in all of these cases where e=mc^2 is erroneously
applied, the change of mass they say occurs can't actually be demonstrated
because it's always so 'imperciptibly small'?

If you consulted a _chemistry_ text book it would doubtless say that there
is no loss of mass at all, the energy coming not from destruction of matter,
which would be required for mass loss, but from the chemical reactions in
which compounds of high chemical energy combine to form compounds of lower
intrinsic energy.