[thedoc]

First lawThe first law of thermodynamics may be expressed by several forms of the fundamental thermodynamic relation for a closed system:

Increase in internal energy of a system = heat supplied to the system - work done by the system.
For a thermodynamic cycle, the net heat supplied to the system equals the net work done by the system.
The net change in internal energy is the energy that flows in as heat minus the energy that flows out as the work that the system performs on its environment. Work and heat are not defined as separately conserved quantities; they refer only to processes of exchange of energy.

These statements entail that the internal energy obeys the principle of conservation of energy. The principle of conservation of energy may be stated in several ways:

Energy can be neither created nor destroyed. It can only change forms.In any process in an isolated system, the total energy remains the same.


Who else thinks Peacegirl will just hand-wave this away and say it is one of those ideas that needs to be re-examined and tested in light of efferent vision?

While this applies to energy, I believe that the same principle has been applied to matter so that 'Matter can be neither created or destroyed but can only change form', and now with atomic theory that would include matter changing to energy and energy changing to matter in some extreme cases.