Biology Question:?

Question

The first law of thermodynamics seems to conflict with what we know about ourselves. For example, after strenuous exercise we run out of "energy". We must eat to replenish our energystores. Where has that energy gone? Where has that energy gone? What form has it taken?

Answer 1

One of the important considerations that often gets left out of thermodynamic laws is the phrase, 'in a closed system'.

This is important because if energy can move in an out of a system, then of course it's possible for much of the energy to leave or any of the other thermodynamic laws to seem to be violated.

So the energy you lose from your body gets placed out into the world. If you are doing work, then that work is probably where the energy is (i.e. potential energy). Even if you just dug holes and filled them in, the energy was dissipated through sound, heat, and so on.

As far as science can determine, none of it is destroyed, though it is often ends up in a form we can no longer use. So it goes.