First blank - physical or chemical
Second blank - less usable
The second law of thermodynamics states that whenever energy is converted from one form to another in a(n) physical or chemical change, we end up with less usable energy than before.
If we think of a simple steam system, which relies on a coal or wood fire to create the steam, even if we make our best attempts at insulating and decreasing the amount of escape of heat, we will undoubtedly have less energy in the heated water or steam through the physical change of the wood or coal into heat energy to heat the water to create the steam, in each of these physical changes we lose energy.
