Energy
In physics, energy (Ancient Greek: ἐνέργεια energeia "activity, operation") is an indirectly observed quantity that is often understood as the ability of a physical system to do work on other physical systems. However, this must be understood as an overly simplified definition, as the laws of thermodynamics demonstrate that not all energy can perform work. Depending on the boundaries of the physical system in question, energy as understood in the above definition may sometimes be better described by concepts such as exergy, emergy and thermodynamic free energy. Therefore, in the words of Richard Feynman, "It is important to realize that in physics today, we have no knowledge what energy is. We do not have a picture that energy comes in little blobs of a definite amount." However, it is clear that energy is always an indispensable prerequisite for performing work, and the concept has great importance in natural science.
Read more about Energy.
Famous quotes containing the word energy:
“Three elements go to make up an idea. The first is its intrinsic quality as a feeling. The second is the energy with which it affects other ideas, an energy which is infinite in the here-and-nowness of immediate sensation, finite and relative in the recency of the past. The third element is the tendency of an idea to bring along other ideas with it.”
—Charles Sanders Peirce (1839–1914)
“The scholar may be sure that he writes the tougher truth for the calluses on his palms. They give firmness to the sentence. Indeed, the mind never makes a great and successful effort, without a corresponding energy of the body.”
—Henry David Thoreau (1817–1862)
“The persons who constitute the natural aristocracy, are not found in the actual aristocracy, or, only on its edge; as the chemical energy of the spectrum is found to be greatest just outside of the spectrum.”
—Ralph Waldo Emerson (1803–1882)