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:
“But often the presence of mind and energy of a person remote from the spotlight decide the course of history for centuries to come.”
—Stefan Zweig (18811942)
“Just as we are learning to value and conserve the air we breathe, the water we drink, the energy we use, we must learn to value and conserve our capacity for nurture. Otherwise, in the name of human potential we will slowly but surely erode the source of our humanity.”
—Elaine Heffner (20th century)
“While the State becomes inflated and hypertrophied in order to obtain a firm enough grip upon individuals, but without succeeding, the latter, without mutual relationships, tumble over one another like so many liquid molecules, encountering no central energy to retain, fix and organize them.”
—Emile Durkheim (1858–1917)