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.
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Famous quotes containing the word energy:
“There are no accidents, only nature throwing her weight around. Even the bomb merely releases energy that nature has put there. Nuclear war would be just a spark in the grandeur of space. Nor can radiation “alter” nature: she will absorb it all. After the bomb, nature will pick up the cards we have spilled, shuffle them, and begin her game again.”
—Camille Paglia (b. 1947)
“Violence among young people ... is an aspect of their desire to create. They don’t know how to use their energy creatively so they do the opposite and destroy.”
—Anthony Burgess (b. 1917)
“Children are intensely invested in getting their way. They will devote more emotional and intellectual energy to winning arguments than parents ever will, and are almost always better rested.”
—Jean Callahan (20th century)