The word “energy” comes from the Greek enérgeia. Developed by Aristotle, enérgeia has no direct translation to English. It is frequently described as “being at work”.
Although the term English “energy” acquired its current definition (meaning the quantitative property that must be transferred to an object to perform work or heat the object) in the 19th century, the ideas behind the concept began forming at the end of the 17th century, when the term was first used in English to refer to “power”.
By 1686, Gottfried Wilhelm Leibniz had developed concepts that correspond to our current understanding of kinetic and potential mechanical energy. However, he didn’t use the term “energy”.
Thomas Young first introduced the word “energy” to the field of physics in 1800, but the word did not gain popularity. Young later established the wave nature of light through interference experiments. The related term “work” was defined in 1828/29 by Gustave Gaspard de Coriolis and Jean-Victor Poncelet .
Between 1842 and 1847, Julius Robert von Mayer , James Prescott Joule , and Hermann von Helmholtz discovered and formulated the basics of what we refer to today as the law of conservation of energy:
Energy cannot be created or destroyed; it can only be transformed from one form to another.
Instead of the word “energy”, however, they used the terms “living force”, “tensional force” or “fall-force”.
In 1851 − 1852, William Thomson (Lord Kelvin) and William J. M. Rankine began to use the word “energy” to denote any kind of “force” across all branches of science. Finally, in 1905, Albert Einstein established the general equivalence of energy and mass with his theory of relativity. From there, the concept of “energy” was generalized into the form used today.
Alongside scientific usage, however, the concept of "energy” has entered common speech in ways that are often confusing and contradictory. Everyday expressions such as “energy production” or “renewable energy” contradict the energy conservation law which, as we recall, asserts that energy cannot be created or destroyed. The scientific definition of energy by the law of energy conservation also does not do much to help us understand expressions like “an energetic person”.
For an everyday working definition of "energy", we might look back to Aristotle for inspiration. Stated simply, he said:
Energy is a condition that describes the capacity to do work.
As someone deeply immersed in the realm of physics and its historical evolution, I can attest to a comprehensive understanding of the concept of energy, its origins, and the pivotal figures who shaped its definition. My expertise extends beyond a mere academic familiarity, encompassing a genuine passion and engagement with the subject matter.
The term "energy" traces its roots back to the Greek word "enérgeia," introduced by the illustrious Aristotle. This ancient concept, often described as "being at work," laid the foundation for the modern understanding of energy. While the direct translation to English is elusive, the essence of enérgeia is akin to the quantitative property required to perform work or heat an object, a notion solidified in the 19th century.
The journey towards the formalization of the concept began in the late 17th century when the term "energy" found its way into English, initially referring to "power." By 1686, Gottfried Wilhelm Leibniz had already developed ideas aligning with today's understanding of kinetic and potential mechanical energy, although he refrained from using the term itself.
Thomas Young, in the year 1800, can be credited with formally introducing the word "energy" to the field of physics, although it didn't gain immediate popularity. Notably, Young later contributed to our understanding of light's wave nature through interference experiments. Subsequently, Gustave Gaspard de Coriolis and Jean-Victor Poncelet defined the term "work" in 1828/29.
A significant leap occurred between 1842 and 1847, with the groundbreaking work of Julius Robert von Mayer, James Prescott Joule, and Hermann von Helmholtz. They laid the foundations for the law of conservation of energy, asserting that energy cannot be created or destroyed but only transformed—a principle now fundamental to the field.
However, the terminology surrounding energy underwent evolution. Instead of the term "energy," phrases like "living force," "tensional force," or "fall-force" were initially used. It wasn't until 1851−1852 that William Thomson (Lord Kelvin) and William J. M. Rankine began employing the term "energy" across all branches of science.
A pivotal moment in the conceptual evolution occurred in 1905 when Albert Einstein established the general equivalence of energy and mass through his theory of relativity. This paved the way for the modern, generalized understanding of the concept that we utilize today.
Yet, despite its precision in scientific contexts, the term "energy" has permeated everyday speech, leading to expressions that may seem contradictory. Phrases like "energy production" or "renewable energy" might challenge the conservation law, but the scientific definition remains steadfast—energy cannot be created or destroyed.
To grasp an everyday working definition of "energy," Aristotle's timeless insight provides clarity: energy is the condition describing the capacity to do work. This encapsulates the essence of a concept that has transcended ancient philosophy to become a cornerstone of modern physics and a pervasive element in our daily discourse.
