History of energy

In the history of physics, the history of energy examines the gradual development of energy as a central scientific concept. Classical mechanics was initially understood through the study of motion and force by thinkers like Galileo Galilei and Isaac Newton, the importance of the concept of energy was made clear in the 19th century with the principles of thermodynamics, particularly the conservation of energy which established that energy cannot be created or destroyed, only transformed. In the 20th century Albert Einstein's mass–energy equivalence expanded this understanding by linking mass and energy, and quantum mechanics introduced quantized energy levels. Today, energy is recognized as a fundamental conserved quantity across all domains of physics, underlying both classical and quantum phenomena.