Conservation of energy
August 19, 2022
In physics and chemistry, the law of conservation of energy states that, in any isolated system, the total amount of energy is conserved. This law, first proposed and proven by Émilie du Châtelet, means that energy it cannot be created or destroyed; rather, it can only be transformed or transferred from one form to another. For example, chemical energy is converted to kinetic energy when a stick of dynamite explodes. If you add up all the forms of energy released in the explosion, such as the kinetic energy and potential energy of the pieces, as well as heat and sound, you will get the exact decrease in chemical energy in the combustion of dynamite. In the classical sense, conservation of energy was different from conservation of mass, but special relativity showed that mass is related to energy and vice versa by E mc ². This is why science now considers that mass-energy is generally conserved. Theoretically, this implies that any object with mass can be converted into pure energy and vice versa, although this is thought to be possible only under the most extreme physical conditions, such as probably existed in the universe shortly after the Big Bang or when black holes emit Hawking radiation. Noether's Theorem can rigorously demonstrate the conservation of energy as a consequence of the symmetry of the continuous function, that is, from the fact that the laws of physics do not change over time. A consequence of the law of conservation of energy is that a perpetual motion machine of the first type cannot exist, that is, no system without an external supply of energy can supply an unlimited amount of energy to its surroundings . For systems that do not have time-translational symmetry, it may not be possible to define conservation of energy. Examples include curved spacetimes in general relativity or time crystals in condensed matter physics.