The law of conservation of energy states that energy cannot be created or destroyed; it can only be transformed or transferred from one form to another. In an isolated system, the total amount of energy remains constant over time, even though energy may change forms such as from potential to kinetic energy or from mechanical energy to thermal energy. This principle is fundamental in physics and is also known as the first law of thermodynamics.
Key Points About the Law of Conservation of Energy
- Energy can neither be created nor destroyed in a closed system.
- Energy can change forms, such as kinetic energy to potential energy, chemical energy to thermal energy, etc.
- The total energy of an isolated system remains constant.
- This law applies universally in classical physics, thermodynamics, and quantum mechanics.
- Even when energy seems to "disappear" (e.g., due to friction), it is converted into other forms like thermal energy, thus conserving the total energy.
Example
A pendulum is a practical example: as it swings, its energy continually converts between potential energy (at the top of the swing) and kinetic energy (at the bottom). Although friction gradually slows the pendulum, converting mechanical energy into heat, the total amount of energy in the system remains unchanged.
This principle is foundational for understanding energy usage, transfer, and transformation in all scientific and engineering fields.
