The **International System of Units (SI)** provides a standardized framework for [[Measurement|measuring]] physical quantities, ensuring consistency across scientific disciplines. SI units are based on fundamental constants of nature, such as the [[Speed of Light|speed of light]]. The seven base SI units—meter (m) for length, kilogram (kg) for mass, second (s) for time, ampere (A) for electric current, kelvin (K) for temperature, mole (mol) for amount of substance, and candela (cd) for luminous intensity—form the foundation of all other units. Some SI units are linked to and derived from [[Quantum Mechanics|quantum physics]]. For example, the kilogram is now defined using the [[Planck's Constant|Planck constant]], and the second is based on the frequency of radiation emitted by cesium-133 [[Atom|atoms]]. ![[SI_units.excalidraw.light.svg]] >[!read]- Further Reading >- [[Atomic Clocks]] >- [[Quantum Metrology]] >- [[Measurement]] >[!ref]- References