atomic mass unit (amu)

The atomic mass unit (amu) is a convenient way to measure the mass of atoms and subatomic particles. It is defined as exactly one-twelfth the mass of a carbon-12 atom, which is a common isotope of carbon. In practical terms, one amu is approximately equal to the weight of a single proton or neutron. This unit helps scientists easily compare the masses of different atoms and molecules, providing a standardized way to understand their relative sizes without using very large or small numbers. Essentially, amu simplifies discussing atomic scale masses.