uncertainty principle

uncertainty principle

noun

Definition of UNCERTAINTY PRINCIPLE

: a principle in quantum mechanics: it is impossible to discern simultaneously and with high accuracy both the position and the momentum of a particle (as an electron) —called also Heisenberg uncertainty principle

First Known Use of UNCERTAINTY PRINCIPLE

1929

uncertainty principle

noun    (Concise Encyclopedia)

Principle that states that the position and velocity of an object cannot both be measured exactly at the same time, and that the concepts of exact position and exact velocity together have no meaning in nature. Articulated by Werner Heisenberg in 1927, it applies only at the small scales of atoms and subatomic particles and is not noticeable for macroscopic objects, such as moving vehicles. Any attempt to measure the velocity of a subatomic particle precisely will displace the particle in an unpredictable way, thus invalidating any simultaneous measurement of its position. This displacement is a result of the wave nature of particles (see wave-particle duality). The principle also applies to other related pairs of variables, such as energy and time.

Variants of UNCERTAINTY PRINCIPLE

uncertainty principle or Heisenberg uncertainty principle or indeterminacy principle