Also known as Heisenberg's uncertainty principle) is a fundamental concept in quantum mechanics. It states that there is a limit to how precisely certain pairs of physical properties, such as position and momentum, can be simultaneously known.

The uncertainty principle is mathematically expressed as Δx * Δp ≥ h/4π, where Δx represents the uncertainty in measuring the position of a particle, Δp represents the uncertainty in measuring the momentum of a particle, and h is the reduced Planck constant.

This principle implies that the more accurately the position of a particle is measured, the less accurately its momentum can be known, and vice versa. In other words, there is an inherent trade-off between the precision with which these two properties can be simultaneously determined.

This uncertainty is not due to experimental limitations or technological constraints, but rather is a fundamental feature of the quantum nature of particles. It arises from the wave-particle duality of quantum mechanics, which states that particles can exhibit both wave-like and particle-like behavior.

The uncertainty principle has profound implications for the behavior of microscopic particles and has been experimentally confirmed in numerous experiments. It has led to the development of new theories and interpretations of quantum mechanics, such as the Copenhagen interpretation, which states that particles do not possess definite properties until they are measured.

Overall, the uncertainty principle is a fundamental concept in quantum mechanics that places a limit on the precision with which certain pairs of physical properties can be simultaneously known. It reflects the inherent uncertainty and indeterminacy of the quantum world.