Werner Heisenberg's uncertainty principle highlights a fundamental limitation in quantum mechanics: the simultaneous measurement of an electron's velocity and position is impossible. This principle asserts that if you accurately determine the speed of an electron, its exact location becomes uncertain, and vice versa. This phenomenon arises from the dual nature of electrons, which exhibit both wave-like and particle-like characteristics.
The wave nature of electrons relates to their velocity, similar to how light energy propagates as a wave. Conversely, the particle nature of electrons pertains to their position, akin to light being composed of discrete packets known as photons. This duality is encapsulated in the concept of complementarity, which posits that electrons can be observed as either particles or waves, but not both at the same time. This intrinsic property of matter is a cornerstone of quantum mechanics, illustrating the complex behavior of subatomic particles.