The Heisenberg uncertainty principle is the principle that the position and the momentum of a particle cannot both be known exactly at the same time: the more precisely one is fixed, the less precisely the other can be. It is a fundamental limit of nature, not merely a limitation of measurement. For electrons in atoms, it is why we describe their location by a probability distribution rather than a definite path.

海森堡不确定性原理是指粒子的位置和动量不能同时被精确确定:其中一个确定得越精确,另一个就越不精确。这是自然界的根本限制,而非仅仅是测量的局限。对于原子中的电子,这正是我们用概率分布而非确定轨迹来描述其位置的原因。