What is Uncertainty principle?
The '''Uncertainty principle''' is also called the [[Heisenberg uncertainty principle|Heisenberg's uncertainty principle]]. [[Werner Heisenberg]] [[wikt:stumble|stumbled]] on a secret of the universe: Nothing has a [[wikt:definite|definite]] [[wikt:position|position]], a definite [[wikt:trajectory|trajectory]], or a definite [[wikt:momentum|momentum]]. Trying to pin a thing down to one definite position will make its [[momentum]] less well pinned down, and [[wikt:vice-versa|vice-versa]]. In [[wikt:everyday|everyday]] life we can [[wikt:successfully|successfully]] measure the position of an automobile at a [[wikt:definite|definite]] time and then measure its [[wikt:direction|direction]] and [[wikt:speed|speed]] ([[wikt:assuming|assuming]] it is [[wikt:coast|coasting]] along at a steady rate) in the next few [[wikt:moments|moments]]. That is because the [[wikt:uncertain|uncertainties]] in position and velocity are so small that we could not [[wikt:detect|detect]] them. We assume, quite [[wikt:correctly|correctly]], that the [[wikt:trajectory|trajectory]] of the automobile will not be [[wikt:noticeable|noticeably]] changed when we drop a [[wikt:marker|marker]] on the ground and [[wikt:click|click]] a [[wikt:stopwatch|stopwatch]] at the same time to note the car's position in time and space. We may bring that experience to the world of [[wikt:atomic-sized|atomic-sized]] [[wikt:phenomenon|phenomena]] and [[wikt:incorrectly|incorrectly]] assume that if we [[wikt:measure|measure]] the position of something like an [[wikt:electron|electron]] as it moves along its trajectory it will [[wikt:continue|continue]] to move along that same trajectory, which we [[wikt:imagine|imagine]] we can then [[wikt:accurate|accurately]] [[wikt:detect|detect]] in the next few [[wikt:moments|moments]]. We need to learn that the electron did not have a definite position before we [[Locating (physics)|located]] it, and that it also did not have a definite momentum before we measured the trajectory. Moreover, we may [[wikt:justifiable|justifiab