Question

Explain the Heisenberg uncertainty principle [5]

Answer 1

Heisenberg uncertainty principle states that certain pairs of physical properties, like position and momentum, cannot both be known to arbitrary precision. That is, the more precisely one property is known, the less precisely the other can be known. This is not a statement about the limitations of a researcher's ability to measure particular quantities of a system, it is a statement about the nature of the system itself as described by the equations of quantum mechanics. According to the uncertainty principle, it is, for instance, impossible to measure simultaneously both position and velocity of a microscopic particle with any degree of accuracy or certainty.

For example:

You are in a car traveling at some speed.
The car may or may not move in a straight line, and your speed may or may not be constant.
While you can measure your speed or location, you can't know both at the same time. To measure your speed, your location must be changing, and to measure your location, your speed must be ignored or assumed rather than measured.
Source:
http://en.wikipedia.org/wiki/Heisenberg_...