Home Page Overview Site Map Index Appendix Illustration About Contact Update FAQ


Uncertainty Principle

The Uncertainty Principle is derived from three elements: the wave-particle duality, the indivisibility of energy and momentum transfers, and the
Uncertainty lack of complete determinism. It states that for a pair of conjugate variables such as position / momentum and time/energy (including the rest mass energy mc2), it is impossible to have a precisely determined value of each member of the pair at the same time. This statement is illustrated with a schematic diagram in Figure 12-02. The corresponding formula is: x px > , where denotes the uncertainty, x is the position of the point mass m along the x-axis, px = m vx is the momentum along the x-axis, vx is the velocity along the x-axis, and = h/2 = 1.054x10-27 erg-sec. A similar relation exists for the uncertainty of the time t and energy E, e.g., t E > . In case of heavy mass (such

Figure 12-02 Uncertainty Principle [view large image]

as a macroscopic object), the uncertainties and thus the quantum effect becomes very small, classical physics is applicable once more. See "A Derivation of the Uncertainty Principle" for more detail.

Go to Next Section
 or to Top of Page to Select
 or to Main Menu