  In this article a notion of information is presented which stresses the
contextuality of quantum objects and their measurement. Mathematically this is
reached by a quantification of the quantum mechanical surplus knowledge which
has been introduced by Weizsacker. This new formulation gives insight into
relation between single quantum objects and ensembles of quantum objects. The
goal is to provide an explanatory concept for teaching purposes, the
description of quantum processes and measurement with aid of information.
