  Complementarity tells us we cannot know precisely the values of all the
properties of a quantum object at the same time: the precise determination of
one property implies that the value of some other (complementary) property is
undefined. E.g.the precise knowledge of the position of a particle implies that
its momentum is undefined. Here we show that a Schroedinger cat has a well
defined value of a property that is complementary to its ``being dead or
alive'' property. Then, thanks to complementarity, it has an undefined value of
the property ``being dead or alive''.
  In other words, the cat paradox is explained through quantum complementarity:
of its many complementary properties, any quantum system, such as a cat, can
have a well defined value only of one at a time. Schroedinger's cat has a
definite value of a property which is complementary to ``being dead or alive'',
so it is neither dead nor alive. Figuratively one can say it is both dead and
alive. While this interpretation only uses textbook concepts (the Copenhagen
interpretation), apparently it has never explicitly appeared in the literature.
We detail how to build an Arduino based simulation of Schroedinger's experiment
based on these concepts for science outreach events.
