  We present an approach for teaching quantum physics at high school level
based on the simplest quantum system - the single quantum bit (qubit). We show
that many central concepts of quantum mechanics, including the superposition
principle, the stochastic behavior and state change under measurements as well
as the Heisenberg uncertainty principle can be understood using simple
mathematics, and can be illustrated using catchy visualizations. We discuss
abstract features of a qubit in general, and consider possible physical
realizations as well as various applications, e.g. in quantum cryptography.
