This module introduces some of the fundamental concepts of quantum mechanics. By studying applications of the principles of quantum mechanics to simple systems the course will provide a foundation for understanding topics such as energy quantisation, the uncertainty principle and quantum tunelling. These will be illustrated with descriptions of experiments and phenomena found in nature. The particular systems you will study, in order of increasing mathematical complexity, are: (i) Infinite 1-D quantum wells, (ii) Finite 1-D quantum wells, (iii) Simple Harmonic oscillators, (iv) Probability flux, (v) Finite potential barriers and quantum tunneling, (vi) The solution to the Hydrogen atom, (vii) Angular momentum in quantum mechanics, (viii) Time-independent perturbation theory, (ix) The expansion theorem.