The bond graph representation is an energy-based graphical language that has been first developed for the dynamic modelling of finite dimensional mechanical, hydraulic and electrical systems. As such, this interdisciplinary modelling approach was a 'mechatronic' approach 'avant-la-lettre'. It has been also applied to chemical engineering systems and, more recently. to infinite-dimensional systems models. Such an application is more directly related to the concepts of (irreversible) thermodynamics, even though all fields of applications implicitly satisfy the basic principles of thermodynamics. The aim of this paper is to present the bond graph language by using some rather simple dynamical systems as tutorial examples and to show the potentialities of this language to build dynamical models from reusable sub-models. Provided that software tools are available to manipulate this language, which is already the case for finite dimensional models at a commercial level and for infinite-dimensional models at a research level, it can be a solution to the problem of process model management during the process life that is encountered in the process industries. (C) 2007 Elsevier B.V. All rights reserved.