To the memory of António Restivo who has not had the time to write his Fluid Mechanics, which would have been conceptual but containing, surely, many practical case studies 3 …when you can measure what you are speaking about and express it in numbers you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind. Preface The creation of knowledge is one of the essential components of the University mission. But it is fundamental that this knowledge should not be kept imprisoned within the institution itself. It must be transmitted so that society can benefit from it. The University of Porto, striving to be in the front line of universities at international level, claims full allegiance in its mission to these two components. The publication of results of the work developed by members of our academic community is a source of enjoyment to U.Porto for the contribution it brings to the fulfilment of its mission. Such publication deserves even higher prominence when it fills existing gaps in the available literature, while simultaneously opening excellent prospects for the dissemination of know-how, technologies and techniques not only to our own students but also to the public at large. The multimedia edition of "Laboratories of Instrumentation for Measurement" fully satisfies these requisites, deserving therefore our warmest applause, appreciation and incentive. This publication also possesses two special features that increase its added value. On one hand, it presents experimental and laboratory activities with an approach as close as possible to reality, even offering remote access to experiments, providing to the reader an excellent tool for learning laboratory techniques and methodologies. On the other hand, the adoption of electronic 6 format makes this work more easily available to a wider public. The authors should be highly praised for their initiative, as well as for all the sustained effort that culminated in this publication. This e-book fulfils every condition to be a success and hence to contribute to the prestige and the standing of U.Porto, being therefore worthy of its full acknowledgment. Prologue The publication of this e-book on "Laboratories of Instrumentation for Measurement" is most welcome given the scarcity of technical literature on this topic. It is also very timely because when dealing nowadays with large classes it is very difficult to provide to the students direct contact with …