Who, as a trainer, has never heard this irritating leitmotiv on the lips of those who work in the area? Therefore, each of them is convinced that the other is wrong or does not do what he should. Beyond the anecdote, the problem of the difficult conjunction between school and the real world is posed. Two places and two logics: the first one is concerned with learning, the second one considers production as its daily objective. But the words of our imaginary interlocutor also remind us of the confrontation between two fields: theory and practice and their apparently irrecondilable nature. Two disconnected worlds in which the students come and go with the frequent impression that they live two lives. There is a lot of professional literature on the subject of the "hands on" theory of education. The pedagogical device to which we refer enables the trainee to eventually make a link between what he learns at school and what he does during his training period. Once this has been asserted, it seems to us that the problem still remains unresolved. How can you create links between theory and practice? Which skills are required for the trainers? Which training device is necessary? The hypothesis of the paper we are presenting is that the question of work is at the centre of the problematics of "hands on" education. Work appears as the interface between the world of school and the one of field work. This assertion means that the practive produces knowledge just as research does and we must therefore accept that the practitioners carry on their work thanks to the accumulation, the construction and the transmission of this practical knowledge. Assuming that the question of work serves as a link between theory and practive means reconciling the vision of the teacher and the one of the practitioner. It implies that the trainer must make the effort of going on the field to observe, to understand and formalize what this knowledge coming from the daily experience is made of. This know-how is the result of the mobilization of the intelligence of the operators who are faced all the time with the hazards of real life. In the following work, we intend to put a pedagogical practice to the test of reality, according to the above mentioned hypothesis, to test its effectivity, to sort out the possibilities of change it enables it imposes and to mark its limits. Our wish is not to make the absolute proof of the validity of a point of view. We know by experience that the reality often escapes its observer and that trying to get in contact with it to possibly change it, means that you must be faced with it through action, and you must admit that success will not always be the result of your attempts.