Teaching physics, chemistry, natural sciences and technology is based on interrogation, investigation and looking for answers which are gradually developed and enriched. We explain scientific procedures to our pupils thanks to what they learn abilities which are important for studying sciences but which may also be applied in other subjects. The aim is to learn to think independently and be able to identify a problem based on their own reflection, formulate hypotheses and draw conclusions from experimental findings. Using this method, they train their critical thinking. Our pedagogical practice therefore involves experimenting, taking into consideration historical relations, making connections with other disciplines and using new technologies.