This research aims to describe how pupils in compulsory school, boys and girls at an age between six and twelve years, apprehend how they form and develop concepts in technology and what they apprehend they learn.Few pupils, particularly girls, choose technological educations at higher levels, despite that the industry need engineers. In the Swedish curriculum from 1994 for the compulsory school, technology has got an own syllabus and has become a compulsory subject.In the on-going technical project a LEGO material is the tool. Most of the pupils have LEGO at home but not all of them, in particular those who are from foreign countries. The theoretical framework is based upon phenomenological theory. It is a longitudinal study over three years. Now it has gone two years of the project time. The children start with large LEGO-pieces, thereafter they use technique LEGO and finally the pupils build LEGO robots, which they program in a computer. The empirical data are collected in two compulsory schools. The pupils work two or three together in the classroom. Interviews, observations and diaries analysis from the on-going study shows that the goal of the first year was for the pupils to learn collaboration through problem solving with LEGO. The LEGO-material became an artefact for collaboration. The teachers had decided that goal and the pupils managed the goal. The following year I can see how the pupils make links between LEGO and technology. Boys have for instance found knowledge from the building with LEGO-material which they think they can use in the future when they will get a job. Many teachers have no own formal competence to teach technology, especially teachers who teach younger pupils. Nevertheless they have the responsibility for the technology subject with reaching the goals. The pupils cannot work without assistant from the teacher so the teacher has to be interested and to know much about technology to raise pupils' motivation of technology. The second aim of this study that is interesting for me is to get knowledge of how the teachers know and argue about how their pupils best form and develop concepts in technology.As I have followed the learning process in different practical situations I see a possibility to understand the pupils' apprehension how they form and develop concepts in technology out of teachers' strategies.