Teachers' teaching practice plays a key role in the learning process of pupils, and for teaching to be successful, teachers must have knowledge in many different fields. This obviously also applies to teaching the subject technology. However, lower secondary school technology education in Sweden has reportedly been described in terms of teaching not following the curriculum along with widespread uncertainty among teachers regarding how to design their teaching practices. To address this national challenge, we need to understand the existing technology teaching practice. The purpose of this study is therefore to explore the considerations experienced technology teachers make. The study is based on interviews with technology teachers who work in lower secondary school (13--15-year-old pupils). The collected data consist of teacher's statements regarding their own expertise and teaching practice. To visualize the described teaching practice we have analysed collected data through the lens of pedagogical content knowledge (PCK). The results show both similarities and differences in the teachers' descriptions. Speaking in terms of PCK, the purpose and teaching focus expressed by the respondents, framed within the category `Orientations to teach technology', vary considerably. However, regarding `instructional strategies', the consensus among those experienced teachers is striking. Experienced technology teachers' teaching practices are proven to provide valuable information about the subject's potential, and the findings offer a basis for the future development of the subject of technology as well as future teacher education and professional development courses.

Within technology education in compulsory school in Sweden, materials are part of the core contents. What kinds of materials, and which characteristics that should be highlighted is open to interpretation. The study includes three sub-studies: 1/ An analysis of classroom activities during two lessons about materials in primary school, 2/ A Delphi study (Osborne et al. 2003) with experts on materials to gather their thoughts about materials in elementary technology education, and 3/ A review of text books. The purpose of this study is to put light on the field of materials as a content area by investigating what aspects of materials are highlighted in the three contexts. Two teaching sessions were video recorded. The data analysis focused on the content highlighted by teachers and students. Results suggest that the teachers and students highlight different aspects of materials. Nine experts participated in the first round of the Delphi study. All data were coded reflexively and iteratively. Results indicate the following major categories of material-related subject content: materials’ usage, groups of materials, properties, creation and refinement, environmental aspects, and modern materials. The themes identified in the study could be seen as limited and concretized set of content, and thereby a guiding tool for technology teachers.

Engineering has been introduced as a subject area in schools all over the world during the last decades. The purpose and contents vary slightly, but are commonly based on an engineering design process – on methods for systematic problem solving and product development. Skills learnt during this work is thought to be transferable to everyday life, future careers, and other educational areas. Pre-university engineering education should also increase pupils’ interest in technology, science and/or mathematics. Engineering projects in school commonly deal with non-realistic problems, which lead to difficult challenges for teachers and pupils concerning the transfer of skills to contexts outside of school. Great hopes for engineering’s opportunities to improve pupils’ creativity, learning, initiative, collaboration, and autonomy are expressed in curricula, but no conclusive evidence for its effectiveness exists.

Socio-technical systems are studied in compulsory school (pupils aged 7–16) in Sweden. The purpose is to increase pupils’ understanding of how technology and society affect one another by highlighting the interaction between technological artefacts, humans, institutions, and society at large. Many teachers find this subject difficult to teach, and therefore avoid it. To rectify this, a course module about socio-technical systems for teachers was instigated at KTH Royal Institute of Technology in Stockholm. This study was conducted during that course, and shows that teachers are affected by their educational backgrounds in their understanding of the systems; those who are trained in social sciences prioritize different aspects of the systems in their teaching than do those who have started out in the natural sciences. It also shows that the formulation of learning objectives in this area is very difficult for most teachers and few students include goals that relate to more general knowledge in areas such as genderrelated issues, historical aspects or environmental issues. Few of the students showed the ability to create a varied learning environment; searching information on the Internet and writing reports dominate the students’ suggestions. Understanding of socio-technical systems has the potential to bridge the gap between engineering and various aspects of society in education. It is therefore an essential part of technological literacy, and teacher training in the area should be improved.

A wide variety of skills, abilities and knowledge are used in technological activities such as engineering design. Together, they enable problem solving and artefact creation. Gilbert Ryle’s division of knowledge into knowing how and knowing that is often referred to when discussing this technological knowledge. Ryle’s view has been questioned and criticised by those who claim that there is only one type, for instance, Jason Stanley and Timothy Williamson who claim that knowing how is really a form of knowing that and Stephen Hetherington who claims that knowing that isknowing how. Neither Ryle himself nor any of his critics have discussed technological knowledge. Exposing both Ryle’s and his critics’ ideas to technological knowledge show that there are strong reasons to keep the knowing how–knowing that dichotomy in technological contexts. The main reasons are that they are justified in different ways, that Stanley’s and Williamson’s ideas have great difficulties to account for learning of technological knowing how through training, and thatknowing that is susceptible to Gettier problems, which technological knowing how is not.

In processes of engineering design and innovation, technological experiments are commonly conducted. The methods used are similar to those in the natural sciences, but the objectives are different. Technological experiments commonly deal with context-dependent problems related to function, rather than the uncovering or falsification of general laws. Furthermore, they often include value-laden concepts such as safety and ergonomics which are not part of the natural sciences. In school, experimentation is largely seen as part of the domain of the natural sciences, and the experimental parts of technological work gets little attention. This study is based on findings from a professional development course for teachers in years 7 to 9 in compulsory school in Sweden (pupils aged 13–16). In the course, the use of experiments in education was one of the major themes. The teachers who partook in the course generally found it difficult to formulate technological problems to be examined using experimental methods. During the course, they were to develop their own technology education experiments. These often turned out to be rather plain activities where the results, rather than the process were the important thing. In this paper, the results from the teachers’ actual attempts to design technological experiments and reasons for why experimentation should get a more prominent position in school are discussed. Experimental work is an essential part of research in engineering design and the technological sciences and should therefore be included in technology education, but without turning it into only applied natural science.

Swedish technology teachers’ views of technological knowledge are examined through a written survey and a series of interviews. The study indicates that technology teachers’ understandings of what constitutes technological knowledge and how it is justified vary considerably. The philosophical discussions on the topic are unknown to them. This lack of a proper framework for what constitutes technological knowledge and how it is justified might affect both how curricula are interpreted and how pupils’ knowledge is assessed.

Technological knowledge is of many different kinds, from experience-based know-how in the crafts to science-based knowledge in modern engineering. It is inherently oriented towards being useful in technological activities, such as manufacturing and engineering design.

The purpose of this thesis is to highlight special characteristics of technological knowledge and how these affect how technology should be taught in school. It consists of an introduction, a summary in Swedish, and five papers:

Paper I is about rules of thumb, which are simple instructions, used to guide actions toward a specific result, without need of advanced knowledge. One off the major advantages of rules of thumb is the ease with which they can be learnt. One of their major disadvantages is that they cannot easily be adjusted to new situations or conditions.

Paper II describes how Gilbert Ryle's distinction between knowing how and knowing that is applicable in the technological domain. Knowing how and knowing that are commonly used together, but there are important differences between them which motivate why they should be regarded as different types: they are learnt in different ways, justified in different ways, and knowing that is susceptible to Gettier type problems which technological knowing how is not.

Paper III is based on a survey about how Swedish technology teachers understand the concept of technological knowledge. Their opinions show an extensive variation, and they have no common terminology for describing the knowledge.

Paper IV deals with non-scientific models that are commonly used by engineers, based on for example folk theories or obsolete science. These should be included in technology education if it is to resemble real technology. Different, and partly contradictory, epistemological frameworks must be used in different school subjects. This leads to major pedagogical challenges, but also to opportunities to clarify the differences between technology and the natural sciences and between models and reality.

Paper V is about explanation, prediction, and the use of models in technology education. Explanations and models in technology differ from those in the natural sciences in that they have to include users' actions and intentions.