Analyses of students’ ideas about the organ system in the human body and how these relate to their thoughts about living a healthy life are presented. The study concerns 9th grade students (15/16 years) in Sweden. The empirical data consists of drawings and answers to written questions, both open and multiple-choice, and interviews with students and teachers. Comparing explanations of a well known scenario (eating a sandwich) to other that are less often discussed (taking a painkiller and drinking water) we report that it is difficult for the students to transfer knowledge of pathways in the digestive system shown in explanations of the sandwich-scenario to the other scenarios. Most difficulties are shown for explanations of the drinking of water, since these explanations require connection of three different organ systems . More than half of the interviewed students believed that there is nutritious substance in water, but most of them were unable to specify what it would be. The students with the most developed understanding of the painkiller pathway were satisfied with taking medical substances to elude pain, and were not interested in other alternatives.

It has earlier been shown on a group level that it is difficult for 9th grade students (15-16 years old) in a Swedish school to understand how water is transported in the human body. The detailed analysis of five Swedish students in the 9th and final year of compulsory school concerning their ideas about water transportation is presented here. The empirical data consists of drawings, answers to a questionnaire with both open ended and multiple-choice questions, and student interviews. The analysis shows that all the students struggle to produce explanations involving the three organ systems: digestive, blood and excretion systems and they seem to use a variety of explanatory models as basis for their reasoning. Possible ways of understanding this are discussed together with implications for future teaching

In schools and in society it is argued about the importance of living a healthy life. The discus-sions are often focusing on different kinds of food. In this paper the focus is on students’ knowledge about the human body and how this is related to their thoughts about living a healthy life. 88 students in 9:th grade, in one Swedish school, were involved in the study. The study contains drawings and written questions, both open and multiple- choice, and interviews with students and teachers. We report that it is possible for the pupils to transfer knowledge from one context to another, (sandwich and painkiller) concerning pathways in the digestive system. But it is harder for them to connect different organ systems in their explanations, e.g. water's path through the body. More than half of the interviewed pupils believed that there is nutrition in water, but most of them were unable to specify what this nutrition consists of. It was also found that a few students believed that the body stores nutrition and energy when they skip a meal.

In both Sweden and South Africa, the science curriculum for the secondary level emphasizes learning about the functioning of the human body. Both curricula also emphasize the importance of living a healthy life. In this paper the focus is on how students’ ideas about the human body are constituted in explanations of three different scenarios, and in what way the students are transferring explanations between these scenarios. The study surveyed 161 9th grade students in five different schools in South Africa, and discusses the results in perspective of a previous study involving 88 students in Sweden. In both countries issues about body and health are discussed in several different subjects in school. The same data collection methods were used in both countries: drawings, written questions (open-ended and multiple-choice items), and interviews with selected students. The questions emerge from three scenarios: what happens in the body when you eat an open sandwich, drink water, and swallow a painkiller. We report that it is difficult for the students to horizontally transfer knowledge of the digestive system to other less well-known scenarios. In comparing the use of three systems in the painkiller-scenario to the horizontal transfer between the sandwichand the painkiller-scenarios we see that the difference is much less pronounced in South African results compared to the Swedish study. There are more similarities than differences between the results of this South Africa study and results obtained in Europe, but there are also differences especially with regard to non-scientific ideas about the human body.