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In undergraduate chemical thermodynamics teachers often include equations and view manipulations of variables as understanding. Undergraduate students are often not able to describe the meaning of these equations. In chemistry, enthalpy and its change are introduced to describe some features of chemical reactions. In the process of measuring heat at constant pressure, work is often disregarded. Therefore, we investigated how undergraduate students describe expansion work and technical work in relation to enthalpy and its change. Three empirical studies (n tot = 64, n tot = 22, n tot = 10) with undergraduate chemistry students taking their first or fifth chemistry course at two Swedish universities were conducted. Questions on enthalpy and its change, internal energy and its change, heat and work were administered in questionnaires, exam questions, hand-ins and interviews. An analytical matrix was developed and qualitative categories with respect to pressure and volume were formed. The results indicate that work in general and even more so expansion work and technical work are difficult processes to describe and relate to the definition and formula of enthalpy change. Work is mainly described without reference to pressure and volume. The properties of volume are more likely to be described correctly than the properties of pressure. The definition of enthalpy change at constant pressure is generalised to constant volume/varying pressure cases. This study gives further insight into the way in which students use pressure and volume as they describe expansion work and technical work as well as the contextual correctness of these descriptions. The matrix and categories can be used by researchers, teachers and students.

All-terrain vehicles (ATVs) are a group of machines that do not operate on prepared roads. Off-road use of these fast-moving machines results in the driver being exposed to high magnitudes of vibration and shock. It is estimated that there are up to 20,000 people in Sweden that uses ATVs during their work, such as forest machines, snowmobiles, snowgroomers, motorcycles, and three- and four-wheeled vehicles. The aim of this cross-sectional study was to investigate the risk for musculoskeletal symptoms of the neck, shoulders, upper and lower back among professional drivers of ATVs. Data from 215 male drivers of forest machines, 137 drivers of snowmobiles, 79 drivers of snowgroomers and 167 men randomly selected from the general population to act as a control group were collected. All subjects were from the four most northern counties in Sweden. Musculoskeletal symptoms during the previous year were assessed using the standardised Nordic questionnaire. Prevalence rate ratios were adjusted for age, smoking and job strain. Results showed that all driver categories had significantly increased prevalence rate ratios (1.5-2.9) for experiencing symptoms in the neck-shoulder and thoracic regions. Unlike findings from previous epidemiological studies, there was not an increased risk of low back pain among any of the driver categories compared to the control group. The higher prevalence of musculoskeletal problems is thought to be due to long-term exposure to physical factors, such as, whole-body vibration (WBV) and shock, static muscle overload and extreme body postures. The findings in this study highlight the fact that working with ATVs may cause, aggravate or prevent resolution of musculoskeletal symptoms. However, the exact cause of these problems is unclear and the interaction between vibration and body posture is not known. The authors believe however that it is necessary to reduce exposure to WBV and shock to decrease the high prevalence of musculoskeletal symptoms among professional ATV drivers. This may be done by implementing preventative measures, such as selecting the best vehicle model or seat, optimising driving style and minimizing use in rough terrain. Health surveillance seems to be important for people that regularly use ATVs in their work.

Technology has been a compulsory subject in the Swedish school curriculum since 1980. However, many primary school teachers say that they do not feel comfortable with teaching technology. This often results in a teaching time that is a (too) small part of the total teaching time of science and technology. In addition, studies show that pupils are probably not given equivalent education as the syllabi may be interpreted in different ways. Against this background, we have conducted three research circles under the guidance of researchers, in three municipalities in the Mälardalen region, addressing teachers working in preschool class to grade 6. Each circle had up to five participants and had five meetings during one year. Based on the teachers’ own questions and needs we have studied didactic literature connected to the subject of technology, discussed the syllabi for technology and different forms of teaching support. An existing model for pedagogical content knowledge in technology has been used to interpret the activities in the research circles. The teachers experienced and appreciated the opportunities to work with the subject content linked to the syllabi for technology and saw ways to integrate technology with other school subjects.