This article presents Swedish results from ‘the Relevance of Science Education’ (ROSE) study, which is a large world wide comparative research project based at the University of Oslo. The Swedish sample consisted of 751 students, most of whom were 15 years old, from 29 schools and data were collected inspring 2003. Student opinions about science lessons are presented in relation to enrolment intentions for upper secondary school together with what they want to learn about in science and technology.The findings indicate that secondary science instruction seems to address only a minority of the students, those that have chosen science or technology in their further education. At the same time, all students have interest in science and technology and many seem most interested in some important issues in societal development. The results are discussed from the perspective of learners and contribute to the debate about establishing a scientific literacy approach in compulsory education.
This paper highlights how results from large-scale studies can be used to understand students' knowledge of science. Several scholars express critique of today's PISA framework, especially with regard to the presentation of the results as national rankings, and suggest alternative and complementary methods. The present study has used PISA data to reveal hidden patterns in the results. The results show a general descending trend in items focusing on the nature of science and how new scientific knowledge is generated. On the other hand, there is an obvious upward trend regarding tasks that measure fact-based elementary or root knowledge. These trends are slightly differentiated at a national level, as the time and magnitude of the decline or increase may vary.
Abstract. The cloud detection performance of the cloud mask being used in the CM SAF cloud, albedo and surface radiation dataset from AVHRR data (CLARA-A2) cloud climate data record (CDR) has been evaluated in detail using cloud information from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) onboard the CALIPSO satellite. Validation results, including their global distribution, have been calculated from collocations of AVHRR and CALIOP measurements over a ten-year period (2006–2015). The sensitivity of the results to the cloud optical thicknesses of CALIOP-observed clouds were studied leading to the conclusion that the global cloud detection sensitivity (defined as the minimum cloud optical thickness for which 50 % of clouds could be detected) was estimated to 0.225. After applying this optical thickness threshold to the CALIOP cloud mask, results were found to be basically unbiased over most of the globe except over the polar regions where a considerably underestimation of cloudiness could be seen during the polar winter. The probability of detecting clouds in the polar winter could be as low as 50 % over the highest and coldest portions of Greenland and Antarctica, showing that also a large fraction of optically thick clouds remains undetected here. The study included an in-depth analysis of the probability of detecting a cloud as a function of the vertically integrated cloud optical thickness as well as of the cloud’s geographical position. Best results were achieved over oceanic surfaces at mid-to-high latitudes were at least 50 % of all clouds with an optical thickness down to a value of 0.075 were detected. Corresponding cloud detection sensitivities over land surfaces outside of the polar regions were generally larger than 0.2 with maximum values of approximately 0.5 over Sahara and the Arabian Peninsula. For polar land surfaces the values were close to 1 or higher with maximum values of 4.5 over the geographically highest parts of Greenland and Antarctica. The validation method is suggested to be applied also to other satellite-based CDRs and validation results are proposed to be used in Cloud Feedback Model Intercomparison Project (CFMIP) Observation Simulation Package (COSP) simulators for cloud detection characterisation of various cloud CDRs from passive imagery.
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