In this diploma thesis, a research on student scientific thinking and logical reasoning was carried out in two stages. The first stage was an assessment of 90 first year students at the Faculty of Electrical Engineering and Computing (FER), University of Zagreb conducted in 2017, using Lawson's test of scientific reasoning. The results showed that some students struggled with control of variables and hypothetical-deductive reasoning. In order to explore these student difficulties in more details, additional test items were constructed, and new assessment of 97 first year FER students was conducted in 2018. The analysis of students’ results on the Lawson’s test did not show any statistically significant difference between the two generations of students, so the unified data were further analyzed. Lawson’s test is composed of two tier multiple-choice items that ask for an answer and corresponding explanation, and they can be scored individually or in pairs. The percentage of correct answers was \( (78 \pm 14)\% \) for individual scoring, and it was \((70 \pm 17)\% \) for pair-scoring. Croatian students obtained somewhat better results than corresponding Chinese and U.S. students. As already mentioned, some students had difficulties with hypothetical-deductive reasoning and control of variables that was further investigated with additional test items. The percentage of correct answers on the additional part of the test was \((73 \pm 18)\%\) that confirmed student difficulties with these aspects of scientific reasoning. The results of this study suggest that inquiry-based teaching should be used more frequently.