Abstract
The ability of critical and reflexive thinking is necessary not only for the learning process, in the labor market employers also appreciate specialists who are able to make reasoned decisions, adapt, think and analyze their own and the actions of others. Many methods declare the development of critical thinking in students of higher educational institutions, but, unfortunately, do not measure the actual progress using verified methods for assessing the level of critical thinking. The article offers the results of a study of the effectiveness of the allocated course, aimed at the development of critical thinking among future chemistry teachers. A dedicated course of special seminars aimed at developing critical thinking conducted entirely in an online format in the first months of the COVID-19 pandemic, and considered as an online course using limited methods, but no less effective. The effectiveness of the special seminar course tested by adapting selected questions from the Watson-Glazer questionnaire before and after the course for the control and experimental groups. Then, by comparing the relative values, it was found that for the main five targets (evaluation of approval, interpretation, recognition of assumptions, deduction and the ability to draw conclusions), the experimental group showed an increase compared to the control group. It is prove that the students with whom the course passed, in absolute terms, showed an improvement in all measured parameters by 34% compared with the control group.