The lack of consensus on the formulation of the concept of "critical thinking" has determined the existence of different approaches to teaching critical thinking, among which one can distinguish an "interdisciplinary" approach based on "universal" definitions and a disciplinary approach based on context-dependent definitions. The choice of approach largely depends on the educational traditions of the society. For the Russian educational community, which traditionally values subject knowledge, a disciplinary approach is more acceptable. Natural sciences have a high potential for the development of critical thinking due to their close relationship with informal logic and the scientific method. To realize this potential, it is necessary to change the goals of learning from memorizing and reproducing knowledge to shaping the thinking of a student who is able to find, evaluate, assimilate and apply this knowledge in new situations, creating innovations. This inevitably entails a change in the learning model. An important question is what should this model be? A model that relies on the essence of science as a process of discovering something new while following the scientific method is proposed. The model is based on a combination of the problem method and practical project activities. The problematic method is realized through a new type of assignments for natural science-natural science cases, which serve as simulators of "making discoveries" by recreating the situation of scientific search. Some cases reproduce situations of really perfect scientific discoveries (for example, the discoveries of Galileo and Mendeleev), and some suggest finding ideas for engineering and technological solutions to still unsolved problems (such natural science cases are called STEM-cases). Case assignments guide students along the path of the scientific method and serve as simulators for the development of those components of critical thinking that are included in the context-dependent definition of critical thinking (rationalism, logic, creativity, reflection and metacognitivism). STEM-cases are miniprojects carried out in small groups that prepare you to work on an individual project. The most important thing in an educational project is to go through all the stages of the scientific method and, as a result, get a product that has a certain degree of objective novelty-that is, innovation. Research involving students from three Moscow universities has shown that the «case + project» strategy has a positive effect on both the development of critical thinking components and the academic performance of students. © 2021 Nova Science Publishers, Inc.