Abstract:

The author of the new proposed didactic method has described in the article the idea of introducing the internal forces of „Euler's thought“ to the subject of Strength elasticity. Based on these internal forces, normal and tangential stresses are defined pertaining to the plane of the imaginary cut. Understanding this principle is fundamental to students. Three didactic methods are described in the article. The first method is based on a slice of potato, the second uses steel fries of Johansson's gauges, and the third uses a newly developed school demonstration device to model the internal forces of Euler's thought cut. The internal forces, representing the interaction of separate parts of the actual body with the Euler thought cut, are modeled and visualized using colored fibres with springs. The tension of the springs is proportional to the size of the internal forces over the cross-section. The presented didactic method can be used in learning of physic as well as technical subject in secondary school and in universities.

Keywords:

Object strength and elasticity, external force, internal force, Euler's imaginary cut, normal stress, tangential stress, Johansson measures.