In order to fix some important concepts of Fundamental Physics, either because they are not usually discussed in depth in theoretical classes and much less at laboratories, or because they are not sufficiently developed in textbooks, it is more effective not to tackle them directly, but to propose a mental or practical experiment to attract the…

According to Newtonian mechanics, the gravitational fields created by bodies with spherical symmetry (such as planets) are non-uniform. This may create the impression to undergraduate physics students that uniform gravitational fields are just an approximation. This is not the case as uniform gravitational fields are created in hollows of…

A popular physics legend holds that scissors can cut paper with a speed faster than light. Here this counter-intuitive myth is investigated theoretically using four simple examples of scissors. For simplicity, all cases will involve a static lower scissors blade that remains horizontal just under the paper. In the first case, the upper blade will…