Use of different external mediating mechanisms of the Bohr atom model: Evidence of Meaningful Learning through verbal-gestural analysis in elementary school students

The present article sought to investigate if the use of different external mediation mechanisms to teach the Bohr Atom model in elementary education with the didactic methodology of the Potentially Significant Teaching Units (PSTU) can result in Meaningful learning. Therefore, we naturally use the theoretical contribution of the Ausubelian Meaningful Learning Theory, in particular by discussing elements that indicate evidence of meaningful learning. This theory was adopted with the purpose of understanding and analyzing whether or not there is evidence of meaningful learning with elementary level students after about a year of using the didactic methodology. The didactic methodology used was the application of didactic sequences inspired by the PSTU model, modified to be applied in Elementary School. We also use different external mediation mechanisms that independently reproduce the Bohr atom model, such as model building (psychophysical mediation), teacher explanation on a blackboard (social mediation), use of textbooks (cultural mediation) and computer simulations (hypercultural mediation). Data analysis was carried out through two semi-structured interviews according to the Report Aloud protocol followed by the depictive gestural analysis, performed with an interval of almost one year, both interviews were carried out after the application of the didactic methodology, in order to assess the retention of the learning residue. We argue that the students' verbal-gestural production indicates that there was meaningful learning of the Bohr Atom model, especially related to social and hypercultural mediations.

Interesting Examples of Violation of the Classical Equivalence Principle but Not of the Weak One

The equivalence principle (EP) and Schiff’s conjecture are discussed en passant, and the connection between the EP and quantum mechanics is then briefly analyzed. Two semiclassical violations of the classical equivalence principle (CEP) but not of the weak one (WEP), i.e., Greenberger gravitational Bohr atom and the tree-level scattering of different quantum particles by an external weak higher-order gravitational field, are thoroughly investigated afterwards. Next, two quantum examples of systems that agree with the WEP but not with the CEP, namely, COW experiment and free fall in a constant gravitational field of a massive object described by its wave-function Ψ, are discussed in detail. Keeping in mind that, among the four examples focused on in this work only COW experiment is based on an experimental test, some important details related to it are presented as well.