Search

A significant approach that should be followed by physics teachers at the secondary education level in order to enhance students' understanding is to highlight the generality of the mathematical procedures that describe different physical phenomena. In this paper, the common procedure that is used to calculate the duration of various physical phenomena is presented. Examples from different scientific areas, from mechanics to circuit analysis and from nuclear physics to medicine are examined. In the presented examples, the magnitude of interest is always directly proportional to its rate of change. By 'grouping' physical phenomena that can be described using the same mathematical tools, the students' interest is enhanced and their physics perception is increased towards a deep understanding of the scientific methodology.

Electromagnetic radiation can be classified into two major types depending on its ability to detach electrons from atoms: ionising and non-ionising. The aforementioned categorization is significant due to the effects of ionising radiation on human tissue (e.g. carcinogenesis). However, many students around the globe cannot distinguish these two types of electromagnetic radiation and as a result significant misconceptions arise regarding this topic (for example radiation emitted by mobile phones is considered by many students as ionising). Hence, in this paper a teaching approach specifically designed and implemented for the secondary education level is presented, based on the absorbed energy distribution by atoms/molecules in each radiation type. More specifically, the number of atoms/molecules that absorb equal doses of energy per unit mass can be used in order to explain the difference in the effects caused by the two abovementioned radiation types. Also, two analogies from classical mechanics are presented to provide a full insight into the energy distribution concept from a teaching perspective.

When testing soft biological samples using the Atomic Force Microscopy (AFM) nanoindentation method, the force-indentation data is usually fitted to the equations provided by Hertzian mechanics. Nevertheless, a significant question remains up to date; is this a correct approach from a mathematical perspective? Biological materials are heterogeneous, so 'what do we calculate' when using a classic fitting approach? In this paper, conclusive answers to the abovementioned questions are provided. In addition, a new tool for the nanomechanical characterization of biological samples, the depth-dependent mechanical properties maps, is introduced., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Atomic Force Microscopy (AFM) nanoindentation is a powerful tool for the mechanical nano-characterization of biological samples. However, the range of Young's modulus values for the same type of samples usually varies significantly in the literature. This fact is partly related to the inhomogeneity of biological samples at the nanoscale and partly to significant mistakes during data processing. This review depicts that common errors related to (i) the real shape of the AFM tip, (ii) the range of data for which the sample presents an approximate linear elastic response, (iii) the sample's viscoelasticity, (iv) the sample's shape and (v) the substrate effects can be easily avoided without increasing the complexity of data processing. Thus, the present review paper focuses on the procedures that should be followed for the accurate processing of force-indentation curves regarding experiments on biological samples., (Copyright © 2022 Elsevier Ltd. All rights reserved.)