In this paper we present a critical analysis of some of the arguments of flat Earth theory, and we also try to show that this analysis and refutation of these false claims can be a useful exercise in critical thinking that is so much needed today. This article can also make it easier for teachers who are exposed to some of the arguments of flat Earth theory by their students. Some arguments of this theory are completely senseless, and some can simply be disproved by trigonometry or basic physical laws.

There are only a few experiments in astrophysics that can be done in the high school environment. Some astronomical observations leading to the estimate of determining the values of various astronomical parameters (radius of the Earth, the Earth-Moon distance, and others) can be done, but the astrophysical measurements usually require specialised equipment, which is beyond the capabilities of most schools. This frontline describes three simple methods that can be used to estimate the solar constant, which is an important astrophysical parameter.

Seismo-ionospheric coupling is a field of great interest and is currently subject to rigorous study; using both ground and satellite data and many phenomenological features, the ionospheric precursors of earthquakes were identified. In this work, we present methods to study the stochastic properties of the lower ionosphere, derived from the data obtained with very low frequency (VLF) receivers at frequencies in the range of 19.6 to 37.5 kHz. Two main approaches are described: auto-correlation and random matrix theory treatments of amplitude time series data. It is shown that before shallow earthquakes with magnitudes greater than four, there are measurable changes that can be used in earthquake prediction. Although the exact form of the causal chain that leads to these changes are currently subject to diligent study, we believe that the investigations described herein are worth adding to the repertoire of ionospheric precursors.

In this paper, we discuss the theory of the operation and some practical considerations for the construction of an air ionization chamber, which can be used as a very simple detector of alpha particles. These detectors have several benefits compared to spinthariscopes and spark detectors. Classical experiments with ionization chamber detectors are presented. Ionization chambers equipped with a recording device, such as Arduino, are sensitive enough to evaluate the activity of lantern mantle alpha particle sources and uranium glass beads. Weak emitters are placed directly inside the chamber, which is then sealed with a shielding cap.

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