Potash, an essential raw material of the 18th century, used to be produced from the ashes of plants. Known since antiquity, it was in 1807 that Humphry Davy put an end to the decades-long controversy about its nature as a compound. The technology behind potash production was implemented in Brazil by the Portuguese naturalist Frei Velloso. The…

A creative apparatus for use in a hands-on laboratory experiment that allows the visualization of the vapor pressure as a function of temperature is described in this paper. Inspired by homemade barometers and using simple materials that are easily accessible for teaching laboratories, a lowcost system for the establishment of the vapor-pressure…

The Griess assay is widely used by regulation agencies as an official method for nitrite quantification in water and food samples. In Brazil, the official method, which has been used to determine nitrite in food, was described by Instituto Adolfo Lutz (283/IV) in 1984. It uses 8 mL of reactants and provides 50 mL (reactants plus sample) of waste…

Undergraduate-level laboratory experiments that involve the synthesis of nanomaterials with well-defined/controlled shapes are very attractive under the umbrella of nanotechnology education. Herein we describe a low-cost and facile experiment for the synthesis of Cu(OH)[subscript 2] and CuO nanowires comprising three main parts: (i) synthesis of…

Radon is a dangerous radioactive gas that is always present in the environment. It is important that students and society in general are aware of radon as a health hazard. This study describes a simple experiment to measure the variations of radon gas concentration outdoors. We compared the concentration of radon gas in the environment in dry and…

The digestive system is a fundamental topic in biological science teaching. Despite its importance, the level of students' knowledge on the topic appears to differ from recommended levels at several educational grades. Their knowledge also seems to be resistant to change; therefore, this discrepancy may be viewed as an epistemological obstacle to…

This experiment encourages students to use deductive reasoning skills to understand the correlation between different techniques used in a chemistry laboratory and to extract and analyze curcuminoids using natural products and processed food from a grocery store. Turmeric pigments were used to teach continuous or discontinuous extraction, vacuum…

A laboratory experiment has been developed to illustrate environmental and sustainability aspects, focusing on the wastewater treatment by means of superparamagnetic nanoparticles functionalized with humic acid. The experiment, conducted by a group of high school students, involves nanoparticle synthesis and minor characterization, followed by…

An experimental procedure is presented that was developed by fifth-year chemical engineering and industrial chemistry undergraduates at the Federal University of Rio de Janeiro doing the discipline on Experimental Organic Technology. The aim of this study was to apply the solvatochromic effect of the dye Nile Blue chloride to the characterization…

The COVID-19 Pandemic interrupted university activities at the beginning of the first semester of 2020, forcing the academic community to reinvent itself to meet the determinations of social isolation. The use of assistive technologies such as information and communication technologies has never been more welcome. However, for a college student…

This work describes a simple talking calorimeter for the visually impaired based on the Arduino Uno without any shield. An electronic interface was designed using a Wheatstone bridge, a thermistor, or an operational amplifier (opamp). The temperature values are communicated by a loudspeaker connected to pulse-width modulation (PWM) digital output…

Ionizing radiation one of modern physics experimental teaching in colleges and high school can be easily implemented today due to low coasts of detectors and also electronic circuits and data acquisition interfaces. First it is interesting to show to young's students what is ionizing radiation and from where they appears near ground level? How it…

The substitution of petroleum-based fuels with those from renewable sources has gained momentum worldwide. A UV-vis experiment for the quantitative analysis of biofuels (bioethanol or biodiesel) in (petroleum-based) diesel oil has been developed. Before the experiment, students were given a quiz on biofuels, and then they were asked to suggest a…

This paper evaluates the viability of using controversies in teaching. An educational project has been elaborated in which some historical-philosophical clashes were introduced into the classical syllabus of physics. The historical-philosophical controversy dealt with here, took place between the French physicists Biot and Ampere in the 19th…

Teaching collections are of great importance for science instruction at any level. There are several problems linked to the handling and curatorial management of this kind of collection. Among these is the relatively short life-span of specimens, due to the damage from continuous handling by students. Often the specimens used to replenish the…