Antioxidants are molecules that act against free radicals, and this effect can bring many benefits to health and society. Antioxidants can be found in various matrices of nature, such as fruits and plants. Some studies have shown that "Rhizophora mangle," a typical mangrove plant, is rich in antioxidants. People report its use for…

Harmful plastic debris found on beaches and in the oceans are not limited to drinking straws or bags. There are several synthetic organic polymers that can be used to make different kinds of plastic materials and have resulted in billions of tons of waste that can reach the aquatic biome and are harmful to freshwater and marine communities as well…

This experiment describes a simple protocol for teaching acid-base titrations using potentiometry, conductivity, and/or photometry to determine end points without an added indicator. The chosen example examines the titratable acidity of a red wine with NaOH. Wines contain anthocyanins, the colors of which change with pH. Importantly, at the…

The continuing fascination of young people with celestial bodies leads them to pose challenging questions to their science teachers, such as how was the universe born? How were the stars formed? In this paper we present an extremely inexpensive but highly engaging activity to teach the basics of spectroscopy. Guided by the question "how do…

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…

The present article describes some activities performed with high-school students in the "Solar Physics" course developed in a Brazilian science centre. The topics of chemical composition, temperature and stellar evolution were taught in a room totally dedicated to study of the Sun, a solar room, designed with simple and inexpensive…

We present a laboratory practice aimed to clarify and discuss the concept of bioindicator molecules in environmental health. It has been implemented as a hands-on laboratory exercise in postgraduate courses in public health (in Brazil) and in a course entitled Biology Applied to Natural Resources Sustainability (in Spain) but can be useful for…