A Simple Experiment To Measure the Content of Oxygen in the Air Using Heated Steel Wool

Abstract

The typical experiment to measure the oxygen content in the atmosphere uses the rusting of steel wool inside a closed volume of air. Two key aspects of this experiment that make possible a successful measurement of the content of oxygen in the air are the use of a closed atmosphere and the use of a chemical reaction that involves the oxidation of a solid element into a solid oxide. The oxygen for the chemical reaction is provided by the closed volume of air, whose volume changes are easy to measure. In previous versions of the steel wool experiment, several days were needed to complete it; however, the experiment can be completed in about 30 min by cleaning the steel wool using acetone and then washing it in acetic acid or vinegar. A new simple closed-volume experiment to measure the oxygen content in the air is described that can be completed in a few minutes. In this experiment, steel wool is placed inside a glass tube that is connected with two normal glass syringes. The tube is then heated by a flame and the air in the syringes is forced, by moving the syringes plungers, to pass through the heated steel wool. This experiment is an excellent classroom illustration of the 21% of O2 in the atmosphere, and it can be used as a complement to the steel wool–acetic acid experiment.

Technologies for Decentralized Fluoride Removal: Testing Metallic Iron-based Filters

“…Table 5 shows clearly that from the six most recent studies using SW, just one of seven possible previous peer-reviewed articles is referenced in two of six articles. This evidences the fact that SW is just qualitatively used as a Fe 0 -based material as it this been the case in classroom demonstrations of the oxygen content of air (approximately one-fifth of the dry air) for several decades [142][143][144][145]. For example, Birk et al [142] allowed acid-washed steel wool to rust in an air-filled container inverted in water; the decrease of air volume is measured.…”

Algunas consideraciones y propuestas en torno a la determinación del contenido en oxígeno del aire usando lana de acero

“…Por este motivo, antes de realizar el experimento debe lavarse con agua jabonosa o acetona. Para aumentar todavía más la rapidez con que la lana de acero reacciona con el oxígeno atmosférico, algunos autores han propuesto modificaciones consistentes en elevar la temperatura de la lana de acero, con ayuda de un mechero, [10] o en aplicarle un tratamiento que acelere su oxidación, tal como el uso de ácido acético concentrado. [6] A pesar de que ambos métodos reducen notablemente la duración del experimento, los riesgos que entraña el uso del mechero o el ácido acético concentrado limitan su aplicación didáctica, especialmente, en el ámbito no universitario.…”

“…El gran referente en este campo es George Pólya, un matemático húngaro, [9] aunque contribuciones muy importantes son debidas a Alexandru T. Balaban. [10] En este escenario tan general, podemos concluir que es tarea de los químicos teóricos predecir las propiedades de las moléculas desconocidas, de tal manera que se sinteticen aquellas que tengan las propiedades deseadas, de modo que el factor limitante no será la capacidad de síntesis (mil por segundo) sino la capacidad de cálculo (¿millones por segundo? ).…”

Steel Wool for Water Treatment: Intrinsic Reactivity and Defluoridation Efficiency

“…In particular, each visually thin strand of SW is made of thousands of metal fibres that are very reactive [15,16]. The rapid kinetics of SW corrosion justifies its use in scholar practical demonstrations [17][18][19][20].…”