This article describes how to construct two simple, inexpensive, and illustrative apparatuses using disposable polyethene pipets and floral wire for electrolysis of water. These apparatuses suit various grades and curricula.
The galvanic cell presented in this article is made of only three parts, is easy to assemble, and can light a red light emitting diode (LED). The three cell components consist of a piece of paper with copper sulfate, a piece of paper with sodium sulfate, and a piece of magnesium ribbon. Within less than 1 h, students have time to discuss the function of the main battery parts, construct the cell, and test it with a LED. This low cost laboratory activity is suited to most general chemistry curricula.
The decomposition of water by electricity, and the voltaic pile as a means of generating electricity, have both held an iconic status in the history of science as well as in the history of science teaching. These experiments featured in chemistry and physics textbooks, as well as in classroom teaching, throughout the nineteenth and twentieth centuries. This paper deals with our experiences in restaging the decomposition of water as part of a history of science course at the Norwegian University of Science and Technology, Trondheim, Norway. For the experiment we used an apparatus from our historical teaching collection and built a replica of a voltaic pile. We also traced the uses and meanings of decomposition of water within science and science teaching in schools and higher education in local institutions. Building the pile, and carrying out the experiments, held a few surprises that we did not anticipate through our study of written sources. The exercise gave us valuable insight into the nature of the devices and the experiment, and our students appreciated an experience of a different kind in a history of science course.
This demonstration describes how normal and reverse phase chromatography can be illustrated using only chromatography paper for the separation of extracts of dandelions.
A chemistry concept inventory (Chemical Concept Inventory 3.0/CCI 3.0) has been developed for assessing students learning and identifying the alternative conceptions that students may have in general chemistry. The conceptions in question are assumed to be mainly learned in school and to a less degree in student's daily life. The inventory presented here aims at functioning as a tool for adjusting teaching practices in chemistry and is mainly designed for assessing the learning outcome during university general chemistry courses. Used as a pre-test the inventory may also give information about student's starting point when entering university's first year chemistry courses.The inventory also aims at functioning as a tool for adjusting teaching practices in chemistry. It has been administered as a pre-and post-test in general chemistry courses at the Norwegian University of Science and Technology (NTNU), and evaluated using different statistical tests, focusing both on item analysis and the on the entire test. The results indicate that the concept inventory is a reliable and discriminating tool in the present context.
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