Communities:Journal of Chemical Education
From ChemEd Collaborative
The Journal of Chemical Education provides a wealth of peer-reviewed information in the field of chemical education. Its community of readers, users, contributors, reviewers, feature editors, and staff forms one of the world's largest communities of individuals interested in the teaching and learning of the chemical sciences.
Provide Examples of Using the Web to Enhance Critical Thinking
Have you given your students assignments that involve viewing Web sites with a critical eye and applying scientific thinking to evaluate the claims made? If so, please join in describing your assignment and how well it worked with other members of the JCE community. you can join this wiki and enter your contributions below.
Magnetized Water: Science or Fraud? This article published in the October, 2008 issue of the JCE, describes student laboratory studies that determine whether water can be softened by applying magnets to the outside of copper pipes (Lahuerta Zamora, L.; Anton-Fos, G. M.; Aleman Lopez, P. A.; Martin Algarra, R. V. J. Chem. Educ. 2008, 85, 1416.). (A Google search for “magnet water soften” yields about 369,000 hits. Most sites on the first Google page claim that magnets soften water and then offer to sell you a kit to install in your home.) This article provides an excellent way for students to learn how to apply scientific investigation to an issue they might be wondering about as a result of their forages through the Web. The article (and an accompanying experimental procedure)describes how students can measure pH, conductivity, total hardness, and surface tension before and after the water is treated for different times in a copper pipe witih a magnetic device affixed to the outside of the pipe. Students can measure for themselves whether any change in the water occurs.
Run Your Car on Water. Did you know that there is a different form of water, HHO? A Google search for HHO yields about 5,860,000 hits (a search for H2O yielded about 32,800,000). Some of the Web sites describe oxyhydrogen mixtures used in welding, where the HHO describes the ratio, 2 H2 to 1 O2, of the gases fed to the torch. Most are for sites such as “Run Your Car on Water” [1], which make exaggerated claims for increased fuel economy by adding a water electrolyzer powered by the battery/alternator and piping the hydrogen-oxygen mixture to the engine’s air intake. These sites raise a lot of questions. For example, students could be asked to apply the first two laws of thermodynamics to using the battery (which is charged by the engine) to generate the fuel to run the engine. More advanced questions also arise: Could the hydrogen-oxygen mixture enhance octane; would that matter? Why do so many people who have installed electrolyzers say that their fuel economy improves; can so much empirical observation be wrong? Could the hydrogen-oxygen mixture catalyze combustion of fuel? Is it ethical to set up a Web site that purports to debunk claims of running a car on water, but in fact directs users to the “top three” sites that advocate for (and sell) electrolyzers? How many of the Web sites and testimonials supporting HHO for cars are created by the people selling electrolyzers?
Chemical Safety. Suggest that your students take a look at [[2]]. They will find lots of interesting information about the elements and probably will be intrigued by the videos for each element. Also ask them to watch critically for instances (such as the sodium-water explosion that results in a piece of sodium on the video camera--thank goodness not on the cameraperson) where they think chemical safety practices could be improved.
