We’ve gotten more mileage out of this simple lab than anything else we’ve ever done! We must admit it is easy and fast — with no disposal issues. We basically are separating water from a colored solution by boiling and collecting the water on a cold finger — created with inexpensive aluminum foil filled with ice.
In Canada, one challenge is to excite indigenous peoples about science, and chemistry in particular. For many years, with a series of student colleagues, we have been taking a Chemistry Show to schools in remote communities in western and central Newfoundland, coastal Québec, Labrador and even Nunavut (see References).
In August 2015, Educational Innovations was able to bring back goldenrod paper. For years, this paper had been discontinued, apparently because goldenrod paper was not able to be recycled. The fibers in the paper were saturated with golden colored dye.
The Chemical sunset demonstrates the Tyndall effect in a fun and engaging way. We have used this demonstration for both instructional and outreach purposes. Colloidal sulfur is produced by the reaction between sodium thiosulfate and hydrochloric acid.
Part 1 of this article was published in Chem 13 News in November 2014. This second part presents three titration exercises of increasing sophistication, suitable for students with some titration experience. Citric acid and sodium hydroxide are used for all three presented titrations.
The determination of the limiting and excess reagents in a chemical reaction tends to be a challenge for many chemistry students. Teachers have used the making of cookies and hamburgers, or combinations of nuts and bolts, among other common items to help students understand these concepts. While students understand that if you have 10 hamburger patties and only 6 pickles one can only make 3 hamburgers, if each requires 2 pickles.
We know that acids dissolve our pearly whites, but where does this acid come from and what chemistry is really going on in our mouths to make this happen? If your mouth hosts biofilms of certain bacteria, especially Streptococcus mutans that are feeding off sugars, the teeth will be in contact with acid.
Penney Sconzo presented this nifty demonstration at the ChemEd 2015 Generations Symposium in Kennesaw State University, Kennesaw GA. This is an easy, colorful and safe microscale version of the Ammonia Fountain.
This last article of a three-part series describes how to use syringes, pressure gauges and Mason jars to do the gas laws: Boyle’s Law (pV), Gay-Lussac’s Law (pT) and Avogadro’s Experiment (pn). The huge advantage of using a Mason jar for the pressure vs amount relationship is that the stopper and ring combination produce a sealed container that can withstand a pressure inside of 2 atm without fear of the stopper popping or the glass breaking.
For years I believed that solid iodine, I2, only underwent sublimation when heated at atmospheric pressure. I was so wedded to this idea that I performed the demonstration for years.