Colors project well in petri dishes on an overhead projector. An analog meter with a 30-cm scale is connected through an amplifier to a pH meter and a glass electrode. The same large meter can be used as a voltmeter for electrochemistry and as a thermometer for thermochemistry demonstrations. The two voltmeter demos offered are potential differences between Zn, Cu and Pb, and using bologna as a salt bridge. Endo- and Exothermic Reactions Procedure Hot and cold packs are passed around the class.
Students can note the temperature change.
Last about 15 minutes. The Classic Belousov-Zhabotinsky Oscillating Reaction Procedure Equal volumes of prepared solutions, mixed on a stir plate with ferroin indicator, give a solution that oscillates from green to violet to red to blue and back to green. Lasts about 30 minutes. A Variation of the Belousov-Zhabotinsky Oscillating Reaction Procedure Three premeasured solutions are mixed, stirred until the bromine color disappears, and ferroin indicator is added. Oscillations will start.