One recurrent theme in The Simpsons is the presentation of boring tutorial films to elementary school children. For those of you who think that advertising targeted to schoolchildren is a recent phenomenon, students of my generation sat through many sports tutorials containing an embedded ad for Wheaties cereal. One film presented to Bart Simpson's class was "A World Without Zinc," that depicted what life would be like without the metal, zinc. The film's teen protagonist cries, "Come back, zinc, come back!" when he realizes how much of modern life depends on this metal. Actually, biological life as we know it would be impossible without zinc, as stated on The Periodic Table of Videos.[5] A cellphone camera capture of "A World Without Zinc" is available via YouTube, here. Zinc was an important metal of my own childhood. I enjoyed the Metal Men comic books, the characters of which were robots with qualities that matched their element; e.g., iron was a strongman, and platinum was a platinum blond woman. Zinc appeared in Metal Men, vol. 31, May, 1968, pp. 2,6. Perhaps these comics were my inspiration to pursue metallurgy/materials science. Also a part of my childhood, in the days before ubiquitous injection-molded plastic toys, were toys made from die cast zinc. Zinc is an excellent material for die casting. It's a relatively benign metal with a low melting point (419.5 °C). Not-so-benign mercury, gallium, lead, bismuth and cadmium, among others, have lower melting points. Zinc is used less frequently than only three other metals, iron, aluminum and copper. It's also inexpensive, being currently about one US dollar per pound.[6]
Hubley Realtoys 1958 Ford police vehicle, made from painted, die-cast zinc. (Photo by C. Steven Campbell, via Wikimedia Commons). |
Fe -> Fe2+ + 2e-The downside is that the sacrificial anode is corroded, instead, but there's a net advantage to the lifetime of the steel structure. Many years ago, my family discovered zinc throat lozenges as a common cold remedy. This patented [7] delivery mechanism for the active ingredient, zinc gluconate, has been shown in one clinical study to markedly reduce cold symptoms. Coughing and cold duration were essentially cut in half.[8] One tip, as advised by the manufacturer, is not to use these on an empty stomach, or you might be moaning, "Why, zinc, why!"
EX ZINCO, MULTO US Lincoln pennies dated 1983 or later are copper-plated zinc (97.5% Zn, 2.5% Cu). Earlier coins, except 1943, which were zinc-plated steel, are 95% copper. (Via Wikimedia Commons). |