Grand prize winner: Turn your pennies into ‘gold’
Rosemarie Pittenger, a science teacher at John P. Stevens High School in Edison, N.J., made the most of her pennies with this demonstration of metallurgy and surface science. To make the silver-looking pennies, Pittenger placed coins in a bath of 1 M zinc chloride solution with small lumps of zinc. Zinc ions in the solution were reduced by the copper on the penny’s surface, producing zinc metal that plated the penny with a thin, silverlike coating. To make the golden penny, Pittenger put one of the zinc-coated coins on a hot plate for a minute or so. The heat made the zinc coating and remaining copper underneath diffuse into each other and mix to form the alloy yellow brass.—Manny MoroneSubmitted by Rosemarie Pittenger. Pittenger will win a hot plate, glassware, and an electronic balance.
Credit: Rosemarie Pittenger