{Just an interesting tidbit of information}
Today in chemistry class we put on our goggles and aprons and turned pennies into gold. Well, not really gold, but first a silver alloy and then a gold alloy.(if it were really gold or silver we'd all be home washing pennies) It is a relativelty simple process, found below
" A penny is boiled in a solution of NaOH[sodium hydroxide] together with some granular zinc metal, the color of the penny will turn silver in about 45 seconds. The penny is then held in the flame of a burner for a few seconds and it turns golden. The reason this happens is that granular zinc dissolves in NaOH to form Zn(OH)42-. This zincate ion becomes reduced to metallic zinc on the surface of a copper penny. Zinc and copper when heated in a flame form brass."
http://en.wikipedia.org/wiki/Sodium_hydroxide#Experiment
Though we used hot plates,it turns out that an open burner gives an even gold coat to the pennies. The hot plates burned many pennies, and turned the zinc solution into a thick white gunk. To make the penny a better shade of gold, simply return the penny to the solution, allow it to turn silver and then heat it again. Too many pennies in the solution mean that there will be less chance of an even coating, and less chance of you fining the penny you began with.
Pennies minted after 1982 will work the best in this expieriment due to the fact that the U.S. mint began making pennies with 95% zinc coated with 5% copper. Also, the prettiest penny is your best bet for a perfect coin. Any gunk on or around the penny will simply burn to a black spot onto the penny, allowing the penny to turn back to its original color.
It is suggested that you do this expiriment in an equipped lab with supervision,and full scientific protection (goggles etc.), working with small boiling pennies can cause serious injury.
