penny of gold

Yesterday in chemistry class we turned a penny to glod...not real gold. I took a ditrt, ugly looking penny and i turned it shiny. First we put the penny in zinc...not sure what it is, and it turned it silver, but i think it just coated it so that the color will change to gold. After we took the penny out of the zinc we put the penny over the fire and it turned gold after a few seconds and yayayaya it is cool.