Official Google Blog: Will it lens?
As cool as this is I challenge the statement that the this middle penny is brass. To heat enough to get that alloy you would first need to melt the zinc and then the penny would be much more deformed. Heated pennies go thorough a lot of color changing phases. The middle penny is the suspect one.
Friends if you are reading this please buy me one of these giant ones. I would love to try to do zinc casting powered by the sun.
I will make you a nice ring or belt buckle or something.
Casting a zinc belt buckle