Copper quarters – Using some long pliers, take a quarter and insert it into the flame. You’ll want to rotate it every few seconds to heat it evenly. After about 20 seconds it should be glowing red, to avoid overheating it, you’ll want to remove it at this point.
Immediately drop the quarter into a 100 ml (3.3 oz) beaker filled with roughly 60 ml (2 oz) of Heet. It will begin to boil vigorously and then slow down to almost nothing, only to start boiling again in one short burst.
Watching the process again. Watch how quickly the Heat boils; as its boiling point is only 148 degrees Fahrenheit (64 Celsius), where the coin we’re dropping in is over 1200 degrees Fahrenheit (648 celsius)! During the cooling process, some of the inner copper core of the coin has migrated to the outside, leaving you with a cool copper plated quarter! What’s going on?
There are two really cool principles. The first question you might have is why use Heet? Why not water? Well, what the Heet does, is it works like an oxidizer and with just water we’d just wind up with black coins. So that’s what the Heet does.
So the second effect we saw here is called the Leidenfrost effect and its very cool. Its what caused that double boiling that we saw. This is where the coin gets a very thin vapor layer around it that actually protects the Heat from the high heat of the coin. Until it collapses. It doesn’t last very long and then we get that second boil as it reconnects. Pretty awesome!