Iron-Coated Polystyrene Spheres

Iron is the most common element on earth, and the sixth most abundant in the known universe. These slightly rusty iron balls are intriguing, they are surprisingly light as they are hollow, but bear no seam-lines or clues as to how they are made. They are actually formed by electroplating – iron-plating a small sphere, perhaps polystyrene, which is then burned away so that only the hollow metal remains.

Metal electroplating is a process more commonly applied to other metals as the object needs to conduct electricity - plastics and other nonconductive materials need to be prepared with a special coating - a process sometimes used for dental bridges or circuit board parts. The coated polystyrene ball would be attached to the negative charge of a battery, and immersed in a water bath containing iron salts. Another positive electrode is then introduced to the liquid, causing the ions (negatively charges atoms or molecules) of the iron to coat the surface of the polystyrene ball.