Abstract: Thin films, like soap bubbles and oil slicks, owe their pretty colors to the process of thin film interference. Anodized Titanium, Scandium, Niobium, and Tantalum also exhibit lovely coloration due to thin film interference associated with the oxide film anodizing creates. These are so lovely, in fact, that they are sometimes used to make jewelry! In this activity, each team of students will observe a sampling of thin films. They will then anodize a small sample of titanium to observe the nature of the electrochemical reaction (anodizing), TiO2 thin film interference, and the relationship between the thickness of the TiO2 film formed and the color seen on the metal. Future modules are planned for this experiment, which will add specific quantitative examination of the thin films observed here.