Many of us use gadgets that sport gleamingly refined, anodized aluminum or titanium cases -- but have you ever wondered exactly how the process works? Bill Hammack, at it again after explaining to us how the CCD, LCDs, and hard drives work, breaks it down (pun intended) for us -- in less than five minutes. He talks about, and even shows us how the surface of titanium is meticulously rusted using electro-chemicals to grow an oxide layer, changing the color based on its thickness. He follows that up with some commentary on how a similar reaction gobbles up and transforms aluminum, creating a much thicker, porous oxide layer that can be filled with any color dye. So, just to be clear: controlled corrosion is good for your Mac, border control -- maybe not so much. You can watch the video right after the break.