Why are white iPhones thicker than black ones?

Some technology-related websites are buzzing that the new white iPhone 4 is 0.2 millimeters thicker than the black model. (Don't believe me? Do a Google search on "0.2 millimeters.") Blogger Ryan Cash first noticed the difference when the white version of the phone came out in late April. He actually noticed that it felt thicker, so he measured both versions. Cash works in marketing for Marketcircle, a company that makes business apps for Mac, iPhone, and iPad. At first Apple tried to dismiss the story. Senior Vice President Phil Schiller tweeted: "It is not thicker, don't believe all the junk that you read." But the story wouldn't go away, so Apple finally tried to explain -- while emphasizing that 0.2 millimeters really doesn't make a difference, even to iPhone accessory manufacturers. Today PC Magazine takes a more in-depth look at the issue. Some of you are probably thinking, "it's because the white ones are painted." But PC Magazine points out that "a coat of paint is so thin, thinner than a human hair ... it wouldn't account for anything more than a couple of thousands of a millimeter." It turns out that the thickness issue is actually related to the plastic case. The white iPhone does have some design and engineering difference from the black model. But the bottom line is that there are small -- and apparently unintentional -- differences in the injection tooling used to mold the cases. PC Magazine calls the issue "Sizegate," but it's clearly tongue in cheek. Peter Pachal, the website's news director, writes that Apple must have been aware of the difference, but officials decided that because it had no practical effect, they didn't need to say anything. "Given that there haven't been any reports of people lining up to return cases they bought for their white iPhones, you could conclude (rightly) that a difference of 0.15 millimeters simply isn't a big deal after all," he writes. "'Sizegate' certainly isn't on par with the iPhone 4's antenna problems that plagued the phone upon its initial release. But for anyone who's ever looked at a spec sheet as definitive, it's a reminder that every number cited is really just an average, and your mileage may vary. Sometimes a lot," Pachal said. Maybe a molder making a case for a high-end product like the iPhone doesn't have to worry too much about a few extra grams of plastic. But I doubt it.