Google CEO Eric Schmidt has finally made it clear what differentiates Google’s Android OS from the soon-to-be-released Chrome OS: keyboards.

That’s a rather simplified expression of the bigger picture; but ultimately, Google () sees Chrome OS as the operating system for traditional computers, such as PCs, netbooks and laptops, which may include touch interfaces but always include keyboards; and the company sees Android () as an operating system best suited to mobile devices, which may include keyboards but almost always include touch interfaces.

During his talk at Web 2.0 Summit, Schmidt was asked by a member of the audience about Android’s perceived fragmentation. In addition, Schmidt was asked about where Chrome OS should be used vs. Android and where they overlap. The audience member professed that he was confused about Google’s strategy surrounding both platforms.

Schmidt responded in a few parts. His first point was that Android isn’t fragmented, stating that you can still run the same app on all Android phones — a point which our readers are welcome to dispute in the comments. However, Schmidt emphasized that he wants to make sure you can run the same apps on all Android devices.

What I found more interesting was his response to the difference between Chrome OS and Android. He iterated multiple times that it seems like Android is optimal for touch devices, while Chrome OS is best suited for traditional keyboard devices. While this explanation makes perfect sense to us, we’ve never heard this explanation from Google’s CEO until now.

In other words, if Google builds a touch-based tablet, it’s going to run Android. If it builds a new type of keyboard computer device, it’ll run Chrome OS. Schmidt says to expect Chrome OS “in the next few months” and the new version of Android (a.k.a. Gingerbread) in the next few weeks.