Limited Slip Gear Differential

I went to the new exploratorium in San Francisco where I saw a working model of the limited slip differential system used in cars.  I'm still learning about it, but I think the gearing mechanism is used to allow one wheel to move faster than the other to prevent skidding on a turn.  Basically, when one wheel has friction and slows down, the other wheel speeds up to compensate for the lack of energy.  Differentials are important because on a turn, when the outer wheel travels more distance then the inner one.  If they both rotate the same amount of times, then the outer wheel will be dragged, ruining the tire.
Here is my firs differential: