Differential facts for kids
Differentials can also be used in automobiles, where they are used for turning, for example, while turning right, the right wheel travels a shorter distance than the left, the differential slows down the wheel so it will not slip.
This is because the inside (right) wheel is closer to the center of the turn, meaning that it travels on an arc with a shorter radius, thus resulting in less distance traveled.
Differential Facts for Kids. Kiddle Encyclopedia.