The Pelton wheel (Fig. 48), a modified form of undershot wheel, has cup-shaped buckets sticking outward at regular intervals around its circumference. There is a partition in the center of each bucket. A nozzle is so arranged that it directs water on the buckets as they reach the lowest point of a revolution. The water strikes the partition of the cup and turns right and left inside of the cup. The change of direction transfers the energy to the wheel.