Rotators give us muscle and speed, the power to spin things at a useful rate in order to perform work or perhaps to just observe. We can stir a liquid, turn a fan blade, spin stroboscope discs or a color wheel.
Stroboscopes are very special when we need to know more about rotary or cyclical phenomena. They let us see and study high speed motions that we cannot easily observe by any other means. A stroboscope works by flashing an intense light of very short duration. If the rate of repetition is the same as the rate of the cyclical motion, each time the light flashes we will see a brief image of the object under study, but always at the same location. Its motion will appear stopped. If the flash rate is slightly higher or lower than synchronous, we can watch the object moving slowly through a complete cycle of its motion.
These two products go hand in hand as major tools to assist in the study of physics.