My best friend’s son recently turned four-years-old and for his birthday his grandparents bought him a few toys. In addition to some extra pieces to accompany the train set he had gotten for Christmas, his grandmother and grandfather bought him a gear set. I have never seen anything quite like it; you have the option of using a rectangular or circular frame, and inside the frame you set up gears so they will interact with one another.
The gears themselves are made of plastic and they are a variety of bright colors. They are mostly in the style of spur gears, but when you use the gears in concert with the circular frame they form what closely resembles planetary gears. Planetary gears as so named because of their design. Just like a model of our solar system where the planets orbit around the sun, with planetary gears there is a central gear around which other gears revolve. Planetary gears are so closely related to a model of the solar system that the gear that rests in the center of the other gears is referred to as the sun gear.
In the case of this toy the planetary gears, according to the directions, are the best types of gears to build because children like to watch gears mesh together and turn one another. This is certainly true with my friend’s son. His gear set came equipped with a handle you can attach to certain gears that will act as the primary turning gear. This gear crank is his favorite feature because he gets to be the one to make the gears work. He is delighted by the toy because from start to finish because he gets to be the one to build the gears arrangements, attach the handle, and make them turn.