Speed Spinner

Explanation of the Speed Spinner:

• Age range and child interaction:
  • The target age group for the speed spinner is more or less grade school and middle school aged children. With this in mind, it would be safe to assume that children anywhere from 5-12 years old, give or take a few years, would be playing with this toy.
  • The speed spinner is merely a complex version of the classic playground merry go round. It will be played with in much the same way as its classic counterpart, with a group of children strapped in their seats while one or several of their playmates pushes the toy round and round. The only real addition comes in the form of a handle near the child's seat that can be pushed back and forth to change the radius of rotation for the toy -- more on this later.
• Scientific principle behind the toy:
  • The main concept behind the speed spinner is conservation of angular momentum, which stems from basic Newtonian mechanics (F = ma). For a spinning object, its angular momentum (L) depends on mass (m), velocity (v), and spinning radius (r) relative to its axis of rotation. Put simply, L = mvr. While the principle of conservation of momentum is a reality, there can also be energy losses involved such as friction. The efforts of science today help overcome most of these effects, like the use of precision bearings in rotating parts. The speed spinner would most definitely utilize these types of efficient components to help make the reality of the toy as close to the scientific theory as possible.
  • For the speed spinner, as one of the riders pulls the handle inward, each of the seats would move toward the center of the toy, effectively reducing the spinning radius. Assuming the rotating mass remains constant -- which hopefully is the case, provided no children go flying out of their seats in the middle of the ride -- there must be an increase in rotational velocity to conserve the toy's angular momentum in order to account for the decrease in spinning radius. In simple terms, if any of the riders pulls the handle inward (r ↓), the toy spins faster (v↑), whereas if they push it away from their body (r ↑), the toy slows down (v ↓). Playing with the speed spinner could possibly help children begin to understand basic scientific principles such as conservation of angular momentum, also providing loads of fun for everyone involved.
• Construction cost, durability and safety:
  • A standard steel model of a six foot diameter playground merry go round currently sells for around $3,000.00. Because of the increased complexity, multiple material types, and more need for safety precautions for the speed spinner, it would be safe to say that the construction price would be of similar magnitude, but likely higher. A first prototype could easily be several thousand dollars more than the standard version, depending on size, quality and several other factors. If mass production was planned, a great deal of manufacturing engineering could be applied to the design in order to drive the construction and sale price down.
  • Any composite plastic components of the speed spinner, such as the seats, should easily withstand many years of weathering and use. The steel and other metal components, if painted or coated appropriately, could also last a very long time. Also, if moving components are lubricated correctly and regular maintenance occurs, the wear on the toys critical components should be minimal. With these things in mind, it wouldn't be a stretch to think that a speed spinner could last 10, 20, maybe even 30 years.
  • Safety would definitely be the number one concern during design. Riders would definitely need to be restrained somehow, moving parts would need to be covered, all connections should be smooth to avoid cuts, etc., and some sort of speed controller would need to be employed. Although this is not a complete list of safety issues, it does begin to touch on some of the major considerations that need to be made. In the end though, there is a certain amount of unavoidable danger present when you have a massive object spinning -- that's energy for you -- so the engineering involved must look to minimize the risks to avoid any playground bumps and bruises.