STEM Lab Random Generator Mechanical Model Kit

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UGears STEMLab kits are stylized educational models, They provide an interactive physical study guide to the mechanism, for discovering and learning its essentials and principles of working.

For generations, humanity has been futilely wrestling with perennial questions, such as whose turn is it to take out the trash? Who will vacuum today? And, of course, who does the dishes?

Those who volunteer to do all these chores have our eternal respect, but what if no one volunteers? The fair way to handle this would be to let chance decide and toss a coin. If you have ever bet on heads or tails, this means you got close and personal with probability theory and its practical application.

There is an alternative to the classic coin solution that is not only elegant and fun but has an extra educational benefit.

The Random Generator is a device that generates random numbers and provides different random results based on probability theory.

The main element of the Random Generator’s design is a cube with an octahedron inside it that, which contains a metal ball to provide weight. This construction is powered by a rack-and-gear drive initiated manually and providing energy through a driven gear that rotates a three-axle gear.

The vertices of the octahedron coincide with the sides of the cube. In this way as the energy of the system expires and it stops moving, gravity suspends the metal ball in the lowest part of the octahedron and due to the inclination of the walls it rolls within, it ends up in one of the octahedron’s vertices pulling in down. Whichever of the vertices turns up in the bottom, the side of the cube it is attached to will be right under it and parallel to the floor. In this way, the side of the cube with the answer will be the one facing up on the opposite side.

The probability to get any of the vertices facing down is virtually the same due to symmetry of the octahedron that rotates freely around the axis of its mass. This leads us to a simple conclusion that the probability to receive one of six answers is 1/6 or 0.167.

Every side of the cube positioned by the vertex of the octahedron, has a message: one says “YES”, the other “TRY AGAIN”, etc.   

The mechanism of the Random Generator is composed of:

  • Button
  • Rack-and-Gear Drive
  • Overrunning Clutch
  • Driven Wheel
  • Three-Axle Gear
  • Cube
  • Internal Octahedron
  • Weight

Model Size: 6.8 x 4.8 x 5.2 in
Number of parts: 160
Level: Easy
Assembly Time: 2 hours
Recommended Age: 8+