February 8, 2006
Make a top spin for 30 seconds using a top spinner made with a compound gear train.
Use the Motorized Simple machine sets.
This gear train works as well as a gear on the motor.
This explanation was wonderful
about how the large 40 tooth gear drove the 8 tooth gear that was on the same axle as another 40 tooth gear
that drove the 8 tooth gear on the top.
