A model which demonstrates the 1st Class Lever.
The small person is fixed to the Teeter Totter while the large person can be placed on
either of the protruding 3/8” Bolts. When placed upon the inner bolt it will be found that
the effort arm of the lever (the distance from the fulcrum to the effort) is not long enough.
Hence the Teeter Totter tips the small person downward. If the larger person is placed on
the outer bolt then the effort arm is increased and the Teeter Totter lifts the small person