https://youtu.be/JVWtLrmafSk

"Hopper" is a 3D printed hopping mechanism. Using two springs and a "mass" (the battery, motor, motor holder, switch, gears, axle and cams), the mechanism first compresses the springs then releases them to propel the mass upward to an abrupt stop causing Hopper to hop.

Modeled after windup and battery powered hopping toys from my much, much earlier years, Hopper was designed to demonstrate the difference between potential energy (energy stored in the springs via the battery, motor, motor holder, switch, gears, axle and cams) and kinetic energy (energy released from the springs and the resulting velocity of the battery, motor, motor holder, switch, gears, axle and cams), while entertaining the grandkids as well!