how does a pogo stick work.?

[EvilMonkeyin]

Okay, I know it's a toy you get on and jump up and down on but what is the science of how it works(physics)?

[woofgang]

its the same science as anything else where you store energy by compressing a spring

[Octavius]

A traditional pogo stick's jumping power comes from a steel spring inside its body. When you jump onto the pogo's pedals, the force (push or pull) of your weight pushes the body of the pogo stick toward the ground. That stretches a metal spring that's attached to both the top of the stick and the foot pegs. As the spring's coils elongate, the pogo gains elastic potential energy, stored energy due to being stretched or compressed. When the coils are stretched to their max, your knees pull up. Then, BOING! The spring quickly returns to its original length. All of that stored energy is released to the rest of the pogo stick in the form of work (transfer of energy). The result: The rider bounces off the ground.

Because steel is not very elastic (stretchy), a large spring is needed to pack high-flying energy. The trade off: Steel is heavy. And the extra weight keeps large-spring pogo sticks closer to the ground.

The rest is gravity.

[Clanad]

Octavius may well be right, but having taken one apart as a child (bad idea!) I found the spring to be under compression for energy storage.  That is, the spring compressed on the down stroke, rather than stretching out, to provide the bounce reaction.  Manufacturers probably have differing ways of producing the "jump".

[jade_pie]

the spring actually oscillates! search on the internet for the physics k x