Many of us will have played with a pogo stick when we were younger, but what unique technology lends this toy its impressive bounce? The device consists of a cylindrical tube with footpads mounted on the bottom and handlebars on the top, with the tube containing a second cylinder attached to a large internal spring. Lastly, fixed to the bottom of the stick is a tough, rubberised foot contact.
When the user climbs onto the pogo stick – with their feet positioned on the pads and hands on the bars – a jumping motion causes the internal spring to become compressed, storing the generated kinetic energy. As such, rather than the energy dissipating into the ground – as would happen if the person was jumping without a stick – what follows is the decompression of the spring, which propels the device up in a sudden release of energy.
As a portion of this energy remains within the spring after the first decompression, upon making contact with the ground again this energy is added to the second jump. As a result the bouncer gets higher each time until a plateau is reached where forces balance out.
Traditionally pogo sticks were created as children’s toys, with low-power springs offering only modest jumps. Today, however, there are also high-power versions that allow a variety of tricks and stunts to be performed by extreme sports enthusiasts.