Swinging Back and Forth

 From a young age, children are attracted to the magic of the swing - or should I say the physics of it. Although it is true that toddlers' forward motion is provided by their parents' pushing of the swing, older kids manage to increase the speed of their motion without any external force helping them. This is explained by the theory of the parametric oscillator. By raising his/her body at the lowest moment of motion and lowering themselves at the highest, the child manages to increase his/her momentum, thereby lengthening the arc traveled on each swing.