(access to video - probably only suitable if you have Broadband or a great deal of patience!)
Energy & Forces - Part 3 - Jan (video 14 Mb) - Which vehicle goes the furthest?

1. This will be new vocabulary for the children.

Kinetic Energy - This is the energy of motion. Things have kinetic energy when they are moving.

Potential energy - This is ‘held back’ energy like the energy in a spring which has been wound up but not allowed to work anything yet.

To understand this, think of a wind-up toy. When you wind up the toy you use kinetic energy (motion from your hand) to wind the spring. The spring holds that energy as potential energy (it stores it up) which is only turned back to kinetic energy when the toy is released to run.