I have emphasized the importance of AIs being able to act in/on the world. (For example in my blog of 23 March 2015) They need to be able to experiment as well as observe.
If one simply observes the operation of a Jacob's ladder two alternative theories of operation come to mind. Hot air rising between the electrodes may be lifting the arc or, alternatively, a Lorentz force may exist due to the current carried through the arc and the magnetic field produced by the arc and electrode loop. The Lorentz force would then propel the arc upward.
As an experimenter one can simply tip the apparatus on its side and see that the arc no longer travels alone the electrodes, the hot air explanation is the better one. The agent/experimenter's ability to act on the system being studied is quite helpful.