When a sufficient electrical charge is applied the body of the polymer-solvent solution becomes charged. As the electrostatic forces overcome the surface tension a Taylor cone is formed. A thin cylindrical jet emanates from the droplet surface extending towards the direction of the electric field. Elongation along this axis continues until electrical bending instability occurs. Here the mode of current flow changes from ohmic to convective as the charge migrates to the surface of the fibre. This causes the jet to quickly bend through 90° leading into a series of loops under rapid acceleration. This ‘whipping’ process is responsible for nanometer scale reduction in fibre diameter.