The European Physical Journal Special Topics

, Volume 223, Issue 5, pp 959–977

The Armstrong experiment revisited

  • Elmar C. Fuchs
  • Adam D. Wexler
  • Astrid H. Paulitsch-Fuchs
  • Luewton L. F. Agostinho
  • Doekle Yntema
  • Jakob Woisetschläger
Review

DOI: 10.1140/epjst/e2013-01924-x

Cite this article as:
Fuchs, E.C., Wexler, A.D., Paulitsch-Fuchs, A.H. et al. Eur. Phys. J. Spec. Top. (2014) 223: 959. doi:10.1140/epjst/e2013-01924-x
Part of the following topical collections:
  1. Discussion and Debate: Water Complexity — More than a Myth?

Abstract

When a high-voltage direct-current is applied to two beakers filled with water or polar liquid dielectrica, a horizontal bridge forms between the two beakers. This experiment was first carried out by Lord Armstrong in 1893 and then forgotten until recently. Such bridges are stable by the action of electrohydrodynamic (EHD) forces caused by electric field gradients counteracting gravity. Due to these gradients a permanent pumping of liquid from one beaker into the other is observed. At macroscopic scale several of the properties of a horizontal water bridge can be explained by modern electrohydrodynamics, analyzing the motion of fluids in electric fields. Whereas on the molecular scale water can be described by quantum mechanics, there is a conceptual gap at mesoscopic scale which is bridged by a number of theories including quantum mechanical entanglement and coherent structures in water – theories that we discuss here. Much of the phenomenon is already understood, but even more can still be learned from it, since such “floating” liquid bridges resemble a small high voltage laboratory of their own: The physics of liquids in electric fields of some kV/cm can be studied, even long time experiments like neutron or light scattering are feasible since the bridge is in a steady-state equilibrium and can be kept stable for hours. It is also an electro-chemical reactor where compounds are transported through by the EHD flow, enabling the study of electrochemical reactions under potentials which are otherwise not easily accessible. Last but not least the bridge provides the experimental biologist with the opportunity to expose living organisms such as bacteria to electric fields without killing them, but with a significant influence on their behavior, and possibly, even on their genome.

Copyright information

© EDP Sciences and Springer 2013

Authors and Affiliations

  • Elmar C. Fuchs
    • 1
  • Adam D. Wexler
    • 1
  • Astrid H. Paulitsch-Fuchs
    • 1
  • Luewton L. F. Agostinho
    • 1
  • Doekle Yntema
    • 1
  • Jakob Woisetschläger
    • 1
    • 2
  1. 1.Wetsus — Centre of Excellence for Sustainable Water TechnologyLeeuwardenThe Netherlands
  2. 2.Experimental Turbomachinery Research and Optical Measurement Group, Institute for Thermal Turbomachinery and Machine DynamicsGraz University of TechnologyGrazAustria