An experiment on the Rayleigh instability of charged liquid drops

We describe a simple experiment to observe the fission of an electrically charged liquid droplet. Rayleigh charge instability occurs when the electrostatic repulsion of charges on the surface of a droplet overcomes the droplet surface tension and tears the droplet apart. The experiment requires a low-power laser, simple optics, a CCD camera, and a quadrupole trap, which can be constructed using widely available and relatively straightforward instructions. The experiment was performed primarily by undergraduates as part of their senior research projects and can be implemented readily in an advanced undergraduate physics laboratory course.