Âé¶¹´«Ã½

Physics

When opposite charges repel

16 September 2009

Video: Charged water droplet

Âé¶¹´«Ã½. Science news and long reads from expert journalists, covering developments in science, technology, health and the environment on the website and the magazine.

Opposites repel

(Image: PBNJ/Getty)

OPPOSITES always attract, right? Not quite. A new experiment has shown that a drop of water with positive electrical charge can be made to “bounce off” a negatively charged object.

of the University of California at Davis accidentally applied a strong electric field to a beaker filled with oil and water. At first the mixture erupted into a turbulent mess, but as he turned down the voltage Ristenpart saw droplets of water suspended in the oil bouncing between the electrode at the top of the beaker and the oil-water…

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