This is Scientific American 60 Second Science.

I'm Cynthia Graber.

Got a minute?

They're called Button Cells, Coin Cells,

or Watch batteries.

By any name, these tiny round batteries pose a choking danger to small kids.

And if a child succeeds in swallowing a button cell, the battery may short circuit in the moist esophageal environment burning the tissue.

A few thousand kids wind up in emergency room. o Prolific inventor Robert Langer thinks they have a partial solution, a protective

coding. The scientists covered batteries with a material, technically a quantum

tunneling composite in which micro particles of conductive metal are

suspended in an insulating layer.

Under most circumstances, including inside of a child, the layer is non-conductive.

But when the material is subjected to high pressure,

the micro particles are squeezed close enough together to carry a current.

One such pressurized environment is the typical battery compartment in a small device.

You often have to force the battery into place.

So the same battery that remains

inert when swallowed works just fine when it's jammed into its slot in a hearing aid.

The waterproof design would also protect batteries from corrosion and high

humidity.

The research is in the Proceedings of the National Academy of Sciences.

Tests with pigs found the coated batteries to be gentle on the poor sinusophagus.

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