News Physics

Squishy materials reveal new physics of static electricity 

How objects charge when touched depends on their history, scientists find 

A girl closes her eyes as her long brown hair clings to a yellow balloon touching the top of her head.

A balloon rubbed on hair will pick up a negative charge, but scientists still don’t understand exactly how this process works.

Yuricazac/Istock/Getty Images Plus

By Emily Conover

Rub a balloon on your hair and the balloon typically picks up a negative electric charge, while your hair goes positive. But a new study shows that the charge an object picks up can depend on its history. The number of times an object had previously touched another determined whether the object became negatively or positively charged when touched again, researchers report in the Feb.