Ever spent ages swapping batteries in and out of remote controls to find out which ones still have power in them?
Next time, just try dropping them on a hard surface and see if they bounce.
This is because spent alkaline batteries are more likely to bounce than fresh ones, according to an American electrical engineer whose video demonstrating the phenomenon is becoming an internet sensation.
To test outgassing, Mr Hite dropped a weight on the battery. If there was a build up of pressure, a weight should bounce higher on one than the other. He also drilled holes in the batteries to release this pressure. There was not a 'convincing' difference in the first test, and the bad battery still bounced in the second
In his YouTube video, Lee Hite tests a series of batteries that have expired against a set which have not been used.
He demonstrates that a used battery bounces far higher than one that has only just been taken out of the packet.
A good battery, he explains, contains a gel-like substance which solidifies as the battery discharges its electricity.
While the gel is in a semi-liquid form, it absorbs the energy when the battery hits the surface.
An anti-bounce hammer, which contains an internal core of moving buckshot, works in the same way.
When the gel in the battery has solidified it cannot move and the whole battery bounces, the same way that a solid hammer bounces off a nail.