Although many of the devices we use daily have moved on from disposable batteries to rechargeable ones, we still need regular batteries of all shapes and sizes for a variety of electronics – including remote controls for our TVs, some gaming controllers, and even watches and clocks.
It’s not uncommon for a household to have a bag full of random batteries, and if you have one of these in a drawer, there’s probably one big problem – you have no idea which batteries still have some juice in them and which are dead.
Even when it comes to changing the batteries in your remote control, it can be hard to know which of the two or more batteries caused the remote to stop working or if all of them need changing.
Some batteries come with a visible level to help you gauge how much juice they’ve got left, but that isn’t the case for all batteries, so working out which ones you need to throw away can be a nightmare.
But according to an expert on TikTok, there’s an « easy trick » to knowing whether your batteries have reached the end of their life cycle – and you just have to drop them on the floor.
Jordan Cox shared a video on TikTok in which he said the easiest way to tell if a battery has juice is to hold it about six inches from a hard and flat surface, like the floor or a table, and drop it.
When it hits the table, it will either bounce or immediately fall flat – and this is how you know whether it’s dead.
He said: « If it does bounce, it’s completely dead. But if it just falls over, there’s still more life in there to be used. »
Researchers at Princeton University previously tested this theory. They found that while it can give some decent results, it isn’t a foolproof way to determine whether batteries are out of juice.
Instead, the test actually tells you whether the battery is fresh or whether it’s old. But old batteries can still have plenty of juice in, so it isn’t a hugely reliable test for the effectiveness of your batteries.
Daniel Steingart, an assistant professor of mechanical and aerospace engineering and the Andlinger Centre for Energy and the Environment, said after the test in 2015: « The bounce does not tell you whether the battery is dead or not, it just tells you whether the battery is fresh. »
The researchers also found that the bounce test works because of the way batteries produce power. Electricity is generated by a chemical reaction inside the batteries as zinc changes to zinc oxide. The more zinc oxide that’s inside the battery, the bouncier it becomes.
Steingart added: « The zinc oxide begins to form on the outside, and it pushes its way to the core. As you get more and more zinc oxide, and the zinc oxide begins to appear everywhere in the zinc layer, the battery gets bouncier and bouncier. »
However, batteries reach peak « bounce level » before the oxidation of zinc is complete, so the bounciness of your battery will peak and level off well before the battery is dead – meaning a bouncy battery isn’t always a dead one.
The test can definitely tell you if a battery hasn’t been used at all, but if you rely too heavily on it, you may end up throwing away some batteries that still work.
