Watch: Simple bounce test tells you how much charge is left in your battery

Have you seen the viral YouTube video that shows how you can test a battery, whether it's new or old? Bounce it, and the older the battery is the higher it will bounce. Explaining the phenomena scientifically, experts say that an alkaline battery consists of a gel zinc anode and an MnO2 cathode. When the battery discharges, the zinc anode begins to oxidise, forming Zn(OH)42 ions in solution until the electrolyte is supersaturated.

The ions then precipitate into ZnO around the zinc particles and create a percolation network throughout the anode, densifying the gel into a solid ceramic at approximately 50 per cent charge. This change significantly increases bounce height at a rate that directly relates to the formation of ZnO. After the ZnO ceramic is fully formed, when the battery charge decreases to half, the coefficient of restitution will stabilise and the battery bounce stays the same.