Contrary to popular belief, the first cell by Volta was not the zinc and copper plates dipped in acid, as can be seen in the photo in the Como museum.

Following in the steps of Galvani, Volta understood that electricity is present in muscles. In 1798 Volta observed that if he placed pieces of silver and zinc on his tongue (silver a little further, and copper just on the tip of the tongue) he felt an acid-like taste. If you swap the order of metals you feel an alkaline taste.

You can repeat this experiment easily. Take a paper clip and put a coin into it. Put out your tongue as far as you can and place the clip with the coin on your tongue. Don' swallow the clip and don't bite off your tongue. Or you can as well lick a metal pencil sharpener since it is very difficult to come across a real silver or zinc coin.

The "voltage" (see the lemon battery) is also the cause of the acidic taste of the metal pencil sharpener. Even if your saliva is used as the electrolyte (a wet piece of paper), the voltaic potential as high as 1.1 V can be generated between the aluminium body and the steel blade.

Volta's piles are everywhere - in cars, cell telephones, computers. Depending on to their application, they have to be durable and resistant (in cars), light (in cell phones) or long-lived (in computers). All these properties can be obtained by a proper choice of the electrolyte and electrodes.

The most popular is still the zinc-carbon battery. Unfortunately, if left for a long time, it undergoes corrosion and can spill-out and damage the appliance.