Intrigued Londoners looked on today as a smartphone’s battery was charged by a strange contraption made of 800 apples and potatoes connected with hundreds of nails and lengths of copper wire.
The art installation was created outside the Westfield Shopping Centre in Shepherd’s Bush, essentially just a large-scale version of the classroom science experiment where a single potato is used to power a digital clock.
By stringing 800 pieces of fruit and vegetables together with galvanized nails and wire, artist Caleb Charland was able to scale-up the power output so much that it could charge a mobile phone – in this case a Nokia Lumia 930, charged via a wireless mat.
The hand-built circuit created an electrical current of an average 20mA and around six volts.
How does it work?
The energy actually originates from the metal connecting the apples and potatoes, rather than the fruits and vegetables themselves. The zinc from the galvanized nails and copper act as electrodes, and the apple or potato acts as an electrolyte.
Atoms from the zinc electrode dissolve into the apple or potato as a positively-charged ion (an atom where the number of electrons is not equal to the number of protons), leaving two negatively-charged electrons stranded behind.
These electrons pass via the wire connecting the two electrodes in order to join with hydrogen ions from the apple or potato to form hydrogen gas. This flow of electrons is electrical current.
(Image Source: iCLIPART)