Potato battery
PARTS AND MATERIALS
The basic experiment is based on the use of
a potato, but many fruits and vegetables work as potential
batteries!
For the zinc electrode, a large galvanized
nail works well. Nails with a thick, rough zinc texture are
preferable to galvanized nails that are smooth.
CROSS-REFERENCES
Lessons In Electric Circuits, Volume
1, chapter 11: "Batteries and Power Systems"
LEARNING OBJECTIVES
ILLUSTRATION
INSTRUCTIONS
Push both the nail and the wire deep into
the potato. Measure voltage output by the potato battery
with a voltmeter. Now, wasn't that easy?
Seriously, though, experiment with different
metals, electrode depths, and electrode spacings to obtain
the greatest voltage possible from the potato. Try other
vegetables or fruits and compare voltage output with the
same electrode metals.
It can be difficult to power a load with a
single "potato" battery, so don't expect to light up an
incandescent lamp or power a hobby motor or do anything like
that. Even if the voltage output is adequate, a potato
battery has a fairly high internal resistance which causes
its voltage to "sag" badly under even a light load. With
multiple potato batteries connected in series, parallel, or
series-parallel arrangement, though, it is possible to
obtain enough voltage and current capacity to power a small
load. |