Elenco Snaptricity&reg - Manual (Page 80)

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Fruit Power Project #70
Snappy says: you are
converting chemical
energy into electrical
energy.
1mA
Some fruits and vegetables have a sour taste because they
are lightly acidic. The acid in them is similar to the material
used in some types of batteries, though not nearly as strong.
The acid in the fruit will react with the copper and zinc
electrodes to make an electric current, just like the “AA”
batteries that run your Snaptricity
® kit or the larger battery
in your family car. As some of the acid in the fruit is
neutralized, the current produced drops.
Description
Read the current from your “lemon battery” on the meter.
Try placing the electrodes in different parts of the lemon to
see how the current changes. You may switch the meter to
the 5V scale to also measure the voltage produced, but the
voltage may be too small to measure accurately with a
simple meter like M5. You may see the current/voltage
slowly drop as the “lemon battery” is used up.
If you don’t measure any current, move the electrodes
closer together or to a different place on the fruit.
Replace the lemon with other fruits or vegetables such as
a tomato, grapefruit, orange, carrot, or onion; see how
much current they produce.
Throw away the fruits and vegetables when you are finished
with this project. Wash off the electrodes.
Operation
Squish or roll a lemon a few times to break up some of the cells
inside (tomatoes or grapefruit also work). Stick the copper and
zinc electrodes into the lemon. Set the meter (M5) to the 1mA
scale and connect the jumper wires to it. Hold the metal snap
of the jumper wires to the electrodes (red to copper).
Assembly
If you want to watch
this for a while without holding it,
place the electrode between two
2-snaps as shown here.