Elenco Green Projects - Manual (Page 44)

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Project #62 Liquid Battery
Assemble the liquid energy source using the instructions on page 4. Connect the
red & black jumper wires between the meter (M6) and the electrodes, the (+)
side of the meter goes to the copper one. Set the meter to the 5V setting. Fill
the compartments with cola soda (other flavors also work). The meter should
show a voltage of about 3V. Switch the meter to the 0.5mA setting to measure
the current produced.
Move the copper electrode with the snap on it over to the next compartment, as
shown (“A”). Use the 5V setting to measure the voltage and the 0.5mA setting
to measure the current. The voltage should only be about 3/4 of what it was,
since you have one less compartment. The current should be about the same.
Now move the copper electrode with snap to the next compartment, so only two
are used (“B”) See how the voltage drops even more, but the current changes little.
Now move the copper electrode with snap to the same compartment as the
electrode with snap, so you only have one cola “cell” (“C”). Measure the voltage
and current now.
Don’t drink any soda or juice used in this project. Wash the electrodes and liquid
holder.
Note: Your actual results may vary. Your M6 meter is a simple meter; don’t
expect it to be as accurate as normal electronic test instruments.
Project #63
Juice Battery
Cola-flavored soda is lightly acidic. The acid is similar to the
material used in some types of batteries but not as strong.
The acid in the cola reacts with the copper and zinc
electrodes to make an electric current, just like a battery. As
some of the acid in the soda is used up, the current
produced drops.
Each of the compartments in the liquid energy source
produces about 0.75V, though the current is low. When the
four compartments are connected in a series, their voltages
add together to make about 3V total, but the current is the
same. Each compartment is like a cell of a battery. Your B4
rechargeable battery actually contains three 1.2V “cells” in
a series, just like the “cells” of the liquid energy source.
Soda can be used in this way to produce electricity, but it
does not produce very much, so is not widely used.
However, biomass power plants, which burn decaying food
products and yard waste, are increasingly being used.
These plants produce electricity from garbage that would
otherwise be filling up landfills, and they don’t pollute the
environment.
Replace the soda in the
liquid energy source
with fruit juice. Sour
tasting juices like lemon
or grapefruit work best.
Measure the voltage
and current for your
juice battery like you did
with the soda. Try
different juices and
compare them. Don’t
drink any soda or juice
used in this project.
Wash the electrodes
and liquid holder.
Some fruits and
vegetables have a sour
taste because they are
lightly acidic. This acid can
be used to produce
electricity just like the cola
and batteries do.
Using the natural chemical
energy in fruit is a very
green (environmentally
friendly) way to produce
electricity.
Zinc
electrode
Copper
electrode
B
C A
5V 0.5mA