Elenco Green Projects - Manual (Page 46)

5V
Project #66 Electricity From Water
Water Light Project #67
Salt and other impurities in the
water react with the electrodes
to produce electricity like the
cola does in project 64. The
voltage produced by the water
is usually lower and water will
not run the LED or clock as
long. Connect the liquid energy source to the
circuit shown here. Fill the compartments
with water. Set the slide switch (S5) to
position C. Set the meter to the 5V setting
to see the voltage produced. The red LED
(D1) may be dimly lit, depending on your
local water supply. If you set the switch to
position B, the voltage may be higher since
the water is not trying to light the LED.
Dissolve some salt in the water in all four
compartments. The voltage will be higher
and the LED should light now. See how
long it lights the LED for.
Try replacing the red LED with the yellow
LED (D5) or the clock (T2). See how long
the water can run the clock. If you would
like to set the time, see page 4.
Assemble the liquid energy source using the instructions on page
4. Build the circuit and connect the red & black jumper wires; the red
wire goes to the copper electrode. Set the meter (M6) to the 5V
setting. Fill the compartments with water. The meter shows the
voltage produced, if any.
Set the meter to the 0.5mA setting to see how much current your
water can supply, if any. If the reading is higher than 0.5mA, push
the press switch to change the current scale to 5mA. (The switch
adds a 47
Ω resistor in the pivot stand to the circuit, changing the
current scale on the meter. It should not be used with the 5V
setting.)
Try dissolving some salt in the water in all four compartments. The
voltage and current should be higher now. If you have some distilled
water, test it too (rinse out the salt water first). The voltage and
current produced should be zero now.
Don’t drink any water used in this project. Wash the electrodes and
liquid holder.
The water in some areas is slightly acidic due to impurities in it. This
may be strong enough to produce electricity by reacting with the
electrodes, similar to how a battery works. These impurities should be
safe to drink. Distilled water has almost no impurities.
0.5mA
5V
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