Elenco Green Projects - Manual (Page 59)

0.5mA
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Electrical Material Checker
Project #91 Remote Water Heater
Some materials, such as metals, have
very low resistance to electricity and
will turn on the horn. These materials
are called conductors.
Other materials, such as paper, air,
and plastic, have very high resistance
to electricity. These will not turn on the
horn. These materials are called
insulators.
Copper is one of the best conductors
ever found so it is used for most
electrical wires. Plastic is a very good
insulator so it is used around copper
wires to prevent electricity from getting
in or out of the wire.
Build the circuit, place the wind fan
on the motor (M4), and set the meter
(M6) to the 0.5mA scale. Place the
circuit so wind is blowing on the fan
or sunlight is shining on the solar cell
(B7). Set the slide switch (S5) to
position B if you have wind or to
position C if you have sunlight.
Connect the jumper wires to the
circuit and place the other ends in a
cup of water, make sure the metal
parts aren’t touching each other.
Your power source (wind or sun) is
making an electric current flow
through the water, and the meter
measures the current. As the current
flows through the water, the water is
warmed.
Project #92
Build the circuit shown, and touch
various materials between the snaps
marked with .
The horn (W1) will signal for materials
that are good at transporting electricity.
Try string, the electrodes, a shirt, plastic,
paper, wood, or anything in your home.
Many electronic test instruments test
wires and connections using probes and
a sound device like you did here. A
sound device is used so the user can
focus his attention on where he puts the
probes without looking at a display.
You can replace the horn with the meter
(0.5mA setting) or one of the LEDs (D1 &
D5) to make a visual continuity checker.
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These small wind and solar power
sources may not produce enough
heat for you to notice the water
getting warmer, but you could use
more powerful ones to heat up a lot
of water. You could then pump the
water around your house in pipes to
use the wind or solar heated water to
warm up your house.
How do you harness the wind to heat
your house? It is easy when you use
electricity to help.
Another way to harness sunlight to
heat homes is by using sunlight to
heat water, then pumping the water
around the house.
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See projects 1 & 3 if you need to
recharge the battery (B4).