Elenco Snaptricity&reg - Manual (Page 22)

Educational Corner:
-21-
Pushing a Lot of Electricity Project #12
Wires can generally be as long as desired
without affecting performance, just as
using garden hoses of different lengths
has little effect on the water pressure as
you water your garden. However there are
cases where the length and size of a pipe
does matter, such as in the water lines for
your city. Similarly, wire length and size
are important for electric power lines
transporting electricity from a power plant
in a remote area to a city.
5V
5V
Batteries are made from materials like zinc and
magnesium dioxide, electricity flows as these react
with each other. As more material is used up by
the reaction, the battery voltage is slowly reduced
until eventually the circuit no longer functions and
you have to replace the batteries. Some batteries,
called rechargeable batteries (such as the batteries
in your cell phone), allow you to reverse the
chemical reaction
using another
electric source.
Snappy says voltage is
sometimes called electro-
motive-force (EMF) because
it pushes the electrons
through the circuit.
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Build the circuit as shown; it is the same as the preceding
one except the lamp (L4) was replaced by the motor (M1).
Set the meter (M5) to the 5V setting and the slide switch
(S5) to position C at first.
Assembly
Read the battery voltage on the meter (the top scale), it should
be about 4.5V. Flip the switch to position B; the fan spins and
the voltage drops - more than it did with the lamp.
Turn off the circuit and remove the fan. Turn the switch back on
and read the voltage; it doesn’t drop as much without the fan.
Operation
It takes a lot of current to spin the fan as fast as it would like
to go, and the batteries can’t produce enough. As a result,
the voltage (electrical pressure) from the batteries drops.
It’s a lot easier to spin the motor shaft without the fan on it,
so the voltage doesn’t drop much without the fan.
Description
!
WARNING: Moving
parts. Do not touch
the fan or motor
during operation.
!
WARNING: Do not
lean over the motor.
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