Elenco Snaptricity&reg - Manual (Page 24)

1A
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Snappy says: the
best conductor ever
discovered is silver,
which is very
expensive. Copper
is the second best
conductor, and it is
used in almost all
electrical wires.
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Be A Scientist Project #14
1A
Educational Corner:
Some materials, such as metals, have very low
resistance to electricity will make the lamp
bright and give a large current measurement on
the meter. These materials are called
conductors . Conductors have electrons that
are loosely held to the nucleus and can move
easily.
Other materials, such as paper, air, and plastic,
have very high resistance to electricity. These
will turn off the lamp and give a zero current
measurement on the meter even in the 1mA
setting. These materials are called
insulators .
Insulators have their electrons locked in tight
and have no room for more.
Did you ever hear the term “blown fuse”?
Some special wires are designed to
break when an unexpectedly high
current flows through them. These are
called
fuses .
Fuses are designed to shut down a circuit when
something is wrong, such as a component
failure, bad design, or a person using it
improperly. This shutdown prevents further
damage to the circuit, and can prevent
explosions or fires.
Fuses are important for safety and most
electrical products have one, especially if they
use electricity supplied by your local electric
company. Small battery-powered products
usually do not have them because the batteries
are not powerful enough to cause harm.
Some fuses need to be
replaced after they
“blow”, but others
can be reset by
flipping a switch.
Every home has
an electrical box of
resetable fuses, it
may look like this:
This wire melts to
break the circuit.
Build the circuit shown, the can be anything you want. Set the meter
(M5) to the 1A setting.
Assembly
Turn on the slide switch (S5, position B) and touch various materials
between the snaps on the switch and meter. See which materials are
good at transporting electricity by watching the meter current and lamp
(L4) brightness. Try string, the electrodes, a shirt, plastic, paper, two of
your fingers, wood, or anything in your home.
If the meter reads zero, switch it to the 1mA setting to see if there is just
a very small current. To help protect the meter, always switch back to the
1A scale before testing a new circuit.
Operation
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