ARNING: Always check your wiring before
W
turnin g o n a circuit. Never l eave a circ uit
unatte nded while the batter ies are inst alled.
ever connect additional batteries or any other
N
ower sources to your circuits.
p
Electromagnetism
Model SCP-08
WARNING: SHOCK HAZARD -
Never connect Snap Circuits
o the electrical outlets in your
t
home in any way!
®
Project #1
All materials have tiny particles with magnetic charges, which are usually so
well balanced that you do not notice them unless a magnetic field disturbs them.
Magnets are materials that concentrate their magnetic charges at opposite
ends. One side attracts while the other repels, but the overall material is neutral.
The earth we live on is a giant magnet, due to its iron core. A compass needle
always points north because it is attracted to the earth’s magnetic field.
Magnets & Electronic Magnets
Build the circuit shown. Place the iron core rod inside the
electromagnet (M3), and install three (3) “AA” alkaline
batteries (not included) into the battery holder (B3).
Hold the electromagnet near something made of iron and
push the switch (S2). While pressed, the electromagnet will
attract small iron parts like nails or will stick to a hammer or
refrigerator. Release the switch and the attraction disappears.
Pressing the switch turns on an electric current
which transforms the electromagnet from an
ordinary coil of copper wire into a magnet.
Notice that the magnet will attract
small iron parts and stick to things
like the electromagnet did.
An electronic magnet is
better than an ordinary
magnet because you
can turn it on or off with
a switch.
Large electromagnets
are used to move
things around at
factories and junkyards.
An electric current
flowing in a wire has a
tiny magnetic field. By
looping a long wire into a
coil the tiny magnetic
field is concentrated into
a large one.
The strength of the
magnetic field depends
on how much current is
flowing in the wire and
how many loops of wire.
If you have any problems, contact Elenco
®
Copyright © 2010 Elenco®Electronics, Inc. All Rights Reserved. • 150 Carpenter Ave. • Wheeling, IL 60090
(800) 533-2441 Fax: (847) 520-0085 • e-mail: elenco@elenco.com • Web site: www.elenco.com or www.snapcircuits.net
753153
Project #2
2
5
Magnetic Fields
Note: the compass
needle may point
opposite to how it’s
shown here, depending
on how you connected
the jumper wires.
6
1
3
1. The magnetic field is an area around a magnet where it
can affect other objects. It is strongest at the ends of the
magnet. Use the circuit from the preceding project to
compare the magnetic fields of the electromagnet and
magnet.
Hold your compass next to the electromagnet and push
the press switch (S2). Move the compass all around the
electromagnet and watch where the compass points.
Shake the iron filings pack to spread the filings evenly,
then move the pack around on top of the electromagnet
and see how the fillings change (fresh batteries are
recommended, and the fillings may not move much). Do
the same with the magnet.
2. The magnetic field created by a magnet occurs in a loop.
You can see this using paper clips.
3. Loop two paper clips together. Hold them near the
magnet, and move them around it to see the magnetic
field. Do the same with the electromagnet, with the
switch pressed.
4. Hold the compass near the electromagnet and note the
orientation of its arrow. Next, flip the electromagnet
around, reversing the wires to it. Now the other side of
the compass needed is attracted to the electromagnet
(magnetic field is reversed). The direction of a magnetic
field from a current flowing in a wire (or coil of wire)
depends on the direction of the electric current.
5. Remove the iron core rod from the electromagnet. Now
push the press switch again and try to pick up things with
the electromagnet. The attraction is now very weak.
The iron core rod concentrated the magnetic effects of
the electromagnet. You can use the compass to see that
electronic field is now much weaker.
6. Materials made of iron concentrate their magnetic effects
at both ends. The center of the material is magnetically
neutral because the attraction from each end is the same.
The magnetic field created by the electromagnet works
the same way. It is strongest at both ends but neutral in
the center. But the electromagnet is hollow - so iron at
one end will be sucked into the middle.
Lay the electromagnet on its side. Hold the thin rod next
to the center hole and push the press switch to suck it
inside. Hold the switch and gently pull the rod to see how
much suction the electromagnet has.