3B Scientific Set of apparatus for Displaying Magnetic Fields - Manual (Page 2)

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3. Technical data
Connections: 4 mm safety sockets
Plexiglas boxes: 185 x 125 x 40 mm 3
Storage tray: 430 x 380 x 25 mm 3
Weight: approx. 1.5 kg
4. Operation
Additionally required:
Power supply approx. 15 A,
e.g. DC power supply, 0 – 16 V /0 – 20 A U117361
• For the experiment you need to pour a thin
even layer of iron filings on the Plexiglas box.
• When performing the experiment with a day-
light projector place the Plexiglas box on this
and adjust the setting until the image is sharp.
To demonstrate the magnetic field of a current car-
rying conductor, electrical currents of approx. 12 A –
15 A are needed.
• The voltage should be increased slowly starting
from 0.
• It is recommended that the voltage source be
switched off immediately after the lines of the
magnetic field become visible. (There is the
danger that the high current could damage the
copper wires.)
• To enhance the formation of the magnetic field
it might prove useful to softly tap your finger
against the Plexiglas box.
• After completing the experiment pour the iron
filings back into the storage bottle and clean
the Plexiglas box.
5. Sample experiments
5.1 Permanent magnets
5.1.1 Bar magnet
• Place a flat bar magnet on the H in the middle
of the magnet rest.
• Scatter iron filings over the smooth surface of
the Plexiglas box, place on top and gently knock
against it.
• After the magnetic field lines have formed,
demonstrate the distribution of magnetic flux
using the magnetic needle.
5.1.2 Magnetic flux lines between two magnetic
poles, N and S
• Place 2 flat bar magnets in the H in the middle
of the magnet rest so that they attract each
other but do not slide up to each other.
• Scatter iron filings over the smooth Plexiglas
box and place it on top and knock against it
gently.
Between the magnetic poles N and S densely packed
flux lines form which are almost straight at the
center and bend more and more, the further out
they are.
• Demonstrate the outer flux lines using the mag-
netic needle.
5.1.3 Magnetic flux lines between two like magnetic
poles
• Place 2 flat bar magnets in the H in the middle
of the magnet support base so that the two
poles with same polarity are facing each other.
• Scatter iron filings over the smooth Plexiglas
box and place it on top and then gently knock
against it.
No interlocking flux lines form between the like
poles.
5.1.4 Horseshoe magnet
• Place 2 flat bar magnets to the left and right on
the magnet support pad so that the magnetic
poles are antiparallel.
• Add on one side a soft iron bar magnet so that
the magnets together form a horseshoe magnet.
• Scatter iron filings onto the smooth Plexiglas
box, place it on top and then tap it gently.
• After the magnet field lines form use the mag-
netic needle to demonstrate the magnet flux
lines of the horseshoe magnet.
5.1.5 Magnetic shielding
• Assemble a horseshoe magnet as described in
the experiment point 5.1.4.
• Place the soft iron ring in the empty space be-
tween the poles of the horseshoe magnet.
• Scatter iron filings onto the smooth Plexiglas
box, place it on top and then tap it gently.
There is no magnetic field visible within the iron
ring. These follow a path through the iron and the
space within the iron ring remains free.
5.1.6 Magnetic induction
• Place a flat bar magnet on the H in the middle
of the magnet pad.
• Position the soft iron bar on the magnet so that
it only covers about half of it and the soft iron
bar still protrudes into the middle.
• Scatter iron filings onto the smooth Plexiglas
box, place it on top and then tap it gently.
• Demonstrate the polarity using the magnetic
needle.