3B SCIENTIFIC® PHYSICS
Set of Apparatus for Displaying Magnetic Fields U8491790
Instruction sheet
10/07 ALF
1 Cylindrical coil on box made of
Plexiglas
2 Magnet support base with guide
studs on box made of Plexiglas
3 Plexiglas box with smooth surface
4 Scattering bottle with iron filings
5 Flat soft iron bar
6 Soft iron ring
7 2 Permanent flat bar magnet
8 2 Soft iron bars
9 Magnetic needle with holder
10 Straight conductor on box made
of Plexiglas
11 Ring-shaped conductor on box
made of Plexiglas
1. Safety instructions
Currents of approx. 12 A – 15 A are required to demonstrate magnetic field distribution of current
carrying conductors.
• It is recommended that the power source be
switched off immediately once the lines of themagnetic force field become visible. (Danger
that the copper leads are damaged due to the
high current.)
• Do not touch the current carrying conductors
with your fingers.
2. Description
The set of apparatus for displaying magnetic fields is
used to illustrate magnetic field distribution of
permanent magnets and current-carrying conductors. Experiment topics include among others: magnetic flux lines of bar and horseshoe magnets, magnetic screening, magnetic induction, lines of force of
electromagnetic fields of straight conductors, ringshaped conductors, cylindrical coils and electromagnets.
The equipment kit includes 5 Plexiglas boxes as well
as 7 additional accessories (see point 2.1). The Plexiglas boxes used to scatter iron filings on is designed
with a recess so that after use the iron filings can
easily be refilled into the storage bottle. All of the
components are arranged in a componentshaped
premoulded storage tray. The equipment kit is also
well suited for use on a daylight projector.
2.1 Scope of delivery
1 Straight conductor mounted on Plexiglas box
1 Ring-shaped conductor mounted on Plexiglas box
1 Cylindrical coil mounted on Plexiglas box
1 Magnet pad with guide studs on Plexiglas box
1 Plexiglas box with smooth surface for scattering
materials on
2 Soft iron bars
1 Flat soft iron bar
2 Permanent flat bar magnets
1 Soft iron ring
1 Magnetic needle with holder
1 Scattering bottle with iron fillings
1 Pre-moulded storage tray
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3. Technical data
Connections: 4 mm safety sockets
Plexiglas boxes: 185 x 125 x 40 mm
Storage tray: 430 x 380 x 25 mm
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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 carrying 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.
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