3B Scientific Inclination Instrument User Manual

3B SCIENTIFIC® PHYSICS

Inclination Instrument U21900

Instruction Sheet

11/08 ALF

1 Base
2 Pillar
3 Scale ring
4 Connecting sockets
5 Cradle
6 Magnet needle

1. Description

The inclination instrument is used to measure the
inclination of the earth’s magnetic field, and to
demonstrate the magnetic field produced by a
current-carrying conductor.

The instrument consists of a acrylic base with a pillar
which supports an axially rotatable cradle carrying a
magnetic needle and a scale ring. The magnet
needle is mounted on a bearing consisting of sharp
tips, and is free to rotate in either a horizontal or a
vertical plane according to the direction of its axis.
The sockets on the cradle can be used to pass a
current of up to 5 A through it.

2. Technical data

Diameter of circle: approx. 110 mm
Length of magnetic

needle: approx. 100 mm
Cradle length: approx. 150 mm
Voltage: max. 30 V
Current: max. 5 A
Terminal: 4 mm safety sockets
Base dimensions: approx. 100x90x185 mm³

1

3. Operation

3.1 General precautions

• Protect the instrument from moisture, dust and

mechanical shocks.

• Avoid touching the magnet needle.

The geometry of the earth’s magnetic field lines can
be greatly altered by static magnetic fields, steel
frames of laboratory benches and equipment, and
steel supports in the floor, ceiling and walls of
buildings. For this reason the measured angles may
sometimes differ widely from the expected values.

3.2 Measurement of the inclination

The magnet needle aligns itself along the direction
of the earth’s magnetic field.

• With the scale ring in the horizontal plane, turn

the instrument so that the blue end of the
magnet needle is at 0° (the blue end of the
needle is its north-seeking pole).

• Next turn the cradle through 90° (the plane of

the scale ring is then vertical). The blue end of
the magnet needle is inclined downwards.

The angle between the magnet needle and the
horizontal plane is called the inclination. It differs
from place to place. At a latitude of about 50° north
(Europe) the inclination is 63° to 68°.

3.3 Magnetic effect of an electric current

In order to carry out the experiment, a variable DC
current source is also needed, such as:

1 DC power supply 0 - 20 V, 0 - 5 A (230 V, 50/60 Hz)
U33020-230
or
1 DC power supply 0 - 20 V, 0 - 5 A (115 V, 50/60 Hz)
U33020-115

• With the scale ring in the horizontal plane, turn

the instrument so that the blue end of the
magnet needle (its north-seeking pole) is at 0°.

• Connect the sockets on the instrument to a

variable DC current source.

As the current is increased, the needle is deflected
increasingly from its original direction.

When the polarity is reversed, the direction of the
deflection changes.

3B Scientific GmbH • Rudorffweg 8 • 21031 Hamburg • Germany • www.3bscientific.com

Subject to technical amendments

© Copyright 2008 3B Scientific GmbH