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Day 2: Design and Build a Magnetometer
The magnetometer is a glorified compass. The virtue of the magnetometer
is to have the students create the instrument rather than rely unthinkingly
on a 'black box'. The student built magnetometers will be a primitive version
of an instrument that is used on all satellites, is similar to the devices
people to find 'buried treasure' and lost coins in city parks and at the beach,
and is used by photographers trying to get pictures of the aurora. (See Unit Extensions.)
The piece of index card is to allow the students to label the ends of the magnet.
I encourage you to use designations like "End A" and "End B". This may help
the students be a little more involved in what is happening. As soon as we
say "north" and "south" the students may fall into a 'the book says' answering
pattern. It is suggested that you standardize the class reference system so
that all class members use the same direction convention. This will aid in
The magnet must be able to swing in a full horizontal circle in response to
the external magnetic field. The magnet is like the "test charge" used in
electrostatics to measure electric field strength.
This version of the magnetometer is light enough to hang from the ceiling.
This will allow the student to make direction maps of magnetic fields at
different heights relative to various sources. The purpose of this is to help
the students think of magnetic fields as 3-dimensional entities. In all most
all instances, magnetic fields are drawn using a 2-dimensional or planar
representation. The students will discover that the curvature of the field
lines exists in all 3 dimensions.
The Practice Using the Magnetometer task can be done as homework or as an
in-class investigation. If students do this at home, some class discussion
time should be devoted to logistics and how to investigate the behavior under
Add Image of completed SBM
Add image of pre-assembled parts
Lesson Development/Writing: Ed Eckel
Web Design: Theresa Valentine
Last Updated: 8/15/2000
Above is background material for archival reference only.