The Magnetometer

Adapted from a TOPS Terra Bagga activity

Type of Lesson: Hands-on activity

Time Needed: 25 minutes

National Standards Addressed

Earth and Space Science, Grades 9-12: Movement of matter between reservoirs is driven by the earth’s internal energy and external sources of energy…

Physical Science, Grades K-4: Magnets attract and repel each other and certain kinds of other materials.

Physical Science, Grades 9-12: Electricity and magnetism are two aspects of a single electromagnetic force…

Science and Technology, Grades K-4: Tools help scientists make better observations, measurements, and equipment for investigations. The help scientists see, measure, and do things that they could not otherwise see, measure and do.

Unifying Concepts and Processes, Grades K-12: Models are tentative schemes or structures that correspond to real objects, events, or classes of events and that have explanatory power.

Quick Summary of Lesson

Students will build an instrument capable of detecting a magnetic field and magnetic polarity.


4-inch piece of plastic straw
2 straight pins
masking tape
sewing thread


1. Use a small piece of masking tape to hang two straight pins from a piece of thread. The pins should point in opposite directions and hang horizontally.

2. Push the thread through the straw. Tape the thread to the top so that the pins have just enough clearance to swing freely at the bottom.

3. Stroke the pins from left to right several times with a permanent magnet.

4. Establish and mark the north-seeking end.

Notes to the Teacher

Magnetic fields are invisible; we can only see the effects of the magnetic force. Magnetometers are devices used to detect and measure the strength of magnetic fields. Compasses are basically magnetometers with directions marked on them. A magnetometer will dip or point toward a source of magnetism. Have students use their magnetometer to find things in your room or at home that are magnetic.

Have students tackle these exercises which will have them utilize their magnetometers: Terrabagga Activity and Magnetometer Extensions.

Need More Information? Try Using Windows to the Universe

Please use these links for further ideas or more information:
The Earth's magnetic field
The force of magnetism
Magnetic field
Magnetic material
Magnetism overview
Magnetometer Extensions
Planetary magnetism
Terrabagga Activity
Last modified March 15, 2002 by the Windows Team

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