Where is North?

• Take measurements of the Earth's magnetic field at your specific location to obtain values of:
  • The Earth's magnetic field strength;
  • The magnetic field declination;
  • The magnetic field inclination (dip).
• Learn about the three-dimensional structure of Earth's magnetic field.

This activity can be used as a lab activity in an introductory geoscience course that contains a discussion of Earth's magnetic field. This activity could nicely introduce such topics as Space Weather, Aurora, Paleomagnetism, Magnetic Field Surveys, or Orienteering. Instructors could also use aspects of this activity in an interactive lecture.

This activity requires a microcomputer, multi-sensor interface, and magnetic field sensor. The specific activity is included in Earth Science With Computers by Robyn Johnson, Gretchen Stahmer DeMoss, and Richard Sorensen published by Vernier Software (more info) , with a site license for $45.00. The complete activity in pdf format can be viewed at Where is North The cost of an interface and a magnetic field sensor are $220 and $54 respectively.

Students can also use a graphing calculator with the interface and sensor.

Comparable equipment can also be purchase from Pasco Scientific.

This activity will take approximately 2 hours to complete in a lab setting with some extra time possibly needed for students to answer questions and summarize their results. The activity description at Where is North comes complete with two pages of Teacher Information.

Doing parts or all of this activity as an interactive lecture is also an option.

The activity comes with very specific instructions and related questions. The Teacher Information section contains answers to most questions for easy assessment of student understanding. "Extension" ideas are also provided. Having students design their own experiment for an "Extension" investigation can help you better assess their ability to synthesize what they have learned and to apply this knowledge to a slightly different situation.

One possible extension activity would be to have students measure the magnetic field strength (or dip) every 4 meters for a 60 m line across campus and then graph their results. In essence, they would be performing a small scale magnetic survey. If their line goes over or near magnetic materials, they can possibly see these signals in their survey results.

Vernier Software (more info) has several other sample geoscience labs from Earth Science With Vernier available in pdf format as examples at other examples . These include "Comparing Sunscreens", "Reflection and Absorption of Light", and "Water Quality-TDS (Total Dissolved Solids)".

Pasco Scientific has about 13 online geoscience related lab activities available for free. These are mostly geared towards high school students but can easily be modified for an introductory college level course as either a laboratory activity, a special project, or an interactive lecture example.