1. Activate students’ prior knowledge.
Ask: What do you already know about magnetic fields? What everyday object can you think of that measures magnetic fields? Elicit from students that a compass uses Earth’s magnetic field to give information about direction. Then show students the NASA video “Magnetometry 101.” Ask them to restate in their own words how magnetic fields can be measured and drawn. Tell students that, in this activity, they will build their own magnetometer to monitor and measure magnetic fields.

2. Analyze an illustration and discuss magnetic storm prediction via magnetometers.
Display for students the NASA illustration “Electromagnetic Radiation into the Atmosphere.” Explain to students that Earth's magnetic field is shaped and controlled by the sun. Ask students to describe what they observe in the image. Point out how the solar flare produces a solar wind. The solar wind pushes the ions around Earth's magnetosphere. Solar wind will push the magnetosphere to a dynamic state called a magnetic storm. A temporary buildup of energy in the portion of Earth's magnetic field farthest from the sun is suddenly released through a partial collapse of a small part of the magnetosphere and redirected toward the poles. Ask: How do you think scientists track changes in the magnetic field? How does that give them information about magnetic storms? Explain to students that magnetic storms are caused by temporary changes in the magnetic field. Scientists measure the strength and direction of Earth's magnetic field with magnetometers placed all over the world. Most are placed near the polar regions, where the magnetic field is known to change quickly.

3. Divide students into small groups and have them select roles.
Divide students into small groups of four. Have students choose from the following roles:

• Recorder—reads directions, records data
• Materials handler—gathers, organizes, measures, and glues materials needed for task
• Engineer—assembles parts as instructed by materials handler
• Project Manager—coordinates and ensures job is on track for completion and all duties are being completed; enlists assistance of other team members as needed; completes checklist as steps are completed

4. Have groups build magnetometers.
Distribute two sets of handout Build a Magnetometer and worksheet Magnetometer Data Collection to each group. One set is for the recorder and the other is for the project manager. Project the step-by-step illustration showing how to build the magnetometer for students to refer to as they assemble theirs. Caution students to take their time and be careful during the construction period. Allow ample time for groups to construct their magnetometers. Rotate around the room and support students in fulfilling their roles, as needed.

5. Provide opportunities for students to gather data fifteen times.
If possible, set up the magnetometers in a place where they will not be disturbed. Determine the best method for data collection, making sure students have the opportunity to gather data a total of at least fifteen times, and record it in Part 1 of the worksheet Magnetometer Data Collection. Then have students graph their data in Part 2 of the worksheet.

6. After students have gathered enough data, have groups compare their data.
Have a whole-class discussion in which groups compare and contrast their data. Ask:

• What similarities and differences do you see between the data sets?
• What are some possible explanations for any similarities or differences?

Note that students should see similar data if data is collected at the same time from the same magnetometer, or if the magnetometers are close in proximity. If the magnetometers are in very different locations, students may see a fluctuation in data. There may also be differences in the data sets if measurements are not taken precisely or if students round measurements.

7. Have groups compare their data to USGS data.
Display the USGS: National Geomagnetism Program real-time page, or print the data. Have students select the site that is closest to your location. Note that data is displayed for a 6-day period. The data unit is recorded in nanotesla (nT), but you can use the data to make general observations. Have groups compare their graphed data to real-time USGS data. Ask:

• What similarities and differences do you see between the data sets?
• What are some possible explanations for any similarities or differences?
• What modifications to the experiment would be beneficial? Why?

Students should see similarities in the data. If they see differences, it may be due to the differences in locations or their methodology for data gathering. Depending on initial data gathering, students may want to change their methodology and see if they get similar results.