# Solar Storms and You!

## Activity 7: Magnetic Storms from the Ground

### Introduction

Coronal Mass Ejections and other solar storms can buffet the magnetic field of the Earth with clouds of charged particles and magnetic fields. Not only do these interactions affect the large scale properties of the geomagnetic field, but their affects can also be easily detected on the ground. During the last 100 years, many 'magnetic observatories' have been commissioned around the world to monitor the Earth's surface field conditions. These have been, historically, important for navigation by ships at sea. The data from these observatories can also be used to examine what happens when solar storms arrive at the Earth.

### Objective

By analyzing graphical data, students will become familiar with the Earth's changing magnetic field through solar storm activity plots.

### Materials

5 station magnetic field data sheet for Students and Teacher's Answer Key
Calculator

### Procedure

1. Plot the location of each magnetic observatory on a map of Canada. Label each station number next to the plotted point.
2. Analyze the magnetic intensity plot for each station and identify the difference between stable activity, and the largest difference in change of activity, either positive or negative, on the plot.
3. Find the percentage change for each station. Round the answer to the nearest hundredth of a percent. Write the number below the location of the station on the map. See the Teacher's Answer Key.
4. Discuss and work the following questions and procedures: a) Where are the largest magnetic changes located for this event? b) Draw a circle around the three stations with the largest magnetic changes. Did the largest changes occur at the same time? Explain. c) On the data sheet, organize the plots in order from the largest to the smallest change. Do you see any patterns? d) Organize the magnetic intensity plots according to similar shapes. Are there any trends?

### Example

For Fort Churchill the normal 'stable' level was 59.3 and the largest deflection happened near 8:00 at about 59.8.
% = 100 x (max - stable)
stable

% = 100 x (59.8 -59.3)
59.3

or 0.85 percent

### Conclusions

Students should have learned that the Earth's magnetic field does not remain constant  in time, but can change its strength. By investigating and plotting data, students should have revealed the changes in the Earth's magnetic field due to solar storms. From this, students will locate those regions of the Earth that are most susceptible to solar storms.

### Related Web Resources

Visit the IMAGE/POETRY Magnetic Observatories page and from there, you can look at recent data on the earth's ground-level magnetic field from the observatories 'minute to minute' realtime measurements.