Global Geomagnetism Measurement Activity

Geomagnetism in the palm of your hand.

About

The year 2022 marked the 300th anniversary of George Graham's discovery of daily magnetic declination, as well as the 190th anniversary of Carl Friedrich Gauss's measurement of the Earth's magnetic field strength. Commemorative geomagnetic measurement activities were held worldwide.

Under the guidance of May Inn Sim of the National University of Singapore, the IEEE Magnetic Society's Students in Magnetism (SiM) launched an initiative named "MagnetiSiM 2022: How on EARTH do we measure the EARTH's magnetic field?", aimed at encouraging learners of all ages around the globe to participate in geomagnetic measurements.

In the same year, the United Nations introduced the "International Year of Basic Sciences for Sustainable Development." Among the series of activities organized by the United Nations, a noteworthy one involved geomagnetic measurements conducted in regions located at the Earth's antipodes.

In Taiwan, the Physical Society of Taiwan collaborated with the United Nations' initiatives, promoting a geomagnetic measurement project led by Professor Chun Chuen Yang of the National Central University, Taiwan. Students from elementary schools to universities across Taiwan were invited to record the variations in geomagnetism from July 1, 2022, to July 1, 2023, documenting changes every 15 days.

Concurrently, Professor Silvina Ponce Dawson from the University of Buenos Aires in Argentina, which is antipodal to Taiwan, also encouraged her students to engage in geomagnetic measurements. Students in both locations utilized their own mobile phones and an app called "Phyphox" to measure the magnetic field, and they shared the measurement data in a uniform data format.

Professor Kathy A. Whaler of the University of Edinburg also participated in the video conference discussions and provided suggestions. She will also represent this activity by reporting its results at the International Union of Geodesy and Geophysics.

For students, the use of readily available hardware and software to perform geomagnetic measurements allowed this scientific activity to permeate daily life. By comparing the data from both locations, students could understand that geomagnetism is not perfectly symmetrical. A year-long observation gave participants an understanding that detecting changes in geological activity requires long-term observation. Although the precision of measuring geomagnetism with mobile phones doesn't match that of professional equipment, such activities undoubtedly have a profound impact on earth science education for young students.

Hover over the dots to find your submissions!

Submissions from citizen scientists

Disclaimer: The data points on this chart are from the original data of volunteers from around the world. Without professional review, they may be affected by the experimental environment and geology at the time of measurement and deviate from the actual values. They are for reference only!

Measurement Methods

A variety of methods can be used to measure the Earth's magnetic field with our phones!

NOAA is a resource site which provides theoretical data for magnetic field strength, magnetic declination, and magnetic inclination, which is corrected for GPS geographical location, the phone’s orientation towards true north is first calibrated using the NOAA website before it begins recording local geomagnetic measurement values, and the theoretical values at that moment are recorded.

Phyphox is a mobile app that provides measurements of the magnetic field in the x, y, and z axes. Converting these measurements to actual magnetic declination and inclination requires trigonometric calculations

Magnetic Inclination and Declination

The geomagnetic measurement data of magnetic declination and magnetic inclination from Taoyuan, Taiwan, and Buenos Aires, Argentina. Taiwan presents results from July 1, 2022, to July 1, 2023; Argentina presents data from May 18, 2023.

A 90 degree difference in magnetic inclination measured in Taiwan and Argentina accommodates the fact that when most smartphones are placed horizontally, the definition of the horizontal plane differs by 90 degrees at the respective locations.

Time-dependent Field Evolution

Geomagnetic measurement data from the Taoyuan region in Taiwan from July 1, 2022, to April 1, 2023. The red solid points represent theoretical values, while the black solid points represent measured values.

Due to the precision of the smartphones and the calibration differences between different smartphones used by the participants, there are significant discrepancies between the measurements taken every 15 days and the theoretical values.

Check out the latest data from the students in Taiwan here!