magnetograph
/mæɡˈniːtəˌɡræf/
noun
- An instrument that records changes in the strength or direction of a magnetic field, especially the Earth's magnetic field.
- The scientists used a magnetograph to track fluctuations in the Earth's magnetic field during the solar storm.
- At the observatory, the magnetograph produced a continuous chart of magnetic activity throughout the day.
- The old magnetograph in the museum still works and shows how scientists studied magnetism a century ago.