To study the field around permanent magnets, coils, and electrical devices.

https://www.vernier.com/product/magnetic-field-sensor/

From Fred Kral in our Science Department: In my Physics course, one of the most instructive labs in the electricity and magnetism unit is the measurement of the magnetic field in a coil with electrical current  that we change in a controlled  manner. The mobile phones we have used in the past are not consistent or well calibrated for the purpose of this lab. I would like students to be able to take better measurements. This instrument would give students access to many other labs that can only be done with a reliable instrument.