This is an activity about the properties and characteristics of Earth’s magnetic field as shown through magnetometer data and its 3D vector nature. This resource builds understanding of conceptual tools such as the addition of vectors and... (View More) interpreting contour maps displaying magnetic signature data. Learners will make several paper 3D vector addition models, watch podcasts on how to analyze magnetometer data, and employ 3D vector plots to create a model of the 3D magnetic field in the location of the magnetometer closest to their town. This is a multi-step activity with corresponding worksheets for each step. The activity uses data from the THEMIS (Time History of Events and Macroscale Interactions during Substorms) GEONS magnetometer, and requires the use of a computer with internet access and speakers, 2-inch polystyrene balls and bamboo skewers. This is activity 16 from Exploring Magnetism: Earth's Magnetic Personality. (View Less)