Ronald T. Merrill, Professor Emeritus of Earth and Space Sciences at the University of Washington, and author of, Our Magnetic Earth: The Science of Geomagnetism, engages in a lively discussion about multiple broad concepts of science, the Earth’s magnetic field, and geomagnetism.
What is magnetism? What has modern science learned from past experiments in physics? How do animals use magnetism to guide them?
Professor Merrill discusses magnetism, which as he states is a broad field that covers a lot of information, from physics to geology. Magnetism, simply defined, is a class of physical experiences/occurrences that are mediated by magnetic fields. The professor discusses his areas of interest within the general topic of magnetism, such as the Earth’s magnetic field, its properties, what creates it, etc.
Professor Merrill discusses the basic properties of magnetism. He explains how animals in nature sense, and use, magnetic fields. He provides examples of various animals and how they use magnetic fields, such as salmon, birds, etc. Continuing, the professor discusses the strength of magnetic fields, and how animals use tools for navigation, smell being one, and magnetic fields being another. He provides some examples of single-cell organisms and how they use magnetic fields to find their ideal environments to live and thrive.
Going deeper, Professor Merrill talks about other species, and their use of magnetic fields, from bats to mole rats. In regard to humans, some scientists believe that we may have a magnetic sense, although Professor Merrill is quite skeptical at this point.
He talks about some Cal Tech experiments that have contributed to further understanding of magnetic fields, and the possibility of whether humans have a magnetic sense. Professor Merrill states that magnetic fields can reverse periodically, and he explains varied conditions that can produce irregularity. Professor Merrill discusses the Earth’s core and he provides information on electrical currents in relation to magnetic fields.
Wrapping up, the scientific professor provides his thoughts on some historical physics as it relates to magnetism, citing the work of William Gilbert, “the father of experimental physics.”