Zapping stones
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Zapping stones How magnetic lodestones are born
Photo on right: Rocket-triggering research at Langmuir Laboratory for Atmospheric Research, New Mexico, 2012. Photo by Jacob Trueblood. Courtesy of Langmuir Laboratory.
I
used to own a lodestone—a magnetic mineral. I don’t have it anymore because I lent it to someone and can’t remember who borrowed it. After it went missing, I realized how much I appreciated that hunk of earth. It was craggily, softball-sized, and seemed out of place on my organized desk. To make it look more appropriate for an office setting, I stuck a few paper clips on its side, which teased gravity. I really enjoyed looking at that old rock. One night, I was preparing notes for the following day’s lecture on magnetism and was looking for a neat fact or two to share with my students. I hoped to make the topic enticing, particularly to the apprehensive liberal arts majors, so I dove into a few textbooks and began hunting. Staring at the empty space where my lodestone formerly sat, I was inspired to learn more about it. However, it was late, and I had to choose between finishing my notes quickly or following my curiosity about magnets. My curiosity won won. I dug frantically for fac facts. First, I scanned a large stack of textbooks, but th they didn’t offer much. In fact, they furnished nno history at all and started the topic of magne magnetism with a description of quantum mecha mechanics. I knew that would not engender w warm feelings from my students, so k digging. I kept I dashed downstairs to the buildiing’s library and combed a pile of rrecent papers on lodestones and a m mountain of rare, old magnetism bo books. The papers provided a few
gintriguing facts, like birds use maghat nets to navigate. Turns out that birds have special cells tuned to h the magnetic field of the earth that guide them. Sea turtles do too. I knew my students would enjoy these nuggets, so I unearthed more. There are some ded in bacteria that align along a magnetic field. Embedded hem to their cell membranes are tiny iron crystals that cause them m move with a magnet—whether they want to or not. Another gem. Hours passed and a long night of writing waited. But, I had one more question: “Where do lodestones come from?” That seemed like a simple question with a simple answer. It wasn’t. I uncovered a paper from the 1930s that stated lightning created lodestones. That information struck me hard. But, my curiosity had to wait. It was very late and work beckoned. That night, I wrote my notes thinking about lodestones and lightning. A few weeks later, on a cold December evening when the snow left me little opportunity to do anything else, I went back to this lodestone bombshell. Perplexed, I wanted to find out if lightning indeed made lodestones. So I spent the evening sending emails to scientists who could confirm this. A few days later, I received a reply from Peter Wasilewski, a retired NASA scientist. He returned from giving lectures on a cruise and had time to speak about his work with lightning. I was thrilled. Now,
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