ARRL 'magic trick' demo for teachers

ARRL Education and Technology Program Coordinator Mark Spencer, WA8SME shone the spotlight on Amateur Radio and the ARRL during the National Science Teachers Association (NSTA) 54th national conference in Anaheim, California.

Spencer reports some 15,000 teachers stopped by the ARRL booth, and most picked up a brochure.

"I talked with probably 300 educators specifically about ARRL-related programs such as the Teachers Institutes, 'The Big Project' and Amateur Radio on the International Space Station (ARISS)," he said.

After he'd demonstrated what happens when you drop a magnet through a length of non-ferrous metal pipe, one teacher returned the next day with his wife "so I could show her the 'magic trick,'" said Spencer.

The magic trick demonstrates two fundamentals Spencer uses when teaching electronics and electricity:
(1) Moving magnetic fields cause electrons to move, and
(2) Moving electrons create magnetic fields. "When the magnet falls through a non-ferrous metal pipe, the moving magnetic field causes the electrons in the conductor to move," Spencer explains. "Those moving electrons in turn create an opposing magnetic field that prevents the magnet
from falling right through, giving it a 'slow motion' effect."

Spencer says the magnet moves more slowly in a copper pipe than in an aluminum pipe because copper is a better conductor. It falls straight through a PVC pipe because PVC is an insulator. "All of electronics and radio boils down to how we manipulate these two fundamental principles," he
concluded.

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