These effects are derived from two fundamental observations of physics: a steady current creates a steady magnetic field described by Oersted's law, and a time-varying magnetic field induces an electromotive force in nearby conductors, which is described by Faraday's law of induction.
Butter & salt. Preheat the oven to 400 degrees. Husk the corn, wrap each ear in foil, adding 2 teaspoons of butter to each packet. Bake for about 25 minutes or roast the foil-wrapped corn over hot coals turning once during the cooking. Serve with more butter and salt.
Roasting the Corn. Place the corn at the base of the fire covered in coals and ash using a pair of tongs. Ideally you want to cover the foil-wrapped corn husks completely to in that bed of embers to prevent scorching. Each ear takes about 20 minutes to roast. After removing the ears from the campfire with a pair of tongs, allow them to cool for 5 to 10 minutes, until you can easily unwrap the foil and serve.