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During experiments at the Bimini Biological Research Station in the Bahamas, researchers Eric Stroud and Michael Hermann dropped a small magnet in the water beside a shark. The presence of the magnet elicited a distinct reaction from the fishthey darted away from it.
Why the intense reaction? The interaction of salt water and charged metals produces a weak electrical field(电场). When a shark comes close to that field, the field seems to disrupt the sharks‘ special sixth sense, electroreception(电感受). Many shark species have pores dotted around their snouts called ampullae of Lorenzini(洛仑兹壶腹，鲨鱼用它来感受电场信号)that detect minute changes of electricity in the seawater, up to one-billionth of a volt. These electrical impulses come from the tiniest muscle contractions of other aquatic life formsor peopleand are carried through the ions in the salt water.
What does salt water have to do with electricity? Salt water is an ionic solution, meaning it contains particles with unpaired electrons. Because of this quality, salt water can also act as an electrical conductor(导电体). When a charged magnet comes into contact with salt water, the ions flow through the metal to become stabilized, resulting in the electrical field. We know that sharks can sense shifts in the surrounding underwater electrical fields through their ampullae of Lorenzini. Running into these stronger electric fields...