Under a White Sky: The Nature of the Future

by Elizabeth Kolbert

“The electric-field strength is increasing as you move from upstream to downstream or vice versa, so if my hand were a fish, its nose is here,” he continued, indicating the tip of his middle finger, “and its tail is here.” He pointed to the base of his palm, then set the outstretched hand wiggling. “What happens is, the fish is swimming in, and its nose is experiencing one electrical voltage, and its tail is experiencing another. That’s what makes the current actually flow through the body. It’s the current flowing through a fish that will shock them or electrocute them. So a big fish has a big voltage difference from its nose to its tail. A smaller fish doesn’t have that much distance for the voltage to cover, so the shock is smaller.”