You've felt this. Pulling a sweater off your head. Touching a doorknob in winter. The snap when you peel plastic wrap. Same physics this teacher just showed to 7-year-olds. We've been studying it since 600 BC. We still cannot explain why it works. Thales rubbed amber with cloth and watched it pick up dust. He gave the effect a name. The Greek word for amber is "elektron." Every word for electricity in every language descends from one afternoon in the 6th century BC. Watch the spider trick.…