Throughout history, people have used many methods to clean their teeth. Some ancient people chewed on frayed twigs. Others rubbed their teeth with cloth or swabbed them in vinegar. The Egyptians may have been the first people to use toothpaste when they mixed powdered pumice (a porous rock formed in volcanic eruptions) with vinegar and applied it to their teeth in the 100's B.C. Some toothpastes still contain pumice, but science has since supplied other toothpaste ingredients that the ancient Egyptians never dreamed existed.
Modern society dances to an electrical beat, but sometimes, those powerful electrical fields get a bit out of control. Enter Faraday cages and their shielding action to save the day!
Detectives arrive at a crime scene and lift fingerprints from the murder weapon. They'll use these oily markings to catch their criminal. But how do they match the print to the killer?