Liquids that respond to a magnet? This is not science fiction, but science fact. In this segment of Science Xplained, Dr. Ainissa Ramirez shows the wonderful world of ferrofluids, which are iron particles floating in a liquid. When a magnet is nearby, the ferrofluid makes weird shapes and increases in viscosity. Dr. Ramirez also demonstrates how you can make a ferrofluid at home using breakfast cereal.