States of Matter in a Baggie. I would use this activity to teach my students the science of the states of matter. With this hands on activity they will be able to have a visual representation of a difficult concept.
Hot ice, scientifically known as sodium acetate, is a liquid that will turn solid at the slightest provocation. Touching it with your finger, bumping it too hard, or speaking a few angry words will cause it to spring from a clear, water-like state into solid ice-like crystals.