For as long as I can remember, a bar of Ivory soap has been a fixture in our bathroom. It was a classic, a symbol of simple, reliable cleansing. Ninety-nine and 44/100% pure—the commercials ...

Place 2 teaspoons of Epsom salt in its labeled cup. Cut one or two bars of Ivory soap so that each group gets about 1/4 of a bar. Do a demonstration to introduce the concept of a precipitate – ...