There are two kinds of learning going on in high school chemistry classes. The more obvious one is the empirical knowledge, the terms and actions of the science of chemistry, which always serve us well in everyday life even if we do not make science our career. But the other form of knowledge, the cognitive processes, are absolutely invaluable. The taxonomies of the elements, represented so powerfully in the visual arrangement of Mendeleev's Chart, teach us how to gather the units of any set into coherent, workable groups (for example, kinds of cars, kinds of animals, kinds of entertainments, kinds of information retrieval methods, etc.); the carefully designed chemical experiments teach us how the order of steps in a process is important for reliable, predictable results (for example, in building a structure, in baking a cake, in planning a trip, etc.) the way in which elements combine into molecules and the way that molecules combine into substances are indispensible skills in all disciplines; the exchanges of energy, in all their complexity, are learned and demonstrated, often in highly visual ways. The ever-present dangers of chemicals teach us the importance of care and precaution, and the difference between seriousness and horseplay. In other words, the chemistry class is the training ground for logical thought, for organizing knowledge into useable patterns, for beginning the conscious use of our reasoning abilities for solving problems, a necessary passage from childhood to maturity. And for many, it is the first stepping-stone to a life of scientific inquiry.