The uses of technology in education have kindled great interest in recent years. Currently, considerable resources are being expended to connect schools to the Internet, to purchase powerful (and increasingly affordable) computers, and on other implementations of educational technologies. However, the mere availability of powerful, globally-connected computers is not sufficient to insure that students will learn--particularly in subjects that pose considerable conceptual difficulties, such as in science and mathematics. The true challenge is not just to put the newest technologies in our...