Students must acquire large amounts of cultural, scientific and technological knowledge in an effort to master the prescribed curriculum. In many cases though, they do not have the opportunity to experience the kinds of phenomena which can enrich their knowledge. Good explanations and complete textual and audiovisual documentation are often useful in presenting a mental model ---at least from the eyes of the facilitator (the teacher). However, this type of expository activity may not be sufficient for achieving full conceptual understanding.
Science laboratories equipped with state of the art equipment help to carry out direct practice with a distinct degree of realism and precision. The apprentices can then formulate their own theses and conclusions as a basis for discussions with others and to build knowledge. These resources, however, are expensive and therefore are often not available to students.
Field work and scale models also replicate direct experiences which help to obtain evidence that permits the construction of knowledge; but everyone cannot go to places to explore the objects under study, nor can scale models capture the functionality that they possess. Consequently, it is not always viable to have a direct experience with real objects, at times because of their size (micro or macro), the limited availability (phenomena of very low regularity) or simply because of costs.
Reasons such as the ones cited above have justified the great efforts of educational research groups in the fields of mathematics, science, technology and engineering to make available to students and teachers technological devices that expand abilities, capture information and permit individuals to discriminate and analyze data.