Audio-visual Phase (First Phase): Before the 1950’s, the term audiovisual education was used (and not E.T.). There were various teaching aids like blackboard, maps, radio, films etc. These were mainly media through which a teacher presented his messages. The materials developed were not systematically based on any psychological principles. Education was viewed primarily as a process of transmitting by a teacher, the messages which he considered important, to students. In a sense, this tradition started with printing technology – books, maps, charts etc. Although a good teacher in his transactions with students, asked them questions etc; and encouraged interaction with them, aids like books, radio or film were primarily non-interactive. This can be represented by the following figure.
Computer and Telecommunication Phase (Fourth Phase): Multimedia, E-mail, internet, intranet and website are used extensively today. There are telecommunication modes through which instructional materials can be given to students. There are many computer software packages developed for school children in many of the school subjects.
These packages also have been used and proved to be effective in terms of time and level of student’s achievement. There are also several organizations established in different parts of the world for the development of software packages. For example, in India we have Audio-visual Research Centres, Educational Media Research Centres and different Departments of Education and Educational Technology which have been developing software packages for the education of children. Many audiovisual programmes are also telecast by Delhi Doordarshan for school children. Many of our progressive schools are also developing educational software packages for children.