Each learning materials have varying levels, from easy up to the difficult, the real and unreal, from which secure to the difficult in execution, such as electrical subject matter, atoms, molecules, the universe, and other cells.
Pelajarn materials mentioned above, requires thought and patience of a teacher to teach to the students so that they can be understood. There lies the need for instructional media as a tool in the teaching of a material.
Each instructional media have their respective advantages, then it’s expected that teachers can choose the media that suit their needs or learning goals. With the expectation that media use will accelerate and facilitate the achievement of learning goals.
There are several principles that need to be considered in the selection of instructional media, namely:
1) Should any clarity about the purpose and objective selection of instructional media. Is it the media selection for learning, for general information, or just a pastime to fill empty time. More specifically, whether to groups or individual learning, whether the target students in kindergarten, elementary, junior high, high school or elementary school students at the Extraordinary, the urban community or rural communities. Could also be related to differences in objective color, motion or sound. For example a chemical process (pharmaceutical), or surgery study (medicine).
2) Characteristics of Instructional Media. Each instructional media have certain characteristics, in terms of its superiority, how to manufacture or to use it. Understanding the characteristics of instructional media is a must-have basic skills of teachers in relation to the selection of learning media. Besides it gives the possibility to the teacher to use a variety of instructional media are varied.
3) Alternative options, namely the existence of a number of media that can be compared or competed. Thus, teachers can determine which instructional media selection will be chosen, if there is some media that can be compared.
Other than that it was the author gave at the top, according to the principles of instructional media selection Harjanto (1997:238), namely: Goal, Integration (validity), Condition of learners, availability, technical quality, cost
Furthermore, we need to remember together that no one mediapun who are able to explain all the problems or learning the material thoroughly.