Media is the translation of English media, which refers to the carrier of information and the tool for transmitting information. The common features of the media are as follows:

1) fixity

Media can record and store information so that it can be copied when needed. For example, the printed media directly fixes the text symbols on books; Electronic media convert language, characters and images into sound, light and magnetic signals and fix them on films, tapes, magnetic disks or optical disks. This feature of the media enables seniors to gradually accumulate rich practical experience and pass on valuable knowledge and skills to future generations.

2) Diffusibility

Media can transmit information in various symbolic forms to a certain distance, so that information can be reproduced in an expanded range. In ancient times, "a scholar stays at home and knows what's going on in the world" depends on this feature of the media. In the second half of the 20th century, when electronic information technology made great progress, it was not surprising that McLuhan put forward the concept of "global village".

3) Repeatability

Media can be reused. If well preserved, these media can be used repeatedly as needed, and the quality and quantity of information they present are stable. In addition, it can make many copies and use them in different places at the same time.

4) Composability

Several media can be used in combination. This combination can be that in an activity, several media are arranged properly, used in turn or presented with their own information at the same time; You can also combine the functions of various media to form a multimedia system, such as audio-visual synchronous slide show and interactive video system. Combination also means that the information contained in one medium can be transmitted through another medium, such as pictures and models, and can be presented on the screen through movies, videos and other media. Multimedia computer embodies this feature.

5) Instrumentality

Compared with people, media is in a subordinate position. Even the modern media with advanced functions are still created and manipulated by people. Media can only expand or replace some functions of people, and appropriate teaching media need to be carefully compiled or prepared by teachers and designers. Facts have proved that even computer-aided teaching with certain intelligence will not make teachers unemployed, but will only prompt teaching designers to think about the rational distribution of human-computer functions.

6) initiative

Under certain time and space conditions, the media can operate independently without human activities. For example, excellent video teaching materials or computer-aided teaching courseware can really replace teachers. Elaborate teaching media generally conform to the principle of teaching design, and adopting the best teaching scheme, especially the teaching media designed and compiled by experienced old teachers, will have better teaching effect than young teachers who lack teaching experience.