Electronic media are new tools that teachers are adding to the already conventional overhead transparencies, slides or video films (Falk & Carlson 1992). Videodiscs are one of the best of the new media in that they store a very large number of images, still and fullmotion, at an extremely low cost, and the images can be accessed in a second or less, and controlled exquisitely (Kramer 1991a). Videodiscs are being used by biology teachers in support of lectures (Duhrkopf & Kramer 1991), individualized instruction (Kramer 1991b), and in place of conventional laboratories (Leonard 1989; Fawver et al. 1990). How well videodiscs fulfill their promise depends on the quality and appropriateness of the images, as well as the ease of access and organization for presentations. The teaching community has fairly well agreed upon what should be included in textbooks for freshman biology, be it for a oneor two-semester course or a majors or nonmajors course, as well as what the ancillary printed manuals and guides should contain. In contrast, there is no agreement about the nature of the new electronic media. The extant videodiscs for general biology are each a distinctive creation, reflecting the fact that there are no standards, conventions, or widely-accepted guidelines to shape the products. The producers of these disks are to be commended for their pioneering efforts in providing different models. Out of their efforts will come awareness of what is functional and useful as well as what is not successful. One thing which becomes immediately obvious to the user of these biology discs is that what may work well as a textbook illustration can be a confusing, unattractive image on the current low-density video screen where the resolution is poor compared to the printed page. It apparently is not understood by some of the producers of the videodiscs that only certain items are appropriate for the video screen and many are not. The videodisc should not be thought of as a substitute for the printed page or for the overhead transparency or slide. There is no better medium for words than the textbook. There is no medium that is superior to the transparency for the lecturer to explain complex structure or interactions. With an overhead transparency one can point to specific items or focus the student's attention on fine detail. This is not as feasible with the video screen, even if the player allows imposition of pointers or a few lines of script. However, the videodisc can provide unique contributions to the instructional environment, but there are limits to what it can do comparatively well. Three years ago, Kramer (1991a) provided a review of videodiscs for biology, both for general biology and specialized subjects. At that time there were three discs that supported general biology. Today there are at least twice that number and the newer ones are generally better than the older ones. Thus, it seems an auspicious time to take another look at the current crop of videodiscs. Following is a brief profile of the currently available videodiscs for general biology, with comparable information for each. The discs are designed for college-level general biology; they might be regarded differently if their intended use is for other grade levels. In the descriptions that follow, animations means animated graphics; movies means moving pictures of real objects and events. Single-sided discs have a continuous run time of about 30 minutes; double-sided discs about 60 minutes. Software is available in Macintosh and IBM-compatible versions.
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