Types of software for the OHP
Basically there are three packs available.
 
Theme-bound series, often of German origin, containing 5 to 40
transparencies, designed to teach one complete subject with the help of student worksheets.
Transparency series linked to a textbook that students use with a
selected number of images from that book. Publishers provide these these packs to help teachers to work more effectively with the book.
 
OHP-encyclopedias with the most important topics arranged for
each school subject offered in secondary programs such as Geography and Physics. These encyclopedias are visual data banks designed for students from class one to end grade. The encyclopedias are also suitable for higher education programs as they contain a wide range of rich, visual data to illustrate specific concepts or provide an overview.
 
 
Varying opinions of what types of packs are usefull. Some overhead projector-users want to use only those transparencies which show the same images presented in their student's textbooks or CDs. In this way, students can view the images again at home. Other users view transparencies as extra teaching tools to provide visual clues. They often consider transparencies cost effective and more flexible than wall charts and maps or use them as part of their multi-stimuli lesson strategy.


TTE's Visual Geography Encyclopedia with 587 transparencies