ADVANTAGES OF OHP

brightness

2. Direct eye-contact

3. Ease of use

4. Abundance of materials

5. Manipulable

6. Availability of materials

7. Self-prepared materials

8. Advance preparation

9. Impact on attitudes

Wharton Applied Research Center , 1981

More individuals followed the recommendations of presenters who used OHP than those who did not Presenters who used OHP were perceived as better prepared , more professional , more persuasive , more credible and more interesting Groups that used OHP more likely to reach consensus on their decisions

Cabeceiras , 1972 10. Organisation & discussion

Teachers who use the OHP tend to be more organised Students participated more frequently in discussion

LIMITATIONS

1. Not preprogrammed effectiveness depends on the presenter cannot display visual sequence or audio

2. Not self-instructional Designed for large-group presentation Not suitable to independent study Captions & audio tracks would not be self-instructional

3. Production process required Printed materials & nontransparent items cannot be projected immediately Have to transfer into transparencies first Example : magazine illustrations

4. Keystone effect Misrepresentation of images is more common than other projection systems Discrepancy in levels causes a distortion referred to as the ‘keystone effect’ projector commonly placed at desktop level to facilitate the instructor’s writing on transparencies the screen needs to be placed on a higher level for unobstructed audience sightlines