Projected Visual Aids

Projected visual aids are those which require a projector to display images or visuals on a screen. These aids enhance learning and are effective tools in extension education, especially when addressing groups.

🔹 1. Slides

• A slide is a transparent mounted picture.
• Used with a slide projector, which focuses light through the slide to project the image on a screen.
• Commonly made of glass or plastic.
• Slides must be kept inverted (upside down and reversed) in the projector.
• Direct-type projector.

🔹 2. Film Strip

• A continuous strip of film containing a sequence of still pictures or diagrams.
• Each filmstrip typically contains 30 to 60 frames.
• Sizes:
  • Single Frame: 24×18 mm
  • Double Frame: 24×36 mm
• Used in step-by-step presentations.

🔹 3. Opaque Projection (Epidiascope)

• Used to project images of opaque materials like printed pages, photographs, or objects.
• Requires a powerful light source and mirrors to reflect the image.
• Also called Epidiascope.
• Less commonly used due to heat and size.
• Direct-type projection.

🔹 4. Overhead Projection (OHP)

• Used to project transparent sheets (transparencies) placed on a glass platform.
• The image is projected over the head of the presenter onto a screen.
• Also referred to as an Electronic Chalkboard.
• Reflected and indirect type of projector.
• Common in classroom or seminar settings.

🔹 Types of Projectors

• Direct-type: Diascope, Slide Projector
• Indirect-type: Overhead Projector (OHP), Film Projector

Additional Important Points

• 16 mm projector is commonly used in extension education.
• Types of Projection Screens and Their Usage:

📌 Mnemonics for Quick Revision:

“S-F-O-O = Slides, Filmstrip, Opaque, Overhead”