Which of the following is a projected teaching aid?

Concept

A teaching aid is classified as projected when an optical device forms an enlarged image on a screen. Non-projected aids are viewed directly and do not require an image-forming projection system.

Application

An epidiascope uses lenses and illumination to project images from opaque materials, and in many designs from transparent materials as well, onto a screen. It therefore belongs to the projected-aid category.

Contrast

• A blackboard is a directly viewed writing and display surface.

• A diorama is a three-dimensional model or scene viewed directly.

• A globe is a directly viewed spherical model of Earth.

Cross-check

The classification test is whether an optical image is thrown onto a screen. That test selects the epidiascope; the other listed aids are observed directly. Therefore, the answer is Epidiascope.