Optics

Abstract

Very convenient light source for optics demos is 35mm projector. Low profile models equipped with zoom lens and 2–position switch for 300W or 500W operation offer greatest flexibility. Second useful source is 25W straight–filament showcase bulb with clear envelope. Covering top and bottom halves with thin gelatin filters (e.g., red and blue) is advantageous for some demos, especially those with inverted images.