BIOL-2026EL Study Guide - Final Guide: Optical Microscope, Oil Immersion, Numerical Aperture
Document Summary
The compound microscope is a basic tool used in microbiology laboratories. This precision instrument is equipped with several lenses that allow the magnification of a specimen up to a thousand times its actual size. The mechanical adjustments and physical features of the microscope allow a wide range of possibilities for observing various types of microorganisms. To achieve magnification in a bright field of view, the microscope combines an optical system and an illumination system. The bright light that is projected towards an object on the stage passes through a series of lenses. The projected light initially is collected and concentrated by a condenser. It is then directed upwards through the object and is collected by the objective lens (near the object) to form a magnified image. This enlarged image becomes an object for the ocular lens (near the eye), which magnifies the object further to form an image visible to the observer.