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Author(s): Nancy Moreno, PhD, Barbara Tharp, MS, Deanne Erdmann, MS, Sonia Rahmati Clayton, PhD, and James Denk, MA.

Lenses and Magnification

Magnifying glasses are single lenses that are convex on both sides. The compound light, or optical, microscope uses two magnifying lenses in series to make things appear much larger to the eye than would be possible with a single lens. The simplest compound microscopes consist of tubes with lenses at each end. Objects can be magnified up to 2,000 times using a high quality compound microscope.

Zacharias Janssen is credited with developing the first compound microscope around 1595. But in 1665, scientist Robert Hooke was the first to use such an instrument to observe the division of plant tissues into tiny compartments, which he termed “cellulae,” or cells. Inspired by the work of Hooke, Anton van Leeuwenhoek, a Dutch inventor, used simple (one lens) microscopes to describe bacteria and protists. Van Leeuwen­hoek’s well-made microscopes magnified objects more than 200 times and allowed him to make very detailed observations. 

Funded by the following grant(s)

Science Education Partnership Award, NIH

Grant Number: 5R25RR018605