T e a c h e r  C r e a t e d  L e s s o n

Microorganisms in the 21st Century (part 1)

mbeall

CHIN, Gatineau, Quebec

Development of the Optical Microscope

Hans and Zacharias Janssen are thought to have made one of the first microscopes (a compound model, using two lenses) in Middleburg, Holland, around the year 1595.

The 18th century was a period of several mechanical improvements to the microscope, such as mechanisms for focussing, changeable objective lenses, specialized stages to accommodate different types of specimens, and raised stages for better illumination of specimens from below. By the end of the 18th century, there were mechanical stages that allowed moving the specimen in two directions.

Microscope makers during the early 19th century made two important improvements to the quality of the optical image. One improvement in lens-making corrected chromatic aberration, an optical effect resulting in images with coloured edges. The other corrected spherical aberration, an optical effect resulting in blurred images. By the 1830s large clear images were being produced, instead of large blurry images.
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© CHIN 2001