What was zacharias janssen contribution to science

This contributed to the cell theory by making it easier and more practical to observe cells. The theory states that all cells arise from pre-existing cells, according to About. Zacharias Jansen, a Dutch spectacle maker, invented the first compound microscope around The first microscope was a tube with a lens in each end, mounted on a tripod. It could magnify objects five to nine times.

A modern compound microscope often has two eyepieces, or oculars, with one lens each so that you can have binocular vision. A prism at the juncture of the oculars with the body splits the image for each side. There are generally three to four objective lenses at the other end of the microscope body, allowing for magnifications between 10 and times the magnification of the ocular lenses for a total of to times magnification.

The microscope is mounted on a stand, the specimen sits on a stage and a light source illuminates the field. Ancient Romans had a rudimentary germ theory, but the history of microbiology really starts with the microscope. Using the microscope, Robert Hooke made the first observations of microscopic phenomena and Anton van Leeuwenhoek recorded single celled organisms including bacteria, protozoa and fungi.

The microscope was used to find the causative agents of plant and animal diseases. It was instrumental in discovering the variety and function of the whole invisible microscopic world. The Janssen Drawtube Microscope - As discussed above, the origin of the optical microscope is a matter of debate, but most scholars agree that the invention of the compound microscope can be credited to Zacharias Janssen in the late sixteenth century.

At that time eyeglasses were beginning to enjoy widespread use and this focused a great deal of attention on optics and lenses. The microscope illustrated in this section was built by Zacharias Janssen, probably with the help of his father Hans, in the year Visit the Molecular Expressions Website.

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