The Evolution of the Light and Electron Microscope

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Birth of the Light Microscope In Circa 1000AD the first vision aid was invented (the inventor is unknown) it was called a reading stone. It was described as a glass sphere that magnified reading material when placed on top of an object. Someone picked up a piece of transparent crystal thick in the middle than at the edges, they looked through it, and realized it made objects look bigger. “Magnifying glasses” are mentioned during the first century A.D by Roman philosophers Seneca and Pliny the Elder, but never used much until the invention of spectacles, at the end of the 13th century. The earliest microscope was a simple tube with a plate at one end and a lens at the other, which magnified less than ten times its actual size. They were used to view fleas and tiny creepy things and were then dubbed “flea glasses”. In Circa 1284 the first wearable eye glasses where invented and credited to Italian, Salvino D’Amate. In about 1590, two Dutch spectacle makers, Zaccharias Janssen and his son Hans discovered while experimenting with the tubes realized that objects appeared greatly enlarged, which ended up the forerunner of the compound microscope and the telescope. In 1609 Galileo, father of modern physics and astronomy, heard of these experiments and figured out the workings of the lenses and made a better device with the ability to focus. Robert Hooke (1635 - 1703) Robert Hooke is thought as one of the most neglected natural philosophers of all time. He of amongst other things, the originator of the word ‘cell’ in biology. English physicist looked at a silver of cork through a microscope lens and noticed some “pores” or “cells” in it. He believed the cells had served as containers for the “noble juices” or “fibrou... ... middle of paper ... ...In this microscope the electrons are speeded up in a vacuum until the wavelength is only one hundred thousandth that of white light. The beams of these fast moving electrons are focused on a cell sample and are absorbed or scattered by the cell’s parts to form an image on an electron sensitive photographic plate. The electron microscope can magnify objects up to 1 million times. Nevertheless, the electron microscope does suffer from a serious setback, no living specimen can survive under its high vacuum, and they cannot show the changing movements that characterize a living cell. References and citing’s by Mary Bellis – accessed 25 Jan 2013

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