Scientists And Discoveries

The History of the Microscope



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The ability to extend our natural visual range to include observation of the very small was quite a late arrival as fundamental inventions go. It was not until around 1595 in Middelberg, Holland, that the first compound microscope, which made use of two lenses, was invented. The inventors were the Dutch brothers Hans and Zacharias Janssen, who were spectacle makers by profession. However, these early microscopes were of limited use. They provided only blurred images because of the imperfections that were present in the lenses.

A major breakthrough occurred in 1674 when the Dutch scientist Anton Van Leeuwenhoek produced a perfectly ground single lens. He used this to observe a whole host of what came to be known as microscopic entities. These included bacteria and single-celled organisms that he called animalcules. He was even able to use it to observe human spermatozoa for the first time. This was to prove one of the most important advances in scientific history, with a whole new world opened up to biologists for them to study.

But this was to be the beginning of a long, slow process of improving microscope technology and it was only in the 19th Century that it was perfected enough to observe cell structure. This proved to be another important watershed in the understanding of biological organisms. But these early microscopes were all optical microscopes. They all used a specially ground lens, usually made of glass, although possibly of plastic or quartz, to enlarge the image of an object that is placed in the focal plane.

The twentieth century saw the arrival of several new types of microscope design. One of these was the electron microscope. This design is many times more powerful in magnification than an ordinary optical microscope. Electron microscopes work by using a magnetic field to focus an electron beam on a target. Three main variations on the electron microscope have been developed. These are the scanning electron microscope, the transmission electron microscope, and the scanning tunnelling microscope.

Another important design that was developed during the twentieth century was the scanning probe microscope. These work on the basis of physically sending a probe across the surface of the object and recording the interaction between the probe and the surface using a raster scan. There are many different version of scanning probe microscope such as the atomic force microscope, for example. With the increasing perfection of new microscope technology in recent decades, microscopy has allowed not only biologists to improve their understanding, but also chemists and physicists have been able to observe the very structure of matter itself.

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