microscopes

Microscopes – Help Scientists Explore Hidden Worlds

The microscope is an invaluable tool in today's research and education. It is used in a wide range of scientific fields, where major discoveries in biology, medicine and materials research are based on advances in microscopy.

From the simple light microscope different techniques have evolved, aimed at making it possible to see certain objects or processes. Scientists use electron microscopes in order to get extraordinary resolution, microscopes that give three-dimensional images of surfaces or biological molecules, and microscopes that mark out specific substances.

From Thrilling Toy to Important Tool

the microscope has unveiled the secrets of nature. The human eye has a resolution in the order of 100 um (10-4 m), which is about the thickness of a hair. With the microscope, whole worlds become available, filled with knowledge that can serve as inspiration to our fantasy. The exploration of microcosmos has led to numerous discoveries, without which we would be left with the limited knowledge our eyes give us.

The development of the conventional microscope at the end of the 16th century would lead to a great step forward for science, particularly in biology and medicine. In the beginning though, the microscope was mainly a toy in rich homes. But many important discoveries followed. The first scientific results based on microscopy dealt with the circulating blood system and changed our view of the human body. Scientists have also discovered and explored life's own building block – the cell. Different types of bacteria and the following struggle against diseases, as well as studies of different materials and their qualities are other valuable results.

Through ingenious inventions, the limit of what scientists could reveal from the hidden expanded continuously during the seventeenth and eighteenth centuries. Finally, at the end of the nineteenth century physical limits in the form of the wavelength of light stopped the quest to see further into the microcosmos. With the theories of quantum physics, new possibilities appeared – the electron with its extremely short wavelength could be used as "light-source" in microscopes with unprecedented resolution. The first prototype of the electron microscope was constructed around 1930. In the following decades, smaller and smaller things could be studied. Viruses were identified and with magnifications up to one million, even atoms finally became visible.

Since photography has developed hand in hand with different techniques of microscopy, the public has been able to follow close in the footsteps of scientists. Pictures of cell division, nerves that make up the brain and single atoms have changed our view of the human body and nature itself. Even today our ability to lurk into nature increases further, owing to new techniques of microscopy for studying delicate processes within the cell or the building of materials atom by atom with nanotechnology.

Time Line
14th century – The art of grinding lenses is developed in Italy and spectacles are made to improve eyesight.

1590 – Dutch lens grinders Hans and Zacharias Janssen make the first microscope by placing two lenses in a tube.

1667 – Robert Hooke studies various object with his microscope and publishes his results in Micrographia. Among his work were a description of cork and its ability to float in water.

1675 – Anton van Leeuwenhoek uses a simple microscope with only one lens to look at blood, insects and many other objects. He was first to describe cells and bacteria, seen through his very small microscopes with, for his time, extremely good lenses.

18th century – Several technical innovations make microscopes better and easier to handle, which leads to microscopy becoming more and more popular among scientists. An important discovery is that lenses combining two types of glass could reduce the chromatic effect, with its disturbing halos resulting from differences in refraction of light.

1830 – Joseph Jackson Lister reduces the problem with spherical aberration by showing that several weak lenses used together at certain distances gave good magnification without blurring the image.

1878 – Ernst Abbe formulates a mathematical theory correlating resolution to the wavelength of light. Abbes formula make calculations of maximum resolution in microscopes possible.

1903 – Richard Zsigmondy develops the ultramicroscope and is able to study objects below the wavelength of light.

1932 – Frits Zernike invents the phase-contrast microscope that allows the study of colorless and transparent biological materials.

1938 – Ernst Ruska develops the electron microscope. The ability to use electrons in microscopy greatly improves the resolution and greatly expands the borders of exploration.

1981 – Gerd Binnig and Heinrich Rohrer invent the scanning tunneling microscope that gives three-dimensional images of objects down to the atomic level.

this is my study on microscopes