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Nedeľa, 14. apríla 2024
Dátum pridania: 21.07.2010 Oznámkuj: 12345
Autor referátu: 24MoNi24
Jazyk: Angličtina Počet slov: 824
Referát vhodný pre: Gymnázium Počet A4: 2.7
Priemerná známka: 2.98 Rýchle čítanie: 4m 30s
Pomalé čítanie: 6m 45s


A microscope is an instrument for viewing objects that are too small to be seen by eye. The science of investigating small objects using such an instrument is called microscopy. The term microscopic means minute or very small, not visible with the eye unless aided by a microscope.



Microscopes began their history almost 1200 years ago, with Abbas Ibn Firnas' corrective lenses, and it was Ibn al-Haytham's Book of Optics — written between 1011 and 1021 — that gave the foundation for optical research on the magnifying glass. Also, a invention called the reading stone by an unknown inventor (thought to be Ibn Firnas) magnified text when gave on top of reading materials. The first true microscope was made around 1595 in Middelburg, Holland. Three different eyeglass makers have been given credit for the invention: Hans Lippershey (who also developed the first real telescope); Hans Janssen; and his son, Zacharias. The coining of the name "microscope" has been credited to Giovanni Faber, who gave that name to Galileo Galilei's compound microscope in 1625.



"Microscopes" can largely be separated into three classes: optical theory microscopes (Light microscope), electron microscopes (e.g.,TEM), and scanning probe microscopes (SPM). The most common type of microscope—and the first to be invented—is the optical microscope. This is an optical instrument containing one or more lenses that produce an enlarged image of an object placed in the main plane of the lenses. The types are the Compound Light, Stereo, and the electron microscope.
Scanning acoustic microscopes use sound waves to determine variations in acoustic impedance. Similar to Sonar in principle, they are used for such jobs as find out defects in the subsurfaces of materials including those found in integrated circuits.


The basic parts of the microscope

The use of microscopes lets us see an invisible world that could bring delight and amazement. In the laboratory, it is necessary for student explorers to be able to use a microscope in order for them to aware the microscopic world of science. We know for a fact that a microscope can help us see things out of our eyesight, but what are the basic parts of a microscope that enable us to do so? For a basic microscope that you usually see in school laboratories, there are several parts that make the invention work. Take a look at the following list to recognize them and get some information about their respective functions.

Eyepiece - This is the part where you will look through so that you can see the magnified image. It has a lens with a power of magnification of about 10X. Tube-This part connects the Eyepiece to the Objective glass lenses.

Objective Lenses - In most microscopes, you will be able to identify about three to four objective lenses belonged at the end of the Tube; the most common rate of these lenses range from 4X to 100X magnifying powers. As a standard, the longest objective lens provides greater magnifying power while the shortest provides the minimum. Turret-The “dish” that provides support for all the Objective lenses. This dish can be rotated to allow the user to change power magnifications.

Arm - This is the metallic curved part of the microscope which connects the Tube to the Base of the invention.

Base - It is the bottom part of the invention which makes the microscope stable. It looks like horseshoe in appearance.

Illuminator - Modern microscopes can use this invention which provides a light source to illuminate the sample in the glass. Other previously manufactured devices provide a type of reflecting glass which gets light from outer sources.

Stage - It is the area where you will place the sample (on a glass slide) for observation.



Zacharias Jansen (1580 - 1638) was a Dutch spectacle-maker from Middelburg credited with inventing, or contributing advances towards the invention of the telescope. Jansen is sometimes credited for inventing the first truly compound microscope. However, the origin of the microscope - just like the origin of the telescope - is a matter of debate. Jansen was born in The Hague in 1580. He grew up with his sister Sara in Middelburg and became a spectacle-maker. By choosing this profession, he became the direct competitor of Lippershey, who practically lived next door. The fact that they lived this close to one another would play a great role in the investigations on the invention of the telescope. Jansen invented the microscope, probably with the help of his father, in 1595 while he was trying to find a way to make magnification even greater, to help people with seriously poor eyesight. In The Hague, he had his first marriage with Catharina de Haene. In 1612 was born their son Johannes Sachariassen. He would later testify under promise that Johannes Lippershey had stolen his father's invention of the telescope.
Following the death of Jansen's first wife in 1624, he married Anna Couget from Antwerp, who was the widow of some Willem Jansen (probably a family member of Jansen). He moved to Amsterdam in November 1626. He died about 1632.

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