Microscope

Microscopes have been around for over four hundred years. Historians are not positive who invented the microscope. Credit has been given to Hans Lippershey, Hans Janssen, Zacharias Janssen and Anthony Leeuwenhoek, all of Holland. The history of the microscope has been one of many discoveries. Before microscopes, no one knew about the existence of things like bacteria and other creatures so small, they are called microscopic. Among the people who helped to improve early microscopes were such great men as Galileo and Robert Hooke. Today most microscopes are manufactured in Germany, China and Japan.

There are several different types of microscope. One is the electron microscope. Electron microscopes use a beam of highly charged electrons to examine objects on a very fine scale. With an electron microscope a scientist can collect a great deal of information on a subject: its topography, morphology, composition and cystallographic information.

A scanning electron microscope has a virtual source that produces a stream of monochromatic electrons. The stream is condenses and then constricted, then formed into a thin, tight, coherent beam. The beam is then used to sweep or “scan” the sample being studied. The scanning can cover a pattern at a rate of 30 times a second.

A compound microscope is one that uses two or more lenses to magnify the image of an object. The very first microscopes were compound microscopes. A compound light microscope uses a combination of multiple lenses and a source or artificial light to magnify and illuminate an image. Modern compound light microscopes are more than a thousand times more powerful than the microscopes used in the 17th century.

A light microscope uses visible light to detect small objects. The light microscope is the most well known and most commonly used research tool in biology. The microscopes found in classrooms are usually light microscopes. The very best microscopes are too expensive for most schools.

A digital microscope is made up of a digital camera unit and a controller. It uses USB energy to produce live images on a computer monitor. The digital microscope allows for quick observation, analysis and data processing with little preparation.

The parts of a microscope depend upon the type of microscope. Basically, a microscope diagram would show the following microscope parts:
Eyepiece lens – the part you look through
Tube – connects the eyepiece lens to the objective lens
Arm – supports tube
Base – the bottom of the microscope, used for support
Illuminator – a steady source of light
Stage – flat platform where slides are placed
Revolving Nosepiece or turret– rotating part that holds objective lenses
Objective lenses – three or four lenses, usually of 4x, 10x, 40x, and 100x powers.

Condenser lens – for focusing light into the specimen

Diaphragm or Iris – rotating disc under the stage, used to vary intensity and size of cone of light projected upward into the slide.

Microscopes are delicate instruments and should be handled very carefully. Always follow instructions on how to use a microscope. Be sure to keep your microscope clean. Dust is its worst enemy.