Microscope part 1

A microscope (from the Ancient Greek: μικρός, mikrós, "small" and σκοπεῖν, skopeîn, "to look" or "see") is an instrument used to see objects that are too small for the naked eye. The science of investigating small objects using such an instrument is called microscopy. Microscopic means invisible to the eye unless aided by a microscope.

Function of Microscope:

The function of a microscope is to enlarge the visual image of small objects (a telescope, on the other hand, is enlarges the image of distant objects). More specifically, microscopes enlarge the image of objects too small to be seen by the naked eye.

Types of Microscopes

Microscopes need illumination to work. Depending on the source of illumination, these instruments can be divided into two broad categories. They are:

Compound Microscope:
The compound microscope uses light for illumination. Some simple compound microscopes make use of natural light whereas some have an illuminator attached to the base of the microscope that acts as the source of light. The specimen is placed on the stage and observed through different lenses of the microscope, which have varying magnification powers. Dissection microscopes and compound microscopes are a part of this category.

Electron Microscope

As the name suggests, electron microscopes focus electron beams upon the specimen instead of using light. The use of electron helps in viewing the specimen at an extremely high resolution. The camera present within the microscope captures these images to reveal the finer details of the specimen. This microscope can zoom and view the density of a specimen until it is only a micrometer thick and has a magnification ranging between 1,000 - 250,000x on the fluorescent screen. This type of microscope requires a computer software in order to function accurately and yield precise results. These microscopes provide better magnification than the light microscopes.

Two major variants of electron microscopes exist:

• Scanning electron microscope (SEM): looks at the surface of bulk objects by scanning the surface with a fine electron beam.
• Transmission electron microscope (TEM): passes electrons through the sample, analogous to basic optical microscopy. This requires careful sample preparation, since electrons are scattered so strongly by most materials.This is a scientific device that allows people to see objects that could normally not be seen by the naked or unaided eye.