microscopes

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Celestron Dissecting Microscope

Microscope  is an instrument for viewing objects that are too small to be seen by the naked or unaided eye. The term microscopic means minute or very small, not visible  with the eye unless aided by a microscope. The most common type of microscopeis the optical microscope.containing one or more lenses that produce an enlarged image of an object placed in the focal plane of the lens(es). Optical microscopes, through their use of visible wavelengths of light, are the simplest and hence most widely used type of microscope. The device use refractive lenses, typically of glass and occasionally of plastic, to focus light into the eye or another light detector. Typical magnification of a light microscope is up to 1500x with a theoretical resolution of around 0.2 micrometres or 200 nanometers.

optical theory microscopes, electron microscopes and scanning probe microscopes.

Optical theory microscopes are microscopes which function through the optical theory of lenses in order to magnify the image generated by the passage of a wave through the sample. The waves used are either electromagnetic in optical microscopes or electron beams in electron microscopes. The types are the Compound Light, Stereo, and the electron microscope.

Electron microscopes
Electron microscopes, which use beams of electrons instead of light, are designed for very high magnification usage. Electrons, which can be accelerated to produce a much smaller wavelength than visible light, allow a much higher resolution.

Two major variants of electron microscopes are the Scanning electron microscope: used for spectroscopy.and  Transmission electron microscope: used to obtain detailed information on the sample's crystallography through selected area diffraction

Other microscopes
Other microscopes which use electromagnetic wavelengths not visible to the human eye are often called optical microscopes. The most common of these, due to its high resolution yet no requirement for a vacuum like electron microscopes, is the x-ray microscope.
Scanning acoustic microscopes use sound waves to measure variations in acoustic impedance. Similar to Sonar in principle, they are used for such jobs as detecting defects in the subsurfaces of materials including those found in integrated circuits.