ultramicroscope, dark-field microscope(noun)
light microscope that uses scattered light to show particles too small to see with ordinary microscopes
a microscope that uses bright illumination against a black background to view small particles
An ultramicroscope is a system of illumination for viewing tiny particles. When the diameter of a particle is below or near the wavelength of light, the particle cannot be seen in a light microscope with the usual method of illumination. The ultramicroscope system is based on light scattering, not light reflection. In the system, the particles to be observed are dispersed in a liquid or gas colloid. The colloid is placed in a light-absorbing, dark enclosure, and illuminated with a convergent beam of intense light entering from one side. Light hitting the colloid particles will get scattered. In discussions about light scattering, the converging beam is called a "Tyndall cone". The scene is viewed through an ordinary microscope placed at right angles to the direction of the lightbeam. Under the microscope, the individual particles will appear as small fuzzy spots of light moving irregularly. The spots are inherently fuzzy because light scattering produces fuzzier images than light reflection. The particles are in Brownian motion in most kinds of liquid and gas colloids, which causes the movement of the spots. The ultramicroscope system can also be used to observe tiny nontransparent particles dispersed in a transparent solid or gel.
The numerical value of ultramicroscope in Chaldean Numerology is: 5
The numerical value of ultramicroscope in Pythagorean Numerology is: 8
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"ultramicroscope." Definitions.net. STANDS4 LLC, 2017. Web. 25 May 2017. <http://www.definitions.net/definition/ultramicroscope>.