Editing Ultramicroscope (section)

==Synopsis==
In the system, the particles to be observed are dispersed in a liquid or gas [[colloid]] (or less often in a coarser [[suspension (chemistry)|suspension]]). 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 be 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.

Ultramicroscopes have been used for general observation of [[aerosols]] and [[colloids]], in studying [[Brownian motion]], in observing [[ion]]ization tracks in [[cloud chamber]]s, and in studying biological [[ultrastructure]].