Smoked glass is

glass Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling ( quenching ...

held in the

smoke Smoke is a suspension of airborne particulates and gases emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwanted by-produc ...

of a

candle A candle is an ignitable wick embedded in wax, or another flammable solid substance such as tallow, that provides light, and in some cases, a fragrance. A candle can also provide heat or a method of keeping time. A person who makes candle ...

flame (or other inefficiently burning

hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...

) such that one surface of the sheet of glass is covered in a layer of smoke residue. The glass is used as a medium for recording pen traces in

scientific instrument A scientific instrument is a device or tool used for scientific purposes, including the study of both natural phenomena and theoretical research. History Historically, the definition of a scientific instrument has varied, based on usage, laws, an ...

s, and is also used to track pheromone deposition in ants The advantages of using the glass are that the recording medium is easily renewable (just re-smoke the glass), and that the trace obtained can easily be magnified by projection onto a suitable surface. A variation on this scheme is the use of smoked paper in early seismographs. The effect of smoked glass can be incorporated into glass manufacture by adding darkening materials, such that light passing through the glass is decreased in

brightness Brightness is an attribute of visual perception in which a source appears to be radiating or reflecting light. In other words, brightness is the perception elicited by the luminance of a visual target. The perception is not linear to luminan ...

. It can be used aesthetically, for example, in the manufacture of coffee tables with smoked glass tops. It can also be used in scientific instruments as a

filter Filter, filtering or filters may refer to: Science and technology Computing * Filter (higher-order function), in functional programming * Filter (software), a computer program to process a data stream * Filter (video), a software component tha ...

, as in the use of smoked glass in cross-staves and sextants, allowing operators to make

sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

sightings without damaging their

eyesight Visual perception is the ability to interpret the surrounding environment through photopic vision (daytime vision), color vision, scotopic vision (night vision), and mesopic vision (twilight vision), using light in the visible spectrum reflect ...

References

{{glass-stub Glass coating and surface modification Smoke

See also

References