electric spark

Electric spark

A transient form of gaseous conduction. This type of discharge is difficult to define, and no universally accepted definition exists. It can perhaps best be thought of as the transition between two more or less stable forms of gaseous conduction. For example, the transitional breakdown which occurs in the transition from a glow to an arc discharge may be thought of as a spark. See Electrical conduction in gases

Electric sparks play an important part in many physical effects. Usually these are harmful and undesirable effects, ranging from the gradual destruction of contacts in a conventional electrical switch to the large-scale havoc resulting from lightning discharges. Sometimes, however, the spark may be very useful. Examples are its function in the ignition system of an automobile, its use as an intense short-duration illumination source in high-speed photography, and its use as a source of excitation in spectroscopy. In the second case the spark may actually perform the function of the camera shutter, because its extinction renders the camera insensitive. See Spectroscopy

McGraw-Hill Concise Encyclopedia of Physics. © 2002 by The McGraw-Hill Companies, Inc.

electric spark

[i¦lek·trik ′spärk]
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in classic literature ?
At forty- seven minutes past ten Murchison will launch the electric spark on the wire which communicates with the charge of the Columbiad.
There the cartridges were arranged with the utmost regularity, connected by a metallic thread, destined to communicate to them all simultaneously the electric spark, by which means this mass of gun-cotton was eventually to be ignited.
Some flash as of an electric spark shot from Telyanin's eyes to Rostov's and back, and back again and again in an instant.
The grisette, who belonged to a class which certainly has the instinct of misery and the sufferings of the heart, suddenly felt that electric spark, darting from Heaven knows where, which can never be explained, which some strong minds deny, but the sympathetic stroke of which has been felt by many men and many women.
She was a whip-lash, a sting and a flame, an electric spark. Oh, believe me, at times there were flashes of will that scorched through her beauty and seduction and smote a victim into blank and shivering idiocy and fear.
The sight of the planet through a telescope is worth all the course on astronomy; the shock of the electric spark in the elbow, outvalues all the theories; the taste of the nitrous oxide, the firing of an artificial volcano, are better than volumes of chemistry.
While President Cleveland was waiting at Gray Gables to-day, to send the electric spark that started the machinery of the Atlanta Exposition, a Negro Moses stood before a great audience of white people and delivered an oration that marks a new epoch in the history of the South; and a body of Negro troops marched in a procession with the citizen soldiery of Georgia and Louisiana.
The sky was crossed and dotted, like the zebra's hide, with electric sparks, which danced and flickered beneath the great drops of rain.
They crisped and crackled like electric sparks. I had never heard anything like it in my life, nor could I have conceived it possible.
"Immediately ventilate the place by opening doors and windows if gas leakage, avoid switching on the exhaust fan or any other electrical equipment because leaked gas could ignite instantly from an electric spark, and ensure to install a suitable fire extinguisher and ensure its validity and functionality," he urged.
In December, two refugees were killed in a fire in Baalbek's Yammouneh after an electric spark set a tent ablaze.
Arshad Awan, one of the affected traders, told reporters that the fire broke out following an electric spark in the power transmission line passing beside the market.