Vehicle horn horn. Bicycles often have a classic "bulb horn", operated by squeezing a rubber bulb attached to a metal horn. Squeezing the bulb forces air through a steel reed located in the throat of the horn, making it vibrate, producing a single note. The flaring horn matches the acoustic impedance of the reed to the open air, radiating the sound waves efficiently, making the sound louder. Other types of horns used on bicycles include battery-operated horns (sometimes even car horns on 12-volt circuits are incorporated) and small air horns powered by a small can of compressed gas. Oliver Lucas of Birmingham,
Horn effect (for the observer) an unfavorable aspect of this person. Horn effect The horn effect, closely related to the halo effect, is a form of cognitive bias that causes one's perception of another to be unduly influenced by a single negative trait. An example of the horn effect may be that an observer is more likely to assume a physically unattractive person is morally inferior to an attractive person, despite the lack of relationship between morality and physical appearance. The term is derived from the English word "horn" and refers to the devil's horns. This is in contrast to the word