A dog whistle (also known as a quiet whistle or a G alton whistle) is a type of whistle that makes a sound in the ultrasonic range. This range cannot be heard by humans, but some animals, including dogs and domestic cats, can pick up. The whistle is used in their training. It was invented in 1876 by Francis G alton and is mentioned in his book in which he describes experiments to test the range of frequencies that can be heard by various animals such as the domestic cat.
Acoustic characteristics
The upper limit of the range of human hearing is about 20 kilohertz (kHz) for children, dropping to 15-17 kHz for middle-aged adults. The upper limit of the hearing range of a dog is about 45 kHz, while that of a cat is 64 kHz with little acoustic fluctuation. It is believed that the wild ancestors of cats and dogs developed this higher range of hearing in order to hear the high frequency sounds made by their preferred prey,small rodents.
Most dog whistles are between 23 and 54 kHz, so they are above the range of human hearing, although some are tuned within the audible range.
Human Perception
To the human ear, whistling sounds like a low hissing sound. The advantage of a dog whistle is that it does not make a loud annoying noise to humans that a normal whistle would, so it can be used to train or control animals without disturbing people. Some dog training whistles have adjustable sliders to actively control the frequency produced.
Handlers may use the whistle simply to get the dog's attention or cause pain in order to change behavior.
Different kinds
In addition to light infrasonic whistles, electronic devices for dog whistles have also been invented that emit ultrasound through piezoelectric emitters. Electronic variety is sometimes paired with circuits to curb barking dogs.
Invention Story
In the mid-1800s, Sir Francis G alton faced a dilemma. He wanted to test his hearing ability at higher frequencies, but he didn't have the equipment to measure it adequately. Using some scientific ingenuity, he set out to find an object to create the sound frequencies he wanted to study.
As a result, he received a small copper tube withslit at the end, the air in which will pass through the tube, emitting an audible signal. Along the pipe, you can move a special element up or down the pipe to create different frequencies. The sliding plug was labeled so that accurate records could be recorded in the study. This device became known as the G alton whistle.
The 1883 book "Requests for the Human Faculty and Its Development" described some of the pioneering research that the inventor carried out with a whistle. The scientist and subsequent researchers used these whistles to create increasingly high-frequency tones to test subjects of study, as well as the ability of animals to hear different tones. G alton was able to determine that the normal upper limit of human hearing is around 18 kHz. He also noted that the ability to hear higher frequencies declines with age. The author reportedly enjoyed demonstrating this experience with older people.
From his early trials, he adapted a new device to test the hearing of various animals using the sound of ultrasound. He attached the whistle to a long tube with a rubber ball on the other end. G alton went to the enclosures at the zoo, used a long stick to stretch the whistle to the animal. After the whistle was played, he observed the behavior of the individuals. He also liked to walk the streets and test out what types of dogs could hear higher pitched sounds (small dogs were better at this than big ones). G alton noted that natural selection led tobetter hearing for cats.
Further development
Early comparative psychologists took the crude methods of assessing animals and refined them. G alton whistles have been used to test hearing in reptiles (Kuroda, 1923), insects (Wever & Bray, 1933), hedgehogs (Chang, 1936), bats (Galambos, 1941) and of course rats (Finger, 1941; Smith, 1941).).
Modifications
The G alton whistle was combined in psychological laboratories with acoustic instruments, tuning forks and other hearing aids. The device was manufactured with tables of vibration levels up to five digits. The whistle itself has undergone several design changes to make the sounds more accurate. The Edelman Institute, one of the manufacturers of G alton whistles, added a diaphragm to the device to prevent over-blow (Ruckmick, 1923). Early psychologists made their own design changes to fit their experiments.
At Harvard, Frank Patti invented a blower that could provide a steady, steady stream of air pressure through a whistle for an hour and a half. Despite its simplicity, whistling has been used in very complex and revealing psychological experiments. One such early experiment combined a G alton whistle and a Titchener sound cell to study differences in ear sensitivity to sound (Ferree & Collins, 1911).
Our days
From its inception in 1876, the G alton Whistle is still in use today. Being an invention of simplicity and imagination, this whistleplayed an important role in humanity's understanding of hearing.
Romance
"G alton's Whistle" is a science fiction short story by American writer L. Sprague de Camp from the Viagens Interplanetarias series. This is the first (chronologically) set on the planet Vishnu. He was first published as "Ultrasonic God" in Future Combined with Fantastic Stories in the July 1951 issue. The novel first appeared as a book under its current title (preferred author) in the Continent collection.
He has also appeared in New Science Fiction (Belmont Books, 1963), Good Old Things (Griffin St. Martin's, 1998). This story has been translated into Portuguese, Dutch and Italian.
The plot of the novel
Surveyor Adrian Frome, one of a group of three working in the jungles of the planet Vishnu, is captured by Jelly aboriginal centaur after his superior is killed and a third member of the team deserts him. Once at their base, he learns that they are taking orders from Sirat Mongkut, a tyrant previously lost in the area who pretends to be a god and has ambitions to unite the tribes under him by proclaiming himself as emperor. He uses an ultrasonic whistle to bolster his authority.
Another captive is Elena Milyan, a female missionary who also went missing. Faced with the choice of joining the kidnapper or his death, Frome pretends to support him while at the same timetrying to find a way to thwart the madman's grand plan and escape. When this happens, he kills Sirat and hides with Elena. Successfully rescued, he applies for a transfer to Ganesha, another world in the star system, in order to escape Elena in turn, as he develops a romantic connection with her and discovers that she is an incurable fanatic.
Vishnu's planet is a tropical world occupying the same star system as Krishna, de Camp's main object in the Viagens Interplanetarias series.
As written in The Continental Makers and Other Viagen Tales and in de Camp's 1959 version of The Krishna Story, G alton's Whistle is set in 2117 CE. e.
