Short answers, pulled from the story.
Barney Walberg of the drum accessory company Walberg and Auge invented the modern hi-hat around 1926. This innovation introduced a mechanism where the upper cymbal could be raised and lowered by a foot pedal while still allowing for hand playing.
The standard size of hi-hat cymbals ranges from 14 to 15 inches in diameter. Some heavy bells extend up to 16 inches wide, creating a distinct sonic signature that defines the sound of jazz, rock, and pop.
Papa Jo Jones shifted the focus of timekeeping from the bass drum to the hi-hat to provide a swing-pulse focus. He was the first recognized master of the instrument and the first to use brushes on drums, establishing a legacy that influenced generations of musicians.
Closed hi-hat notes occur when the two cymbals are pressed together to produce a sharp chck or chick sound. Open hi-hat notes happen when the pedal is not pressed and the cymbals are apart, creating a shimmering effect that can range from a quiet wash to a loud crash.
The early versions of the hi-hat were known as clangers, which were small cymbals mounted directly onto the rim of a bass drum. Other iterations included shoes, which were two hinged boards with cymbals on the ends that were clashed together.