Exercise ball Exercise ball An exercise ball, also known as a Swiss Ball, is a ball constructed of soft elastic with a diameter of approximately 35 to 85 centimeters (14 to 34 inches) and filled with air. The air pressure is changed by removing a valve stem and either filling with air or letting the ball deflate. It is most often used in physical therapy, athletic training and exercise. It can also be used for weight training. The ball, while often referred to as a Swiss ball, is also known by a number of different names, including balance ball, birth ball, body
The Billiard Ball The Billiard Ball "The Billiard Ball" is a science fiction short story by American author Isaac Asimov, written in September 1966 and first published in the March 1967 issue of "If". It appeared in Asimov's 1968 collection "Asimov's Mysteries", in his 1973 collection "The Best of Isaac Asimov", in his 1986 collection "Robot Dreams" and in "The Complete Stories, Vol. 2". An example of what Asimov called his "late style", the story is a journalist's recollection of the events surrounding the discovery of an anti-gravity device in the mid-21st century. Heavy with physics theory, the story describes the relationship between