An apparatus in which the movement and collision of ionizing particles is determined by the examination of trails of gas bubbles that form in the paths of the particles as they move through a superheated liquid. Subatomic-particle detector that uses a superheated liquid which boils into tiny bubbles of vapour along the tracks of the particles. As charged particles move through the liquid, they knock electrons from the atoms of the liquid, creating ions. If the liquid is close to its boiling point, the first bubbles form around these ions. The observable tracks can be photographed and analyzed to measure the behaviour of the charged particles. Developed in 1952 by Donald Glaser, the bubble chamber proved very useful in the 1960s and '70s for the study of high-energy nuclear and particle physics