Boyle's law describes the relationship between pressure and volume of a gas when the temperature is held constant. It is named after Robert Boyle of Ireland who published it in 1662. Two of Boyle's friends who were amateur scientists (Henry Power and Richard Towneley) discovered that the pressure and volume of a gas are inversely proportionate. Boyle's two friends brought this information to his attention, He and his assistant, Robert Hooke, began a scientific study of the pressure and volume of air, confirming this relationship.

If the volume of a gas increases while temperature is held constant, what happens to the pressure?