You might be most familiar with sonography's role in the field of obstetrics to produce an ultrasound image of an unborn baby. Sonography is also used to analyze tissues and organs of the body, such as the heart, eyes and abdomen.
Etymology: Pierre S. de Laplace, French physicist, 1749-1827. a principle of physics that the tension on the wall of a sphere is the product of the pressure times the radius of the chamber and the tension is inversely related to the thickness of the wall.
Charles' law is also known as the law of volumes, with an equation indicating that volume divided by temperature equals the constant. This equation is easier to determine if a gas is maintained at a constant pressure and the constant changes only by the increase or decrease in temperature.