a state of matter in which the shape of the given mass depends on the containing vessel, but the volume of the mass is independent of the vessel. A liquid is a practically incompressible fluid. liquid-level controller any device used to control the liquid level in a tank by actuating electric or pneumatic switches that open and close the discharge valve or the intake valve, thus maintaining the liquid at the desired level.
Surface Acoustical Holography- form of holography technique in which the workpiece and two ultrasonic transducers are immersed in a water-filled tank and the ripples in the tank are then used to create the holographic image
