The Pitot Tube - Measuring Air Speed with a Manometer

A U-shaped tube, filled with a red liquid has both ends connected to rubber tubes that are open to the atmosphere. The end of one rubber tube is placed by a blower. The liquid level on the side connected to the tube rises. This can be understood by application of Bernoulli's principle which states that sum of the atmospheric pressure and the dynamic pressure (1/2 p v^2 term) is constant. Since the dynamic pressure increased when the blower caused air to flow by the tube, the atmospheric pressure on the other end caused the liquid level to rise.