What is an example of a manometer equation?

Manometers are relatively simple pressure gauges. An example of the kind of equation that uses data from a manometer is one employed to calculate the pressure difference between ambient fluid, such as air at sea level, and low-pressure air inside a wind tunnel.

For this equation, the manometer, which is simply a U-shaped tube with fluid inside of it, is filled with water. Water has a known density of 1 kg per liter. External air pressure is 1 atm. If the water rises in one side of the manometer by 10 cm, the difference between the two points is 0.00968 atm.