Explanation:
A Bourdon gauge is a mechanical instrument used to measure pressure, typically in industrial settings. It works by measuring the force exerted by a fluid on a flexible metal tube, called a Bourdon tube. The tube is curved in a C shape and sealed at one end. The other end is connected to the pressure source, and as the pressure increases, the tube straightens out slightly, which is then converted into a reading on the gauge.

Gauge Pressure:
The Bourdon gauge measures gauge pressure, which is the pressure above atmospheric pressure. Gauge pressure is the most common type of pressure measurement used in industrial settings, as it is often more useful to know the difference between the pressure of a fluid and the pressure of the surrounding atmosphere than the absolute pressure of the fluid.

Local Atmospheric Pressure:
Although the Bourdon gauge does not measure local atmospheric pressure, it can be used to measure the difference between local atmospheric pressure and gauge pressure. By calibrating the gauge at a known atmospheric pressure, it is possible to determine the local atmospheric pressure by subtracting the gauge pressure from the known atmospheric pressure.

Absolute Pressure:
Absolute pressure is a measure of the total pressure exerted by a fluid, including atmospheric pressure. The Bourdon gauge does not measure absolute pressure, as it is designed to measure only the pressure above atmospheric pressure.

Standard Atmospheric Pressure:
Standard atmospheric pressure is the pressure exerted by the Earth's atmosphere at sea level, which is typically around 101.3 kilopascals (kPa). The Bourdon gauge does not measure standard atmospheric pressure, as it is designed to measure only the pressure above atmospheric pressure.