Which fluid is most commonly used in pneumatics?

The most commonly used fluid in pneumatics is air. This is primarily due to its abundance, cost-effectiveness, and safety. Air is readily available in the environment, which makes it an ideal choice for various pneumatic applications, ranging from industrial machinery to simple tools.

The use of air allows for the generation of force and movement through the compression and expansion of gas, which is central to pneumatic systems. Air is also non-toxic and poses minimal health risks compared to other fluids. Furthermore, compressed air systems can be easily integrated into existing infrastructure, and the technology to generate, control, and utilize compressed air is well-developed and widely implemented.

Comparatively, other options such as oxygen, water, and oil are either not suited for typical pneumatic systems due to their properties or are used in specific niche applications. For example, while oxygen is vital in certain processes, it presents flammability risks and is not as widely used as a pneumatic medium. Water, while effective in hydraulic systems, does not compress like air and thus is not suitable in pneumatic applications. Oil may be used in specific pneumatic tools for lubrication but is not the primary medium for pneumatic operation.