What is vacuum and overview of vacuum

A vacuum is defined as a diluted gas, or the corresponding state where its pressure or density is lower than that of the ambient surrounding atmosphere (atm). Because atmospheric pressure fluctuates locally over the Earth's surface and lessens as altitude above sea level increases, it isn't possible to specify a general upper limit for the vacuum range.

Overview of vacuum :

Therefore, to get a vacuum it is needed to generate a pressure in a vessel that is lower than the ambient pressure. Because of the Earth's gravity, atmospheric pressure varies with altitude in accordance with the barometric altitude formula:

Formula of 1-1: (Barometer formula)

In which:
                        g (Earth acceleration) = 9.81 m/s²

                                ρ₀ (Density of air at sea level at 0 °C) = 1.293 kg/m³

                        p₀  (Atmospheric pressure at sea level ) = 1,013 mbar

Combining the constants yields:

Formula of 1-1: (Barometer formula)

IF p = p₀ / 2 and the formula is solved for h, the result is the half altitude value h_½= 5,548 m. To put it differently : Atmospheric pressure declines by one half every 5.548 km.

At the cruising altitude of a passenger jet, i.e. at approximately 10 km above the surface of the Earth, atmospheric pressure has already decreased to 290 mbar. Weather balloon data are measured at an altitude of approximately 30 km at a pressure of 24 mbar. The pressure levels prevailing at these altitudes can still be categorized as being in the low vacuum range, which will be discussed in greater detail below. An even greater distance from the Earth‘s surface, finally, brings us to satellite orbits at an altitude of 250 km, where the pressure has now decreased to 10^-5 to 10^-6. What prevails farther out in space is an ultra high vacuum of less than 10^-14

.

Practical utilization of pressure differentials to exert a force is meaningful in the 1,000 to

1mbar range. In this application range, vacuum is indicated in % of atmospheric pressure.Various aids are required in order to achieve pressures on Earth that are similar to the natural vacuum that prevails in space. These differing pressure ranges can be achieved through the use of vacuum pumps.