14.7 psi: The Essential Guide to Atmospheric Pressure

What is Atmospheric Pressure?

Atmospheric pressure is the force exerted by the weight of the air above a given point. It is measured in pounds per square inch (psi) or kilopascals (kPa). The average atmospheric pressure at sea level is 14.7 psi or 101.3 kPa.

Why is Atmospheric Pressure Important?

Atmospheric pressure is important for a number of reasons. It:

• Keeps us alive: Atmospheric pressure is essential for human survival. The air we breathe contains oxygen, which is necessary for our cells to function. Without atmospheric pressure, the oxygen in the air would not be compressed enough to enter our lungs.
• Prevents the oceans from boiling: Atmospheric pressure prevents the oceans from boiling. The boiling point of water decreases as the pressure decreases. At sea level, the boiling point of water is 212 degrees Fahrenheit (100 degrees Celsius). However, at the top of Mount Everest, where the atmospheric pressure is much lower, the boiling point of water is only 180 degrees Fahrenheit (82 degrees Celsius).
• Affects weather patterns: Atmospheric pressure is a major factor in weather patterns. High-pressure systems are associated with clear weather, while low-pressure systems are associated with storms.

How is Atmospheric Pressure Measured?

Atmospheric pressure is measured using a barometer. A barometer is a device that measures the weight of the air above it. There are two main types of barometers:

• Mercury barometers: Mercury barometers are the most accurate type of barometer. They consist of a glass tube filled with mercury. The weight of the mercury in the tube is balanced by the weight of the air above the tube.
• Aneroid barometers: Aneroid barometers are less accurate than mercury barometers, but they are more portable. They consist of a metal box with a diaphragm inside. The diaphragm is made of a material that expands and contracts with changes in atmospheric pressure.

Factors that Affect Atmospheric Pressure

Atmospheric pressure is affected by a number of factors, including:

• Altitude: Atmospheric pressure decreases as altitude increases. This is because there is less air above a given point at higher altitudes.
• Temperature: Atmospheric pressure decreases as temperature increases. This is because warm air is less dense than cold air.
• Wind: Wind can affect atmospheric pressure. High winds can cause atmospheric pressure to drop.

Applications of Atmospheric Pressure

Atmospheric pressure has a number of applications, including:

• Weather forecasting: Atmospheric pressure is used to forecast the weather. High-pressure systems are associated with clear weather, while low-pressure systems are associated with storms.
• Altimetry: Atmospheric pressure is used to measure altitude. Altimeters are devices that measure the height of an object above sea level.
• Medicine: Atmospheric pressure is used in a number of medical applications, such as:
  • Pulmonary function testing: Atmospheric pressure is used to test lung function.
  • Hyperbaric oxygen therapy: Hyperbaric oxygen therapy is a treatment in which patients are exposed to high levels of oxygen in a pressurized chamber.

Table 1: Average Atmospheric Pressure at Different Altitudes

Table 2: Boiling Point of Water at Different Atmospheric Pressures

Table 3: Effects of Atmospheric Pressure on Weather

Table 4: Applications of Atmospheric Pressure

Conclusion

Atmospheric pressure is a fundamental force that affects a wide range of phenomena on Earth. It is important for human survival, prevents the oceans from boiling, and affects weather patterns. Atmospheric pressure is also used in a number of applications, such as weather forecasting, altimetry, and medicine.