1. What is the Barometric Pressure Formula?

The barometric formula describes how atmospheric pressure decreases with altitude in an isothermal atmosphere. It's derived from the ideal gas law and hydrostatic equilibrium.

2. How Does the Calculator Work?

The calculator uses the barometric pressure equation:

Where:

• \( P \) — Pressure at altitude (Pa)
• \( P_0 \) — Sea level pressure (101325 Pa)
• \( M \) — Molar mass of air (0.02896 kg/mol)
• \( g \) — Gravitational acceleration (9.8 m/s²)
• \( h \) — Altitude (meters)
• \( R \) — Universal gas constant (8.314 J/(mol·K))
• \( T \) — Temperature (Kelvin)

Explanation: The formula shows how pressure decreases exponentially with altitude, with the rate of decrease depending on temperature and air composition.

3. Importance of Barometric Pressure

Details: Barometric pressure calculations are essential for aviation, meteorology, altitude sickness prediction, and various engineering applications.

4. Using the Calculator

Tips: Enter sea level pressure (default is standard 101325 Pa), molar mass of air (default 0.02896 kg/mol for dry air), altitude in meters, and temperature in Kelvin.

5. Frequently Asked Questions (FAQ)

Q1: Why does pressure decrease with altitude?
A: Pressure decreases because there's less air above pushing down as you go higher in the atmosphere.

Q2: What's the standard sea level pressure?
A: Standard atmospheric pressure at sea level is 101325 Pa (1013.25 hPa or 1 atm).

Q3: How does temperature affect the calculation?
A: Higher temperatures result in slower pressure decrease with altitude because warmer air is less dense.

Q4: What's the molar mass of air?
A: For dry air it's approximately 0.02896 kg/mol. For humid air it's slightly less because water molecules are lighter than nitrogen and oxygen.

Q5: Is this formula accurate for all altitudes?
A: It works best for lower altitudes (troposphere). For higher altitudes, more complex models are needed due to temperature variations.