1. What is the Barometric 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 formula:

Where:

• \( P \) — Pressure at altitude (Pa)
• \( P_0 \) — Reference pressure at sea level (Pa)
• \( g \) — Gravitational acceleration (m/s²)
• \( h \) — Altitude above reference (m)
• \( R \) — Specific gas constant for dry air (J/(kg·K))
• \( T \) — Absolute temperature (K)

Explanation: The formula assumes an isothermal atmosphere (constant temperature) and neglects variations in gravity with altitude.

3. Importance of Pressure Calculation

Details: Accurate pressure estimation is crucial for aviation, meteorology, engineering, and scientific research at various altitudes.

4. Using the Calculator

Tips: Enter reference pressure (default is sea level: 101325 Pa), gravitational acceleration (default is Earth: 9.80665 m/s²), altitude, gas constant (default for dry air: 287.058 J/(kg·K)), and temperature in Kelvin.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this formula?
A: It provides reasonable estimates for moderate altitudes but becomes less accurate for extreme altitudes where temperature varies significantly.

Q2: What are typical values for Earth?
A: Standard sea level pressure is 101325 Pa, g = 9.80665 m/s², R = 287.058 J/(kg·K), and standard temperature is 288.15 K (15°C).

Q3: Can this be used for other planets?
A: Yes, with appropriate values for P₀, g, and R for the specific planetary atmosphere.

Q4: What are the limitations?
A: Assumes isothermal conditions and doesn't account for humidity or temperature variations with altitude.

Q5: How does pressure change with altitude?
A: Pressure decreases exponentially with altitude, approximately halving every 5.5 km near Earth's surface.