1. What is the Magnus Formula?

The Magnus formula is an empirical relationship between the vapor pressure of water and temperature. It provides a good approximation of the water vapor pressure over liquid water for temperatures between 0°C and 100°C.

2. How Does the Calculator Work?

The calculator uses the Magnus formula:

Where:

• \( P \) — Vapor pressure (hPa)
• \( T \) — Temperature (°C)

Explanation: The formula calculates the saturation vapor pressure of water as a function of temperature, with 6.1078 hPa being the vapor pressure at 0°C.

3. Importance of Vapor Pressure Calculation

Details: Water vapor pressure is crucial in meteorology, HVAC design, industrial processes, and understanding humidity and evaporation rates.

4. Using the Calculator

Tips: Enter temperature in Celsius. The formula is valid for temperatures between 0°C and 100°C.

5. Frequently Asked Questions (FAQ)

Q1: What is the range of validity for the Magnus formula?
A: The formula is most accurate between 0°C and 100°C, though it can provide rough estimates beyond this range.

Q2: How does vapor pressure relate to humidity?
A: Relative humidity is the ratio of actual vapor pressure to saturation vapor pressure at that temperature.

Q3: Why is 6.1078 used in the formula?
A: This is the vapor pressure of water at 0°C (triple point of water) in hectopascals.

Q4: Are there more accurate formulas?
A: Yes, the August-Roche-Magnus formula and Goff-Gratch equation provide more precise results in different conditions.

Q5: How does altitude affect vapor pressure?
A: Vapor pressure decreases with altitude due to lower atmospheric pressure, though the relationship is complex.