1. What is a Vapor Pressure of Water Calculator?

Definition: This calculator estimates the vapor pressure of water based on air temperature using the Magnus formula.

Purpose: It helps meteorologists, engineers, and scientists determine the equilibrium vapor pressure of water at a given temperature.

2. How Does the Calculator Work?

The calculator uses the Magnus formula:

Where:

• \( P \) — Vapor pressure (hPa)
• \( T \) — Temperature (°C)
• \( e \) — Euler's number (~2.71828)

Explanation: The formula approximates the relationship between temperature and the saturation vapor pressure of water.

3. Importance of Vapor Pressure Calculation

Details: Vapor pressure is crucial for understanding humidity, evaporation rates, and atmospheric processes. It's used in weather forecasting, HVAC design, and industrial processes.

4. Using the Calculator

Tips: Enter the temperature in Celsius. The valid range is typically between -40°C and +50°C for most practical applications.

5. Frequently Asked Questions (FAQ)

Q1: What is vapor pressure?
A: Vapor pressure is the pressure exerted by water vapor in equilibrium with liquid water at a given temperature.

Q2: Why does vapor pressure increase with temperature?
A: Higher temperatures provide more energy for water molecules to escape from the liquid phase into the vapor phase.

Q3: What are typical vapor pressure values?
A: At 0°C: ~6.11 hPa, at 20°C: ~23.39 hPa, at 100°C: ~1013.25 hPa (standard atmospheric pressure).

Q4: How accurate is the Magnus formula?
A: It's accurate to within 0.1% for temperatures between -30°C and +35°C compared to more complex equations.

Q5: Can this be used for ice/snow?
A: No, this formula is for liquid water. Different equations exist for the vapor pressure over ice.