How To Calculate Saturated Vapour Pressure

Saturated Vapour Pressure Equation:

\[ e_s = 6.112 \times \exp\left(\frac{17.67 \times T}{T + 243.5}\right) \]

Saturated Vapour Pressure (e_s):

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1. What is Saturated Vapour Pressure?

Saturated vapour pressure is the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases at a given temperature. It represents the maximum amount of water vapor the air can hold at a specific temperature.

2. How Does the Calculator Work?

The calculator uses the standard equation for saturated vapour pressure:

\[ e_s = 6.112 \times \exp\left(\frac{17.67 \times T}{T + 243.5}\right) \]

Where:

\( e_s \) — Saturated vapour pressure (hPa)
\( T \) — Temperature (°C)
\( \exp \) — Exponential function

Explanation: This empirical equation provides an accurate approximation of saturated vapour pressure over water for meteorological applications.

3. Importance of Saturated Vapour Pressure

Details: Saturated vapour pressure is crucial in meteorology for calculating humidity, predicting fog formation, understanding evaporation processes, and in various engineering applications involving air-water systems.

4. Using the Calculator

Tips: Enter the temperature in degrees Celsius. The calculator will compute the saturated vapour pressure in hectopascals (hPa).

5. Frequently Asked Questions (FAQ)

Q1: What is the relationship between temperature and saturated vapour pressure?
A: Saturated vapour pressure increases exponentially with temperature. Warmer air can hold significantly more water vapor than colder air.

Q2: How is this different from actual vapour pressure?
A: Saturated vapour pressure is the maximum possible vapour pressure at a given temperature, while actual vapour pressure is the amount of water vapor currently present in the air.

Q3: What are typical values of saturated vapour pressure?
A: At 0°C, it's about 6.11 hPa; at 20°C, about 23.39 hPa; and at 40°C, about 73.78 hPa.

Q4: Why is this important for weather forecasting?
A: It helps determine relative humidity, dew point, and is essential for predicting precipitation, fog, and other weather phenomena.

Q5: Are there different equations for different substances?
A: Yes, different substances have different vapour pressure curves. This equation is specifically for water vapor over liquid water.