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Excess pressure is the difference in pressure caused between the inner side of the surface and the outer side of the surface. It represents the additional pressure inside a liquid drop or bubble compared to the surrounding environment due to surface tension effects.
The calculator uses the formula:
Where:
Explanation: This formula describes the relationship between surface tension, curvature, and the resulting pressure difference across a curved liquid surface.
Details: Calculating excess pressure is crucial in understanding phenomena such as bubble formation, droplet behavior, capillary action, and various industrial processes involving fluid interfaces.
Tips: Enter specific surface energy in J/m² and radius in meters. Both values must be positive numbers greater than zero for valid calculation.
Q1: Why is there a factor of 2 in the formula?
A: The factor of 2 appears because a liquid sphere has two surfaces (inner and outer) contributing to the surface tension effect.
Q2: What are typical values for specific surface energy?
A: Specific surface energy values typically range from 0.01 to 0.1 J/m² for most common liquids at room temperature.
Q3: How does radius affect excess pressure?
A: Excess pressure is inversely proportional to radius - smaller spheres/bubbles have higher excess pressure, which is why small bubbles are more stable than large ones.
Q4: Does this formula apply to all curved surfaces?
A: This specific formula applies to spherical surfaces. For other curved surfaces, more complex formulas involving principal radii of curvature are used.
Q5: What are the practical applications of this calculation?
A: This calculation is used in various fields including chemical engineering (bubble columns), medicine (lung alveoli), materials science (foams), and meteorology (cloud droplet formation).