1. What is Surface Tension?

Surface tension (γ) is the energy required to increase the surface area of a liquid by a unit amount. In soil science, it's crucial for understanding water movement and retention in soil pores.

2. How Does the Calculator Work?

The calculator uses the surface tension equation:

Where:

• \( \gamma \) — Surface tension (N/m)
• \( F \) — Force acting on the surface (N)
• \( L \) — Length along which the force acts (m)

Explanation: The equation calculates the force per unit length acting at the interface between soil water and air.

3. Importance in Soil Science

Details: Surface tension affects capillary action, water retention, and hydraulic conductivity in soils. It's fundamental for understanding water movement in unsaturated zones.

4. Using the Calculator

Tips: Enter force in newtons (N) and length in meters (m). Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is typical surface tension for soil water?
A: Pure water at 20°C has γ ≈ 0.0728 N/m. Soil water values vary with temperature and solute content.

Q2: How does temperature affect surface tension?
A: Surface tension decreases with increasing temperature due to reduced intermolecular forces.

Q3: Why is surface tension important for plants?
A: It influences water availability in soil pores and the energy plants must expend to extract water.

Q4: How do surfactants affect surface tension?
A: Surfactants (like those in detergents) can significantly reduce surface tension, altering water movement in soils.

Q5: Can this calculator be used for other liquids?
A: Yes, the same equation applies to any liquid, though the actual surface tension values will differ.