Surface Tension Calculator
Calculate surface tension force using F = γ·L and pressure excess in bubbles ΔP = 4γ/r.
γ (N/m): Water 20°C=0.0728, Mercury=0.485, Ethanol=0.022, Soap solution≈0.025, Blood plasma=0.05
What Is Surface Tension Calculator?
Calculate surface tension force using F = γ·L and pressure excess in bubbles ΔP = 4γ/r. — one of the key formulas in its field, derived from fundamental physics principles.
The relationship connects physical quantities in a measurable, predictable way. Understanding when and how it applies is as important as the calculation itself.
Real-world applications span many fields: engineering design, scientific research, industrial processes, and everyday phenomena all rely on this formula.
Always verify that inputs are in consistent SI units. The calculator converts common units automatically where indicated, but mixed units are a frequent source of errors.
Formula Reference Table
| Solve For | Formula | Notes |
|---|---|---|
| Surface tension force | F = γ · L | L = contact length (m) |
| Soap bubble ΔP | ΔP = 4γ/r | 2 surfaces; r = radius |
| Droplet ΔP | ΔP = 2γ/r | 1 surface |
| Capillary rise | h = 2γ cos(θ)/(ρgr) | r = tube radius |
| Water at 20°C | γ = 0.0728 N/m | Decreases with temperature |
| Surface energy | E = γ × A | Energy = γ × created area |
3 Worked Examples
Wire frame 10 cm long lifted from water (γ=0.0728). Force?
- F = 2×γ×L (film has 2 surfaces) = 2×0.0728×0.1 = 0.01456 N = 14.6 mN
Soap bubble r = 5 mm, γ = 0.025 N/m.
- ΔP = 4γ/r = 4×0.025/0.005 = 20 Pa
- A tiny pressure — about 0.02% of atmospheric
Water in 0.1 mm radius glass tube (θ ≈ 0°).
- h = 2×0.0728×cos(0°)/(1000×9.81×0.0001) = 0.1456/0.981 = 0.148 m = 14.8 cm
Real-World Applications
Common Mistakes to Avoid
Use SI units.
Apply correct version of formula.
Formula assumes ideal conditions.
Check positive/negative.
Check formula exponents carefully.
Frequently Asked Questions
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Formula Explorer connections
Interpretation: This relationship connects pressure, velocity, density, viscosity, geometry or transport in a fluid system. Assumption: Check whether flow is steady, incompressible, laminar, fully developed or one-dimensional. Reynolds and Mach regimes determine whether simplified formulas are valid.