Surface Tension Unit Converter & Tools
Physics Note: Surface tension is the force per unit length acting along the boundary of a liquid-gas or liquid-liquid interface. It arises from intermolecular forces and creates a tendency to minimize surface area. γ = F/L (Force per unit length).
Result:
Measurement Note: Surface tension is temperature-dependent and typically decreases with increasing temperature. Standard measurements are often reported at 20°C or 25°C.
All Surface Tension Units in One Place
Instantly convert between surface tension units: newton per meter (N/m), dyne per centimeter (dyn/cm), and more. Find tables, formulas, and quick reference for surface tension measurements. Perfect for chemistry, physics, and materials science applications.
Surface Tension Units Table
| Unit Name | Symbol | Conversion to N/m | Common Use |
|---|---|---|---|
| Newton per meter | N/m | 1 | SI unit, modern standard |
| Dyne per centimeter | dyn/cm | 0.001 | CGS unit, traditional |
| Millinewton per meter | mN/m | 0.001 | Small surface tensions |
| Joule per square meter | J/m² | 1 | Energy per unit area |
| Kilogram per second squared | kg/s² | 1 | Fundamental SI units |
| Pound-force per inch | lbf/in | 175.127 | Imperial system |
| Pound-force per foot | lbf/ft | 14.594 | Engineering (US) |
| Erg per square centimeter | erg/cm² | 0.001 | CGS energy units |
Surface Tension Conversion Formulas
Basic Conversions:
• N/m to dyn/cm: N/m × 1,000 = dyn/cm
• dyn/cm to N/m: dyn/cm ÷ 1,000 = N/m
• mN/m to N/m: mN/m ÷ 1,000 = N/m
• J/m² to N/m: J/m² × 1 = N/m (equivalent units)
Unit Equivalencies:
• 1 N/m = 1 J/m² = 1 kg/s² = 1,000 dyn/cm = 1,000 mN/m
• 1 dyn/cm = 1 mN/m = 1 erg/cm²
• N/m to dyn/cm: N/m × 1,000 = dyn/cm
• dyn/cm to N/m: dyn/cm ÷ 1,000 = N/m
• mN/m to N/m: mN/m ÷ 1,000 = N/m
• J/m² to N/m: J/m² × 1 = N/m (equivalent units)
Unit Equivalencies:
• 1 N/m = 1 J/m² = 1 kg/s² = 1,000 dyn/cm = 1,000 mN/m
• 1 dyn/cm = 1 mN/m = 1 erg/cm²
Surface Tension Physics: Surface tension arises from the cohesive forces between liquid molecules at the interface. Molecules at the surface have fewer neighbors, creating an energy imbalance that manifests as surface tension.
Common Surface Tension Values
| Substance | Temperature | Surface Tension (N/m) | Surface Tension (dyn/cm) |
|---|---|---|---|
| Water (pure) | 20°C | 0.0728 | 72.8 |
| Water (pure) | 0°C | 0.0757 | 75.7 |
| Water (pure) | 100°C | 0.0589 | 58.9 |
| Mercury | 20°C | 0.4865 | 486.5 |
| Ethanol | 20°C | 0.0223 | 22.3 |
| Glycerol | 20°C | 0.0634 | 63.4 |
| Benzene | 20°C | 0.0289 | 28.9 |
| Acetone | 20°C | 0.0237 | 23.7 |
| Liquid nitrogen | -196°C | 0.0088 | 8.8 |
| Liquid helium | -269°C | 0.000037 | 0.037 |
Surface Tension Measurement Methods
| Method | Principle | Accuracy | Applications |
|---|---|---|---|
| Wilhelmy Plate | Force on immersed plate | ±0.1% | Standard reference method |
| Du Noüy Ring | Force to lift ring from surface | ±0.5% | Common laboratory method |
| Pendant Drop | Shape analysis of hanging drop | ±0.1% | High-temperature applications |
| Capillary Rise | Height of liquid in capillary | ±1% | Simple, educational |
| Maximum Bubble Pressure | Pressure to form bubble | ±0.5% | Dynamic measurements |
| Spinning Drop | Shape of drop in centrifugal field | ±0.1% | Very low surface tensions |
Factors Affecting Surface Tension
| Factor | Effect | Typical Change | Applications |
|---|---|---|---|
| Temperature | Decreases with heating | -0.1 to -0.2 mN/m per °C | Process design |
| Surfactants | Significantly reduces | Can reduce by 50-90% | Detergents, emulsions |
| Dissolved salts | Usually increases slightly | +1 to +5 mN/m | Seawater, brines |
| Organic solvents | Generally reduces | Variable | Solvent selection |
| pH | Can affect ionic surfactants | Variable | Chemical processing |
| Pressure | Minor effect at moderate pressures | <1% change | High-pressure systems |
Applications in Science and Industry
- Chemistry: Interfacial studies, wetting behavior, adhesion analysis
- Materials Science: Coating applications, composite interfaces, thin films
- Biology: Cell membrane studies, lung surfactant research, protein interfaces
- Petroleum Engineering: Enhanced oil recovery, reservoir studies, emulsion stability
- Food Industry: Emulsion stability, foam characterization, quality control
- Pharmaceuticals: Drug delivery systems, tablet coating, formulation development
- Environmental Science: Water treatment, oil spill cleanup, contamination studies
- Manufacturing: Printing inks, paints, adhesives, surface treatments
Related Physical Properties
Contact Angle: θ = arccos((γSV - γSL)/γLV) - Young's equation
Capillary Length: lc = √(γ/ρg) - characteristic length scale
Weber Number: We = ρv²L/γ - ratio of inertial to surface tension forces
Bond Number: Bo = ρgL²/γ - ratio of gravitational to surface tension forces
Laplace Pressure: ΔP = γ(1/R1 + 1/R2) - pressure difference across curved interface
Capillary Length: lc = √(γ/ρg) - characteristic length scale
Weber Number: We = ρv²L/γ - ratio of inertial to surface tension forces
Bond Number: Bo = ρgL²/γ - ratio of gravitational to surface tension forces
Laplace Pressure: ΔP = γ(1/R1 + 1/R2) - pressure difference across curved interface
Temperature Dependence Examples
| Substance | Temperature Coefficient | Critical Temperature | Notes |
|---|---|---|---|
| Water | -0.152 mN/m·°C | 374°C | Linear near room temperature |
| Ethanol | -0.084 mN/m·°C | 241°C | Moderate temperature dependence |
| Mercury | -0.205 mN/m·°C | 1477°C | Strong temperature dependence |
| Benzene | -0.129 mN/m·°C | 289°C | Typical organic liquid |