Pressure jump across a curved surface: bubble, droplet, or capillary.
| ΔP (Pa) | – |
Use this calculator for a soap bubble, a mercury droplet, or a capillary meniscus when you have surface tension and radius.
The calculation is ΔP = 2γ/r for a sphere (the usual droplet or bubble form used here) and ΔP = γ/r for a cylinder. γ is in N/m, r is converted to metres, ΔP is in Pa. Water is about 0.072 N/m. Radius may be entered in metres (m) or feet (ft).
This is the Young–Laplace jump for a single radius of curvature. A soap bubble with two surfaces is sometimes written 4γ/r; pick sphere only if that 2γ/r convention is what you want.
γ (N/m): Surface tension in N/m. Water ~0.072; mercury ~0.48.
Radius: Radius of curvature in m or ft. 1 mm is 0.001 m.
Interface: Sphere (droplet or bubble as implemented) or cylinder (capillary-style).
ΔP (Pa): Pressure difference in pascals.
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