I would like to request some clarification regarding areas in surface tension calculations.
In a capillary tube (liquid is water) the meniscus has a curved area (either concave or convex to water, doesn't matter). So when we calculate $F=\Delta PA$, which area is this? In my notes, this has been considered the projected area of the air-liquid interface.
When we calculate $dW=\gamma dA$, where gamma is the surface tension, then which area is this? I think this is the area of the glass-water interface.