A liquid drop placed on a horizontal plane has a near spherical shape (slightly flattened due to gravity). Let R be
the radius of its largest horizontal section. A small disturbance causes the drop to vibrate with frequency v about
its equilibrium shape. By dimensional analysis the ratio
3
v
σ / ρR
can be (Here σ is surface tension, ρ is density,
g is acceleration due to gravity, and k is arbitrary dimensionless constant)