The scaling of Young's modulus of open-cell foam with the sesqui-power of the volume fraction of solid material phase (relative density), observed in experiments on expanded polystyrene foam, with volume fractions of the solid material phase ranging from 0.025 to 0.38, is rationed by employing the elastic solution for the compression of a thin spherical shell as a unit-cell think model for closed-cell foams. The resulting sesqui-power scaling is shown to adequately represent the behavior of other closed-cell foams (e.g. aluminum foams).