  Jet droplets from bubble bursting are determined by a limited parametrical
space: the liquid properties (surface tension, viscosity, and density), mother
bubble size and acceleration of gravity. Thus, the two resulting parameters
from dimensional analysis (usually, the Ohnesorge and Bond numbers, Oh and Bo)
completely define this phenomenon when both the trapped gas in the bubble and
the environment gas have negligible density. A detailed physical description of
the ejection process to model both the ejected droplet radius and its initial
launch speed is provided, leading to a scaling law including both Oh and Bo.
Two critical values of Oh determine two limiting situations: one (Oh$_1$=0.038)
is the critical value for which the ejected droplet size is minimum and the
ejection speed maximum, and the other (Oh$_2$=0.0045) is a new critical value
which signals when viscous effects vanish. Gravity effects (Bo) are
consistently introduced from energy conservation principles. The proposed
scaling laws produce a remarkable collapse of published experimental
measurements collected for both the ejected droplet radius and ejection speed.
