In many cases, small-scale modeling requires the scaling up of the gra
vitational acceleration. Yet this requirement sets a technical problem
, and unless the use of a centrifuge is available, it is not fulfilled
. Consequently there is a distortion in the extrapolated results of th
e small-scale model, which lacks scaling of gravity. So far, the exten
t of the effect of gravity scaling on the extrapolated results has bee
n speculated. A quantitative way to evaluate this effect is suggested
here. An expression for the distortion in the extrapolation of a measu
red model variable is developed, based on similitude requirements. Thi
s expression depends on the geometrical scaling factor, and on the rat
io of a variable measured model value to the value of its gravitationa
l component. It shows that for geometrical scling factors of 10 and 50
, the distortion is less than 10% when the gravitational component of
the variable is less than 1% and approximately 0.2%, respectively.