  We investigate the outcome of collisions in very different mass regimes, but
an otherwise identical parameter setup, comprising the impact velocity
($v/v_\mathrm{esc}$), impact angle, mass ratio, and initial composition, w.r.t.
simple hydrodynamic scaling. The colliding bodies' masses range from $\simeq
10^{16}$ to $10^{24}$ kg, which includes km-sized planetesimals up to
planetary-sized objects. Our analysis of the results comprises the time
evolution of fragment masses, the fragments' water contents and fragment
dynamics, where we start with bodies consisting of basalt and water ice. The
usual assumption of hydrodynamic scaling over a wider range of masses is based
on material behavior similar to a fluid, or a rubble pile, respectively. All
our simulations are carried out once including full solid-body physics, and
once for strengthless - but otherwise identical - bodies, to test for the
influence of material strength.
  We find that scale-invariance over a wider range of masses is mostly only a
very crude approximation at best, but can be applied to constrained mass ranges
if tested carefully. For the chosen scenarios the outcomes of solid-body
objects compared to strengthless fluid bodies differ most for our intermediate
masses, but are similar for the lowest and highest masses. The most energetic,
planet-sized collisions produce considerably faster and more fragments, which
is also reflected in high water losses - above 50 percent in a single
collision.
