  We examine how well the physical properties of clumps in turbulent molecular
clouds can be determined by measurements of observed clump structures. We
compare simulated observations of three-dimensional numerical models of
isothermal, magnetized, supersonic turbulence to the actual physical structure
of the models. We determine how changing the parameters of turbulence changes
the structure of the simulations. Stronger driving produces greater density
fluctuations, and longer wavelength driving produces larger structures.
Magnetic fields have a less pronounced effect on structure, and one that is not
monotonic with field strength. Aligned structures are seen only with
low-density tracers, and when the intensity of the field is large. Comparing
different regions with the same tracers (or the same region with different
tracers) can give information about physical conditions: different density
tracers can help determine the size of the density fluctuations and thus the
strength of the driving. Nevertheless, velocity superposition of multiple
physical clumps can fully obscure the physical properties of those clumps, and
short wavelength driving worsens this effect. Regarding Larson's relationships,
we confirm previous claims that the mean density-size relationship is an
artifact of the observations; and the velocity dispersion-size relationship, is
consistent with observations. Regarding the mass spectra, we show that, when we
look for clumps with high enough resolution, they converge to a log-normal
function, rather than the power-law obtained in the literature.
